Yves,
thank you very much for all the suggestions and information with which I will continue my investigation
In the meantime I received the 2.5mm socket wrench and after?a little mod to adapt it?for the purpose (photo), I proceeded to align the spheres of the SYTF
I must say that the operation done under the microscope is quite simple
The nuts must be loosened (not too much) and with a small screwdriver that acts as a delicate lever, ?the supports of?the?spheres can be moved so that the coupling ring completely shadows them (i.e. the sphere is exactly in the center)
Removing the gold mesh was not necessary
The insertion loss has improved enormously:
at 5 GHz it is -6dBm at 6GHz it is -10dB (before the signal starting from this frequency was no longer visible) at 6.5 GHz it is only -3dB
I will install it when I have solved the problem of "blindness" in band 0 since the calibration constants that the instrument has in memory (in practice the tuning current data) are relative to the original SYTF and the "new" SYTW requires a? SYTF CAL is done
Adri
?
?
?
?
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Show quoted text
----- Messaggio originale -----
Inviato: 31/08/2024 03:07:53
Oggetto: Re: [HP-Agilent-Keysight-equipment] HP 5086-7906 YTO
I forgot to send the mixer information.
?
Blue wire, PIN SW: band0= +9.81v and band 1=-9.56V
Green wire, BIAS: +3.9V
?
Yves
?
?
having received no feedback, I continue with a brief update on my attempts to bring my HP8595E back to its former glory 3
Summary and state of the art:
it all started with the failure of the main oscillator YTO (A3A7 on the block diagram); This component was replaced with the same model, purchased "as is" and installed after it was found to work and with good output across the entire range
Once installed, the analyzer returned to sweep (sometimes it gave the error LO UNLVL) but above all it revealed the problem that
no signal present in band 0 (9kHz -2.7GHz) is seen by the analyzer, (so not even the calibration signal which however turned out to be in specification and going to look for it in the analyzer I find it up to the low pass output - A3A3 on the block diagram)
I have not gone further yet
On the contrary, the signals in band 1 (2.7 - 6.5GHz) are visible and correct in frequency but attenuated
That of the attenuation of the signals in the 5- 6.5 GHz region is a fairly well-known problem with this analyzer and the diagnoses on the web have associated it with a misalignment of the yttrium spheres due to the countless thermal cycles that the SYTF undergoes over time
I opened my SYTF (particularly deaf starting from 6GHz) and I was able to see the misalignment in particular of a sphere (in the photo barely visible, under the gold mesh)
I await the arrival of a 2.5mm socket wrench after which I will try to realign
Any suggestions on how to deal with the problem of "blindness" in band 0 are welcome
adri
|
Re: HP 141T Power Supply Help Needed
Bill, ? So you replaced the pass transistor and Q9 then it popped the 3A fuse F4.? And at that point the regulator worked but there must be a short on the -12.6V buss.? Please run an Ohm meter check on the -12.6V buss which is / are the white / violet wires from the A2 assembly.? Check R42, CR16 and Q10.? ?From my calculations the current limiter Q10 should start taking drive away from the driver Q9 at about 2.8A.? ?I take it that no plugins are installed.? The only place in the 141T that the -12.6 goes is / the? plugin connectors, the flood gun filament, and the trace align control on the front panel.? If there is a short (<4 Ohms) then you have to find which wire has that low impedance.? Let me know what you find. ? Mike ?
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From: [email protected] < [email protected]> On Behalf Of Bill Berzinskas Sent: Saturday, August 31, 2024 8:07 AM To: [email protected]Subject: Re: [HP-Agilent-Keysight-equipment] HP 141T Power Supply Help Needed ? Those numbers just don't make any sense.??? I pulled all the transistors AGAIN, desoldered and cleaned.? Tested them all with a meter, repopulate.??? Back to 23.5v....??? ? On Fri, Aug 30, 2024, 6:22?PM Bill Berzinskas via <bberzinskas=[email protected]> wrote: Replaced Q9, powered on and blew the fuse.? ?Replaced Fuse?+ Q9 again?+ pass transistor and no fuse pop.? ?
Not sure if better, worse or just different :-)?
B = 54v?!? (was 23.5v)
E = -17v.?
Q10..
C = 54v..? (was 23.5v)
b = 0.58v (up from 0)? E = 0v
Q11..?
C= 54.7 (was 23.5v)
B = -.64
E = 0 ? On Fri, Aug 30, 2024 at 5:48?PM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? OK it seems that Q 9 has a base-emitter voltage of 38.5V which says that the base-emitter junction is open because a good NPN silicon transistor can only have a forward base-emitter voltage of 1V under extreme conditions.? Normally the Vbe is in the order of 0.7V. If the emitter or base connection of Q9 were open the emitter voltage will be dragged negative by R41.? That is not good for the pass transistor Q4 to see that much negative voltage because that will exceed the Vebo rating of the pass device which may degrade the Beta of the pass device.? Basically it will Zener the base emitter junction with that much reverse bias.? Typical Vebo is in the order of <10V which is in the absolute maximum ratings of the part.? A 2N3053 should work OK as the driver Q9.? Let me know how it goes. ? Mike ? ? That does make sense,?thank you for that explanation..? I do believe I've stated it backwards.? ? 22v appears on a 2n3053 that I've replaced at pin 3, which is actually the collector..? :facepalm:..? Remeasure / restate Q9..? ? On Fri, Aug 30, 2024 at 3:02?PM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? Lets back up a minute¡ If there is +22V at the emitter of the driver Q9 then there must be +22V at the base of the series regulator Q4 and you say that there is less than 1V ?at the emitter of the pass transistor Q4 and also no voltage at the top of R42 (the current sense resistor) then there is 22V across the base emitter junction of? Q4 and that can only be a failed device or some bad wiring or even a cracked runner on the board. A good NPN transistor has no more than 1V Vbe.? ??Does that make sense to you?? Or is the voltage at the emitter of the driver Q9 a negative 22V?? If the voltage at the emitter of Q9 is negative then what is the voltage at the base of Q9? ? Mike ? ? Ok..? I had a few bad transistors in the mix, but the one that was in the unit checks out ok.? ? ?I tossed a small handful to alleviate future issues.? ?
I spent a little time simulating this and from what I'm seeing this almost has to be a problem w/ the voltage divider / potentiometer.? ?I can do a lot of "shady" things in the sim and none of them give me issues like I'm seeing.? ?Removing R43 in the sim, or the pullup R45 seem to skew the voltages like I'm seeing.? ? ?The sim shows that the trimpot is kind of what "kicks things off", and the fact that I'm only getting about -1v here seems to further hint towards R43.? ? I don't have a 22.1k or even a 22k on hand, so I'll probably get creative to see what happens.? ?Resistance measurements on the pot itself look ok, i'm really hoping to not have to yank that thing.?? ? On Fri, Aug 30, 2024 at 11:58?AM Bill Berzinskas via <bberzinskas=[email protected]> wrote: I'll check these over lunch.? ?Interestingly, two of the original transistors in that spot cause the 3a fuse to blow.? ?Now sure if thats indicative of something else going on w/ a good transistor in the seat..? ? tbd.?? ? On Fri, Aug 30, 2024 at 11:43?AM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? 22V on the emitter of the driver is very strange.? It seems that the pass transistor Q2 has an open base ¨C emitter junction and a shorted collector base junction to come up with those voltages.? That would explain the ¡°on output¡± situation.?? An Ohm meter should be sufficient to check the status of Q2.? If your meter has a diode scale, that would give you a quick indication of the status of Q2.? ? I am thinking ?of designing an over voltage crowbar circuit to protect the -12.6 V supply from damaging sensitive circuits down stream of this supply if the regulator goes to an over voltage condition.? Some of the plugins appear to have a crowbar in just such a condition.? The filament of the flood gun is run from the -12.6V and in my case it went over voltage and it burned out the flood gun filament. ? ? Mike ? ? Thanks Michael,?
here's a recap what i'm seeing around the -12.6v line currently:?
?.65v at base of q11 sensor amp, .275v on collector.?? Driver has 22v on emitter, .27v on base and -.27v collector.????? Not much happening on the current limiter.?? 0v base.? ? On Fri, Aug 30, 2024 at 11:15?AM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? OK so you have the early version of the supply.? If you give me the voltages at the base of the driver transistors I can perhaps give you some more pointers. ? Mike ? ? correction, it did have the LAMP..? ?? ? My unit is 1615a prefix, it did have the zener and it was measuring closer to 100v instead of the expected 83 or whatever.? It has since been replaced by a pair of diodes that bring it to 89v but I have had to replace that string at least once in my travels so far, so I will eventually look for a more permanent?solution as I've read about.? ?I can check that again this evening!? ?I stopped thinking about it after I got the?+100v supply up! ? On Thu, Aug 29, 2024 at 4:50?PM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? There are 2 versions of this supply.? There is an early version that has a neon tube as the reference for the +100V supply and a later version that uses a 9V temp compensated Zener that is floating.? That is the reference Zener is connected from the +100V rail and the base of Q4.? It may help to know which version you have.? From my schematic the +100 V is the master and the other supplies are referenced from it.?? The one I have has a serial number prefix 2101A and it appears to be made in the late 1981 or early 1982 time frame. This one has the floating 9V Zener. ? Mike ? ? Finished that up.? ?On the -100 I can adjust up to 96v, a little low but it is adjustable so I think I should come back to that later.??
On 248v I'm currently seeing 290v, and -12v I'm seeing -1.5v.? ? ?I reckon I could go after either of them given the dependencies.? ? Will grab some measurements in between or after work today.? ? ? On Thu, Aug 29, 2024 at 10:52?AM Bill Berzinskas via <bberzinskas=[email protected]> wrote: Well, this is awkward.? ? I had replaced both Diff Amp transistors with the same part number.??
I just found that this package is actually reverse from what i removed!? ?using a dorky little? heathkit transistor tester, i found the pinout to be CBE when looking at it from the flat side.??
The center leg was bent towards the rear of the part, while the original part was bent toward the front.??
I reversed both transistors, and got -106 which i was able to adjust appropriately!? ? ??
Strange, but makes sense.? ?I have a few more of these buggers in the supply, so it sounds like I'll be sorting through that today.? ? Will report back in a bit.??
Thanks for the help ya'll!? ? On Thu, Aug 29, 2024 at 10:45?AM Frank Mashockie via <fmashockie=[email protected]> wrote: Also, don't forget about Gianni's HP e-book.? If I remember correctly, he goes into great detail about the 141T.? Here's the link.? They can be slow to download and I forget which section includes the 141T. ?
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Re: 16901A 16901-14102 recovery disc ISO wanted (was Re: [HP-Agilent-Keysight-equipment] Wanted: 16902B recovery DVD, p/n 16902-14100)
Maybe only on certain interfaces?
?
There's definitely nothing wrong w their configuration when you're close (network and latency-wise) to them. I mean, they often saturate the SSD disk writing limits(usually artificially limited by the providers) on the boxes I setup. Nothing handicapped there!
?
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Re: 16901A 16901-14102 recovery disc ISO wanted (was Re: [HP-Agilent-Keysight-equipment] Wanted: 16902B recovery DVD, p/n 16902-14100)
I wonder whether internet archive simply has TCP 1323 window scaling options disabled or clamped to a low maximum, or something like path mtu discovery broken by blocking ICMP type 3 code 4 packet too big messages (or both). In general firewall
policies deny everything not explicitly allowed, so allowing ping and perhaps trace route and then denying other ICMP messages can lead to poor or even broken behavior. All modern operating systems, at least those not on IOT devices expect to discover path
maximum transfer units by sending ?packets with the don¡¯t fragment but set, and using the ICMP messages they expect to receive to adjust their sending size. This leads to interesting problems like TCP handshakes that succeed then, due following a certificate
exchange setting up SSL/TLS encryption or poor throughput when (if) fallback occurs.
This is conjecture, as I haven¡¯t taken packet captures to confirm.
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Re: 16901A 16901-14102 recovery disc ISO wanted (was Re: [HP-Agilent-Keysight-equipment] Wanted: 16902B recovery DVD, p/n 16902-14100)
Here's the images I have
?
?
File sizes and MD5sums
?
-rwxr-xr-x 1 root root 1874239488 Mar 21 ?2019 16900-14121.ISO
a3832026cd7817a2e2b958f8eb3ed78b ?16900-14121.iso
?
63197d5ffe6697ae5b7cc05a283c6d0e ?16900-14122 BIOS Upgrade.iso
-rwxr-xr-x 1 root root 67776512 Mar 21 ?2019 '16900-14122 BIOS Upgrade.iso'
?
For the IA download stuff, you should use something like aria2c:
?
This allows multiple streams.... I usually use is -x 16 and -s 16 arguments. Works great.
?
While I haven't figured out the exact limitation, I'm pretty sure the peering arrangements for the various transiting providers limit each individual connection to just under 4MB/s. If you're seeing that magic number, then that's what's happening. I've seen this for years across a variety of places.... so you need to use multiple connections.
?
The other thing, is IA has a TON of bandwidth. If you can get closer to them, without transiting, you'll get ridiculous speeds. I'm talking like 20gbps. It's a bit of a pain in the butt just to download something, but it works. I use FTP to backhaul stuff from machines closer to San Francisco, with multiple streams.... usually (10) at a time with programs like WinFTP.
?
With all these suggestions, you need to point this to the actual endpoint where the file is stored..... the path will be revealed when you try to download normally.... If you just point to the link you hover over in your browser, it's not going to work, because aria2c etc won't always follow depending on how they do it.
?
Hope this helps.
?
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Re: HP 141T Power Supply Help Needed
Those numbers just don't make any sense.??? I pulled all the transistors AGAIN, desoldered and cleaned.? Tested them all with a meter, repopulate.??? Back to 23.5v....???
On Fri, Aug 30, 2024, 6:22?PM Bill Berzinskas via <bberzinskas= [email protected]> wrote: Replaced Q9, powered on and blew the fuse.? ?Replaced Fuse?+ Q9 again?+ pass transistor and no fuse pop.? ? Not sure if better, worse or just different :-)? Q9..? C = 22v B = 54v?!? (was 23.5v)
E = -17v.?
Q10..
C = 54v..? (was 23.5v)
b = 0.58v (up from 0)? E = 0v
Q11..?
C= 54.7 (was 23.5v)
B = -.64
E = 0
On Fri, Aug 30, 2024 at 5:48?PM Michael Bafaro via <m.bafaro= [email protected]> wrote: Bill, ? OK it seems that Q 9 has a base-emitter voltage of 38.5V which says that the base-emitter junction is open because a good NPN silicon transistor can only have a forward base-emitter voltage of 1V under extreme conditions.? Normally the Vbe is in the order of 0.7V. If the emitter or base connection of Q9 were open the emitter voltage will be dragged negative by R41.? That is not good for the pass transistor Q4 to see that much negative voltage because that will exceed the Vebo rating of the pass device which may degrade the Beta of the pass device.? Basically it will Zener the base emitter junction with that much reverse bias.? Typical Vebo is in the order of <10V which is in the absolute maximum ratings of the part.? A 2N3053 should work OK as the driver Q9.? Let me know how it goes. ? Mike ? ? That does make sense,?thank you for that explanation..? I do believe I've stated it backwards.? ? 22v appears on a 2n3053 that I've replaced at pin 3, which is actually the collector..? :facepalm:..? Remeasure / restate Q9..? ? On Fri, Aug 30, 2024 at 3:02?PM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? Lets back up a minute¡ If there is +22V at the emitter of the driver Q9 then there must be +22V at the base of the series regulator Q4 and you say that there is less than 1V ?at the emitter of the pass transistor Q4 and also no voltage at the top of R42 (the current sense resistor) then there is 22V across the base emitter junction of? Q4 and that can only be a failed device or some bad wiring or even a cracked runner on the board. A good NPN transistor has no more than 1V Vbe.? ??Does that make sense to you?? Or is the voltage at the emitter of the driver Q9 a negative 22V?? If the voltage at the emitter of Q9 is negative then what is the voltage at the base of Q9? ? Mike ? ? Ok..? I had a few bad transistors in the mix, but the one that was in the unit checks out ok.? ? ?I tossed a small handful to alleviate future issues.? ?
I spent a little time simulating this and from what I'm seeing this almost has to be a problem w/ the voltage divider / potentiometer.? ?I can do a lot of "shady" things in the sim and none of them give me issues like I'm seeing.? ?Removing R43 in the sim, or the pullup R45 seem to skew the voltages like I'm seeing.? ? ?The sim shows that the trimpot is kind of what "kicks things off", and the fact that I'm only getting about -1v here seems to further hint towards R43.? ? I don't have a 22.1k or even a 22k on hand, so I'll probably get creative to see what happens.? ?Resistance measurements on the pot itself look ok, i'm really hoping to not have to yank that thing.?? ? On Fri, Aug 30, 2024 at 11:58?AM Bill Berzinskas via <bberzinskas=[email protected]> wrote: I'll check these over lunch.? ?Interestingly, two of the original transistors in that spot cause the 3a fuse to blow.? ?Now sure if thats indicative of something else going on w/ a good transistor in the seat..? ? tbd.?? ? On Fri, Aug 30, 2024 at 11:43?AM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? 22V on the emitter of the driver is very strange.? It seems that the pass transistor Q2 has an open base ¨C emitter junction and a shorted collector base junction to come up with those voltages.? That would explain the ¡°on output¡± situation.?? An Ohm meter should be sufficient to check the status of Q2.? If your meter has a diode scale, that would give you a quick indication of the status of Q2.? ? I am thinking ?of designing an over voltage crowbar circuit to protect the -12.6 V supply from damaging sensitive circuits down stream of this supply if the regulator goes to an over voltage condition.? Some of the plugins appear to have a crowbar in just such a condition.? The filament of the flood gun is run from the -12.6V and in my case it went over voltage and it burned out the flood gun filament. ? ? Mike ? ? Thanks Michael,?
here's a recap what i'm seeing around the -12.6v line currently:?
?.65v at base of q11 sensor amp, .275v on collector.?? Driver has 22v on emitter, .27v on base and -.27v collector.????? Not much happening on the current limiter.?? 0v base.? ? On Fri, Aug 30, 2024 at 11:15?AM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? OK so you have the early version of the supply.? If you give me the voltages at the base of the driver transistors I can perhaps give you some more pointers. ? Mike ? ? correction, it did have the LAMP..? ?? ? My unit is 1615a prefix, it did have the zener and it was measuring closer to 100v instead of the expected 83 or whatever.? It has since been replaced by a pair of diodes that bring it to 89v but I have had to replace that string at least once in my travels so far, so I will eventually look for a more permanent?solution as I've read about.? ?I can check that again this evening!? ?I stopped thinking about it after I got the?+100v supply up! ? On Thu, Aug 29, 2024 at 4:50?PM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? There are 2 versions of this supply.? There is an early version that has a neon tube as the reference for the +100V supply and a later version that uses a 9V temp compensated Zener that is floating.? That is the reference Zener is connected from the +100V rail and the base of Q4.? It may help to know which version you have.? From my schematic the +100 V is the master and the other supplies are referenced from it.?? The one I have has a serial number prefix 2101A and it appears to be made in the late 1981 or early 1982 time frame. This one has the floating 9V Zener. ? Mike ? ? Finished that up.? ?On the -100 I can adjust up to 96v, a little low but it is adjustable so I think I should come back to that later.??
On 248v I'm currently seeing 290v, and -12v I'm seeing -1.5v.? ? ?I reckon I could go after either of them given the dependencies.? ? Will grab some measurements in between or after work today.? ? ? On Thu, Aug 29, 2024 at 10:52?AM Bill Berzinskas via <bberzinskas=[email protected]> wrote: Well, this is awkward.? ? I had replaced both Diff Amp transistors with the same part number.??
I just found that this package is actually reverse from what i removed!? ?using a dorky little? heathkit transistor tester, i found the pinout to be CBE when looking at it from the flat side.??
The center leg was bent towards the rear of the part, while the original part was bent toward the front.??
I reversed both transistors, and got -106 which i was able to adjust appropriately!? ? ??
Strange, but makes sense.? ?I have a few more of these buggers in the supply, so it sounds like I'll be sorting through that today.? ? Will report back in a bit.??
Thanks for the help ya'll!? ? On Thu, Aug 29, 2024 at 10:45?AM Frank Mashockie via <fmashockie=[email protected]> wrote: Also, don't forget about Gianni's HP e-book.? If I remember correctly, he goes into great detail about the 141T.? Here's the link.? They can be slow to download and I forget which section includes the 141T. ?
|
I forgot to send the mixer information. ? Blue wire, PIN SW: band0= +9.81v and band 1=-9.56V Green wire, BIAS: +3.9V ? Yves ? ? having received no feedback, I continue with a brief update on my attempts to bring my HP8595E back to its former glory 3
Summary and state of the art:
it all started with the failure of the main oscillator YTO (A3A7 on the block diagram); This component was replaced with the same model, purchased "as is" and installed after it was found to work and with good output across the entire range
Once installed, the analyzer returned to sweep (sometimes it gave the error LO UNLVL) but above all it revealed the problem that
no signal present in band 0 (9kHz -2.7GHz) is seen by the analyzer, (so not even the calibration signal which however turned out to be in specification and going to look for it in the analyzer I find it up to the low pass output - A3A3 on the block diagram)
I have not gone further yet
On the contrary, the signals in band 1 (2.7 - 6.5GHz) are visible and correct in frequency but attenuated
That of the attenuation of the signals in the 5- 6.5 GHz region is a fairly well-known problem with this analyzer and the diagnoses on the web have associated it with a misalignment of the yttrium spheres due to the countless thermal cycles that the SYTF undergoes over time
I opened my SYTF (particularly deaf starting from 6GHz) and I was able to see the misalignment in particular of a sphere (in the photo barely visible, under the gold mesh)
I await the arrival of a 2.5mm socket wrench after which I will try to realign
Any suggestions on how to deal with the problem of "blindness" in band 0 are welcome
adri
|
Hi Adri, ? sorry for not giving feedback earlier, I've been very busy this week, and the days have been very long. ? For band 0, if you have a signal at A3A3 output, but nothing at A3A6 output at J2, the mixer or internal switch has a problem. Since band 1 seems to work (but needs YTM alignment), you should check that the LO frequency is correct for band 0. ? Still for band 0, with the calibrator connected, you have -20dBm at the input, but at the output of the A3A3 module, you should have -31.5dBm ¡À1.5dB. Based on a test I just did on my 8595E: after a preset, the loss from input to output A3A3 (w27, connector J2) is -10.56dB at low frequencies, -12.5dB at 2.9GHz, and finally, -11.1dB at 300MHz. Which roughly corresponds to the information on the block diagram. ? A test on the FL1 filter at 3.914GHz, gives only -0.14dB of insertion loss. ? Now, the 300 MHz calibrator at -20dBm, connected to the Spectrum input...at the mixer output, the level is -43.3dBm (specification, between -38 and -45 dBm), again, consistent with the information in the block diagram. ? To test the YTF I used an 8350B/83595A. ? Config on the 8595E: Preset center freq =3GHz ZERO span ? Config on the IF measurement Spectrum: Preset center freq =321.4MHz span 200 MHz ? For the 8350B/83595A Preset CF=3GHz Span 200MHz ? Connected to the mixer output, at the end of the w22 cable to A3A4. I did three tests: 3GHz, 5GHz and 6.5GHz. The measurement Spectrum for the 321.4MHz frequency is not manipulated during the test. It is just a matter of changing the frequency on the generator, here it is the 8350B, and on the 8595E for each of the three tests. ? By connecting to the end of the w22 cable, we can see the YTF tuned bandpass curve without any other filtering. ? The image shows: yellow curve -> test at 3GHz cyan curve -> test at 5GHz magenta curve -> test at 6.5GHz ? For a 0dBm signal at the input, I get an average close to -28dBm at the mixer output. Normally expected according to the block diagram, between -24 and -35 dBm. ? Now, if you look at the ZOOM image we find the same curves, but in a span of 5MHz, this in order to see what is the impact in a resBW of 3MHz and 5 MHz for an extended range. ? (ZOOM PRESEL PEAK), The yellow curve is the test at 3GHz with the calibrated values, named PRESEL default, and the cyan curve is after having done a PRESEL PEAK. In this case the YTF is finely adjusted to have a better centering, thus a better flatness for the IF filtering that will follow. ? PRESEL DEFAULT 3MHz -> flatness 0.3dBpp 5MHz -> flatness 0.6dBpp ? After PRESEL PEAK 3MHz -> flatness 0.04dBpp 5MHz -> flatness 0.06dBpp ? ------------------ About the problem of "blindness" in band 0: ? If you look at the image ¡°IF 3.9214GHz and LO leakage from mixer at 4.2214GHz.png¡±, we see the LO leakage through the mixer, are you able to see this signal? For the 300MHz calibrator, the LO is at 4.2214GHz ? Maybe it's a simple BIAS issue, but you may have already checked. ? Hope this information can help you. ? Yves ===================================================== ? De?: [email protected] <HP-Agilent-Keysight- [email protected]> De la part de alfa beta
·¡²Ô±¹´Ç²â¨¦?: 30 ao?t 2024 09:26
??: [email protected]
Objet?: Re: [HP-Agilent-Keysight-equipment] HP 5086-7906 YTO ? having received no feedback, I continue with a brief update on my attempts to bring my HP8595E back to its former glory 3
Summary and state of the art:
it all started with the failure of the main oscillator YTO (A3A7 on the block diagram); This component was replaced with the same model, purchased "as is" and installed after it was found to work and with good output across the entire range
Once installed, the analyzer returned to sweep (sometimes it gave the error LO UNLVL) but above all it revealed the problem that
no signal present in band 0 (9kHz -2.7GHz) is seen by the analyzer, (so not even the calibration signal which however turned out to be in specification and going to look for it in the analyzer I find it up to the low pass output - A3A3 on the block diagram)
I have not gone further yet
On the contrary, the signals in band 1 (2.7 - 6.5GHz) are visible and correct in frequency but attenuated
That of the attenuation of the signals in the 5- 6.5 GHz region is a fairly well-known problem with this analyzer and the diagnoses on the web have associated it with a misalignment of the yttrium spheres due to the countless thermal cycles that the SYTF undergoes over time
I opened my SYTF (particularly deaf starting from 6GHz) and I was able to see the misalignment in particular of a sphere (in the photo barely visible, under the gold mesh)
I await the arrival of a 2.5mm socket wrench after which I will try to realign
Any suggestions on how to deal with the problem of "blindness" in band 0 are welcome
adri
|
Re: HP 141T Power Supply Help Needed
Replaced Q9, powered on and blew the fuse.? ?Replaced Fuse?+ Q9 again?+ pass transistor and no fuse pop.? ? Not sure if better, worse or just different :-)? Q9..? C = 22v B = 54v?!? (was 23.5v)
E = -17v.?
Q10..
C = 54v..? (was 23.5v)
b = 0.58v (up from 0)? E = 0v
Q11..?
C= 54.7 (was 23.5v)
B = -.64
E = 0
On Fri, Aug 30, 2024 at 5:48?PM Michael Bafaro via <m.bafaro= [email protected]> wrote: Bill, ? OK it seems that Q 9 has a base-emitter voltage of 38.5V which says that the base-emitter junction is open because a good NPN silicon transistor can only have a forward base-emitter voltage of 1V under extreme conditions.? Normally the Vbe is in the order of 0.7V. If the emitter or base connection of Q9 were open the emitter voltage will be dragged negative by R41.? That is not good for the pass transistor Q4 to see that much negative voltage because that will exceed the Vebo rating of the pass device which may degrade the Beta of the pass device.? Basically it will Zener the base emitter junction with that much reverse bias.? Typical Vebo is in the order of <10V which is in the absolute maximum ratings of the part.? A 2N3053 should work OK as the driver Q9.? Let me know how it goes. ? Mike ? ? That does make sense,?thank you for that explanation..? I do believe I've stated it backwards.? ? 22v appears on a 2n3053 that I've replaced at pin 3, which is actually the collector..? :facepalm:..? Remeasure / restate Q9..? ? On Fri, Aug 30, 2024 at 3:02?PM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? Lets back up a minute¡ If there is +22V at the emitter of the driver Q9 then there must be +22V at the base of the series regulator Q4 and you say that there is less than 1V ?at the emitter of the pass transistor Q4 and also no voltage at the top of R42 (the current sense resistor) then there is 22V across the base emitter junction of? Q4 and that can only be a failed device or some bad wiring or even a cracked runner on the board. A good NPN transistor has no more than 1V Vbe.? ??Does that make sense to you?? Or is the voltage at the emitter of the driver Q9 a negative 22V?? If the voltage at the emitter of Q9 is negative then what is the voltage at the base of Q9? ? Mike ? ? Ok..? I had a few bad transistors in the mix, but the one that was in the unit checks out ok.? ? ?I tossed a small handful to alleviate future issues.? ?
I spent a little time simulating this and from what I'm seeing this almost has to be a problem w/ the voltage divider / potentiometer.? ?I can do a lot of "shady" things in the sim and none of them give me issues like I'm seeing.? ?Removing R43 in the sim, or the pullup R45 seem to skew the voltages like I'm seeing.? ? ?The sim shows that the trimpot is kind of what "kicks things off", and the fact that I'm only getting about -1v here seems to further hint towards R43.? ? I don't have a 22.1k or even a 22k on hand, so I'll probably get creative to see what happens.? ?Resistance measurements on the pot itself look ok, i'm really hoping to not have to yank that thing.?? ? On Fri, Aug 30, 2024 at 11:58?AM Bill Berzinskas via <bberzinskas=[email protected]> wrote: I'll check these over lunch.? ?Interestingly, two of the original transistors in that spot cause the 3a fuse to blow.? ?Now sure if thats indicative of something else going on w/ a good transistor in the seat..? ? tbd.?? ? On Fri, Aug 30, 2024 at 11:43?AM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? 22V on the emitter of the driver is very strange.? It seems that the pass transistor Q2 has an open base ¨C emitter junction and a shorted collector base junction to come up with those voltages.? That would explain the ¡°on output¡± situation.?? An Ohm meter should be sufficient to check the status of Q2.? If your meter has a diode scale, that would give you a quick indication of the status of Q2.? ? I am thinking ?of designing an over voltage crowbar circuit to protect the -12.6 V supply from damaging sensitive circuits down stream of this supply if the regulator goes to an over voltage condition.? Some of the plugins appear to have a crowbar in just such a condition.? The filament of the flood gun is run from the -12.6V and in my case it went over voltage and it burned out the flood gun filament. ? ? Mike ? ? Thanks Michael,?
here's a recap what i'm seeing around the -12.6v line currently:?
?.65v at base of q11 sensor amp, .275v on collector.?? Driver has 22v on emitter, .27v on base and -.27v collector.????? Not much happening on the current limiter.?? 0v base.? ? On Fri, Aug 30, 2024 at 11:15?AM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? OK so you have the early version of the supply.? If you give me the voltages at the base of the driver transistors I can perhaps give you some more pointers. ? Mike ? ? correction, it did have the LAMP..? ?? ? My unit is 1615a prefix, it did have the zener and it was measuring closer to 100v instead of the expected 83 or whatever.? It has since been replaced by a pair of diodes that bring it to 89v but I have had to replace that string at least once in my travels so far, so I will eventually look for a more permanent?solution as I've read about.? ?I can check that again this evening!? ?I stopped thinking about it after I got the?+100v supply up! ? On Thu, Aug 29, 2024 at 4:50?PM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? There are 2 versions of this supply.? There is an early version that has a neon tube as the reference for the +100V supply and a later version that uses a 9V temp compensated Zener that is floating.? That is the reference Zener is connected from the +100V rail and the base of Q4.? It may help to know which version you have.? From my schematic the +100 V is the master and the other supplies are referenced from it.?? The one I have has a serial number prefix 2101A and it appears to be made in the late 1981 or early 1982 time frame. This one has the floating 9V Zener. ? Mike ? ? Finished that up.? ?On the -100 I can adjust up to 96v, a little low but it is adjustable so I think I should come back to that later.??
On 248v I'm currently seeing 290v, and -12v I'm seeing -1.5v.? ? ?I reckon I could go after either of them given the dependencies.? ? Will grab some measurements in between or after work today.? ? ? On Thu, Aug 29, 2024 at 10:52?AM Bill Berzinskas via <bberzinskas=[email protected]> wrote: Well, this is awkward.? ? I had replaced both Diff Amp transistors with the same part number.??
I just found that this package is actually reverse from what i removed!? ?using a dorky little? heathkit transistor tester, i found the pinout to be CBE when looking at it from the flat side.??
The center leg was bent towards the rear of the part, while the original part was bent toward the front.??
I reversed both transistors, and got -106 which i was able to adjust appropriately!? ? ??
Strange, but makes sense.? ?I have a few more of these buggers in the supply, so it sounds like I'll be sorting through that today.? ? Will report back in a bit.??
Thanks for the help ya'll!? ? On Thu, Aug 29, 2024 at 10:45?AM Frank Mashockie via <fmashockie=[email protected]> wrote: Also, don't forget about Gianni's HP e-book.? If I remember correctly, he goes into great detail about the 141T.? Here's the link.? They can be slow to download and I forget which section includes the 141T. ?
|
Re: HP 141T Power Supply Help Needed
Bill, ? OK it seems that Q 9 has a base-emitter voltage of 38.5V which says that the base-emitter junction is open because a good NPN silicon transistor can only have a forward base-emitter voltage of 1V under extreme conditions.? Normally the Vbe is in the order of 0.7V. If the emitter or base connection of Q9 were open the emitter voltage will be dragged negative by R41.? That is not good for the pass transistor Q4 to see that much negative voltage because that will exceed the Vebo rating of the pass device which may degrade the Beta of the pass device.? Basically it will Zener the base emitter junction with that much reverse bias.? Typical Vebo is in the order of <10V which is in the absolute maximum ratings of the part.? A 2N3053 should work OK as the driver Q9.? Let me know how it goes. ? Mike ?
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Show quoted text
From: [email protected] < [email protected]> On Behalf Of Bill Berzinskas Sent: Friday, August 30, 2024 2:56 PM To: [email protected]Subject: Re: [HP-Agilent-Keysight-equipment] HP 141T Power Supply Help Needed ? That does make sense,?thank you for that explanation..? I do believe I've stated it backwards.? ? 22v appears on a 2n3053 that I've replaced at pin 3, which is actually the collector..? :facepalm:..? Remeasure / restate Q9..? ? On Fri, Aug 30, 2024 at 3:02?PM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? Lets back up a minute¡ If there is +22V at the emitter of the driver Q9 then there must be +22V at the base of the series regulator Q4 and you say that there is less than 1V ?at the emitter of the pass transistor Q4 and also no voltage at the top of R42 (the current sense resistor) then there is 22V across the base emitter junction of? Q4 and that can only be a failed device or some bad wiring or even a cracked runner on the board. A good NPN transistor has no more than 1V Vbe.? ??Does that make sense to you?? Or is the voltage at the emitter of the driver Q9 a negative 22V?? If the voltage at the emitter of Q9 is negative then what is the voltage at the base of Q9? ? Mike ? ? Ok..? I had a few bad transistors in the mix, but the one that was in the unit checks out ok.? ? ?I tossed a small handful to alleviate future issues.? ?
I spent a little time simulating this and from what I'm seeing this almost has to be a problem w/ the voltage divider / potentiometer.? ?I can do a lot of "shady" things in the sim and none of them give me issues like I'm seeing.? ?Removing R43 in the sim, or the pullup R45 seem to skew the voltages like I'm seeing.? ? ?The sim shows that the trimpot is kind of what "kicks things off", and the fact that I'm only getting about -1v here seems to further hint towards R43.? ? I don't have a 22.1k or even a 22k on hand, so I'll probably get creative to see what happens.? ?Resistance measurements on the pot itself look ok, i'm really hoping to not have to yank that thing.?? ? On Fri, Aug 30, 2024 at 11:58?AM Bill Berzinskas via <bberzinskas=[email protected]> wrote: I'll check these over lunch.? ?Interestingly, two of the original transistors in that spot cause the 3a fuse to blow.? ?Now sure if thats indicative of something else going on w/ a good transistor in the seat..? ? tbd.?? ? On Fri, Aug 30, 2024 at 11:43?AM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? 22V on the emitter of the driver is very strange.? It seems that the pass transistor Q2 has an open base ¨C emitter junction and a shorted collector base junction to come up with those voltages.? That would explain the ¡°on output¡± situation.?? An Ohm meter should be sufficient to check the status of Q2.? If your meter has a diode scale, that would give you a quick indication of the status of Q2.? ? I am thinking ?of designing an over voltage crowbar circuit to protect the -12.6 V supply from damaging sensitive circuits down stream of this supply if the regulator goes to an over voltage condition.? Some of the plugins appear to have a crowbar in just such a condition.? The filament of the flood gun is run from the -12.6V and in my case it went over voltage and it burned out the flood gun filament. ? ? Mike ? ? Thanks Michael,?
here's a recap what i'm seeing around the -12.6v line currently:?
?.65v at base of q11 sensor amp, .275v on collector.?? Driver has 22v on emitter, .27v on base and -.27v collector.????? Not much happening on the current limiter.?? 0v base.? ? On Fri, Aug 30, 2024 at 11:15?AM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? OK so you have the early version of the supply.? If you give me the voltages at the base of the driver transistors I can perhaps give you some more pointers. ? Mike ? ? correction, it did have the LAMP..? ?? ? My unit is 1615a prefix, it did have the zener and it was measuring closer to 100v instead of the expected 83 or whatever.? It has since been replaced by a pair of diodes that bring it to 89v but I have had to replace that string at least once in my travels so far, so I will eventually look for a more permanent?solution as I've read about.? ?I can check that again this evening!? ?I stopped thinking about it after I got the?+100v supply up! ? On Thu, Aug 29, 2024 at 4:50?PM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? There are 2 versions of this supply.? There is an early version that has a neon tube as the reference for the +100V supply and a later version that uses a 9V temp compensated Zener that is floating.? That is the reference Zener is connected from the +100V rail and the base of Q4.? It may help to know which version you have.? From my schematic the +100 V is the master and the other supplies are referenced from it.?? The one I have has a serial number prefix 2101A and it appears to be made in the late 1981 or early 1982 time frame. This one has the floating 9V Zener. ? Mike ? ? Finished that up.? ?On the -100 I can adjust up to 96v, a little low but it is adjustable so I think I should come back to that later.??
On 248v I'm currently seeing 290v, and -12v I'm seeing -1.5v.? ? ?I reckon I could go after either of them given the dependencies.? ? Will grab some measurements in between or after work today.? ? ? On Thu, Aug 29, 2024 at 10:52?AM Bill Berzinskas via <bberzinskas=[email protected]> wrote: Well, this is awkward.? ? I had replaced both Diff Amp transistors with the same part number.??
I just found that this package is actually reverse from what i removed!? ?using a dorky little? heathkit transistor tester, i found the pinout to be CBE when looking at it from the flat side.??
The center leg was bent towards the rear of the part, while the original part was bent toward the front.??
I reversed both transistors, and got -106 which i was able to adjust appropriately!? ? ??
Strange, but makes sense.? ?I have a few more of these buggers in the supply, so it sounds like I'll be sorting through that today.? ? Will report back in a bit.??
Thanks for the help ya'll!? ? On Thu, Aug 29, 2024 at 10:45?AM Frank Mashockie via <fmashockie=[email protected]> wrote: Also, don't forget about Gianni's HP e-book.? If I remember correctly, he goes into great detail about the 141T.? Here's the link.? They can be slow to download and I forget which section includes the 141T. ?
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Re: 85097A VNA ECal controller replacement
Interesting project, have you made further progress with this? Did you manage to use the Arduino or are you still using the FTDI chip instead?
?
Thanks
Saevar
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Re: Wanted HP-3586 A,B, or C
Hi Matt,
?
Sorry for the late reply. I had not checked after I did get a chance to buy one. Price was too high for me. Fair Radio Sales had two for sale each for $450 with no takers for over a couple of years. They went out of business last month and auctioned them off. I don't know how much they got for them, but I did not want to buy a 3586 and ship it. I could drive out and back to Ohio for it either. I? had two working at one time, but both eventually failed past the point of repair. They had seen hard duty over the years with a large microwave carrier in PA and the knobs were literally deteriorating and falling off them. I have test gear, but did not have the experience and skill to keep the best one running. I'll keep looking locally for any I can drive to, but shipping one is going to result in broken parts and failed bite tests.?
?
Thanks for responding.?
?
Jim
Brookline, NH
W3BH
?
?
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Re: HP 141T Power Supply Help Needed
I'd been trying to poke at this between work, so admittedly was a bit distracted.? ? ?I did find the 2n3904 Q10 to be bad and have replaced.?? here is the full supply now that i've had some focus time? Q9..? C = 22v B = 23.5v
E = -15v.?
Q10..
C = 23.6v?
b = 0.007v E = 0v
Q11..?
C= 23.5
B = -.64
E = 0
On Fri, Aug 30, 2024 at 3:56?PM Bill Berzinskas via <bberzinskas= [email protected]> wrote: That does make sense,?thank you for that explanation..? I do believe I've stated it backwards.? ? 22v appears on a 2n3053 that I've replaced at pin 3, which is actually the collector..? :facepalm:..?
Remeasure / restate Q9..? C = 22v B = 23.5v
E = -15v.?
? ??
On Fri, Aug 30, 2024 at 3:02?PM Michael Bafaro via <m.bafaro= [email protected]> wrote: Bill, ? Lets back up a minute¡ If there is +22V at the emitter of the driver Q9 then there must be +22V at the base of the series regulator Q4 and you say that there is less than 1V ?at the emitter of the pass transistor Q4 and also no voltage at the top of R42 (the current sense resistor) then there is 22V across the base emitter junction of? Q4 and that can only be a failed device or some bad wiring or even a cracked runner on the board. A good NPN transistor has no more than 1V Vbe.? ??Does that make sense to you?? Or is the voltage at the emitter of the driver Q9 a negative 22V?? If the voltage at the emitter of Q9 is negative then what is the voltage at the base of Q9? ? Mike ? ? Ok..? I had a few bad transistors in the mix, but the one that was in the unit checks out ok.? ? ?I tossed a small handful to alleviate future issues.? ?
I spent a little time simulating this and from what I'm seeing this almost has to be a problem w/ the voltage divider / potentiometer.? ?I can do a lot of "shady" things in the sim and none of them give me issues like I'm seeing.? ?Removing R43 in the sim, or the pullup R45 seem to skew the voltages like I'm seeing.? ? ?The sim shows that the trimpot is kind of what "kicks things off", and the fact that I'm only getting about -1v here seems to further hint towards R43.? ? I don't have a 22.1k or even a 22k on hand, so I'll probably get creative to see what happens.? ?Resistance measurements on the pot itself look ok, i'm really hoping to not have to yank that thing.?? ? On Fri, Aug 30, 2024 at 11:58?AM Bill Berzinskas via <bberzinskas=[email protected]> wrote: I'll check these over lunch.? ?Interestingly, two of the original transistors in that spot cause the 3a fuse to blow.? ?Now sure if thats indicative of something else going on w/ a good transistor in the seat..? ? tbd.?? ? On Fri, Aug 30, 2024 at 11:43?AM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? 22V on the emitter of the driver is very strange.? It seems that the pass transistor Q2 has an open base ¨C emitter junction and a shorted collector base junction to come up with those voltages.? That would explain the ¡°on output¡± situation.?? An Ohm meter should be sufficient to check the status of Q2.? If your meter has a diode scale, that would give you a quick indication of the status of Q2.? ? I am thinking ?of designing an over voltage crowbar circuit to protect the -12.6 V supply from damaging sensitive circuits down stream of this supply if the regulator goes to an over voltage condition.? Some of the plugins appear to have a crowbar in just such a condition.? The filament of the flood gun is run from the -12.6V and in my case it went over voltage and it burned out the flood gun filament. ? ? Mike ? ? Thanks Michael,?
here's a recap what i'm seeing around the -12.6v line currently:?
?.65v at base of q11 sensor amp, .275v on collector.?? Driver has 22v on emitter, .27v on base and -.27v collector.????? Not much happening on the current limiter.?? 0v base.? ? On Fri, Aug 30, 2024 at 11:15?AM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? OK so you have the early version of the supply.? If you give me the voltages at the base of the driver transistors I can perhaps give you some more pointers. ? Mike ? ? correction, it did have the LAMP..? ?? ? My unit is 1615a prefix, it did have the zener and it was measuring closer to 100v instead of the expected 83 or whatever.? It has since been replaced by a pair of diodes that bring it to 89v but I have had to replace that string at least once in my travels so far, so I will eventually look for a more permanent?solution as I've read about.? ?I can check that again this evening!? ?I stopped thinking about it after I got the?+100v supply up! ? On Thu, Aug 29, 2024 at 4:50?PM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? There are 2 versions of this supply.? There is an early version that has a neon tube as the reference for the +100V supply and a later version that uses a 9V temp compensated Zener that is floating.? That is the reference Zener is connected from the +100V rail and the base of Q4.? It may help to know which version you have.? From my schematic the +100 V is the master and the other supplies are referenced from it.?? The one I have has a serial number prefix 2101A and it appears to be made in the late 1981 or early 1982 time frame. This one has the floating 9V Zener. ? Mike ? ? Finished that up.? ?On the -100 I can adjust up to 96v, a little low but it is adjustable so I think I should come back to that later.??
On 248v I'm currently seeing 290v, and -12v I'm seeing -1.5v.? ? ?I reckon I could go after either of them given the dependencies.? ? Will grab some measurements in between or after work today.? ? ? On Thu, Aug 29, 2024 at 10:52?AM Bill Berzinskas via <bberzinskas=[email protected]> wrote: Well, this is awkward.? ? I had replaced both Diff Amp transistors with the same part number.??
I just found that this package is actually reverse from what i removed!? ?using a dorky little? heathkit transistor tester, i found the pinout to be CBE when looking at it from the flat side.??
The center leg was bent towards the rear of the part, while the original part was bent toward the front.??
I reversed both transistors, and got -106 which i was able to adjust appropriately!? ? ??
Strange, but makes sense.? ?I have a few more of these buggers in the supply, so it sounds like I'll be sorting through that today.? ? Will report back in a bit.??
Thanks for the help ya'll!? ? On Thu, Aug 29, 2024 at 10:45?AM Frank Mashockie via <fmashockie=[email protected]> wrote: Also, don't forget about Gianni's HP e-book.? If I remember correctly, he goes into great detail about the 141T.? Here's the link.? They can be slow to download and I forget which section includes the 141T. ?
|
Re: HP 141T Power Supply Help Needed
That does make sense,?thank you for that explanation..? I do believe I've stated it backwards.? ? 22v appears on a 2n3053 that I've replaced at pin 3, which is actually the collector..? :facepalm:..?
Remeasure / restate Q9..? C = 22v B = 23.5v
E = -15v.?
? ??
On Fri, Aug 30, 2024 at 3:02?PM Michael Bafaro via <m.bafaro= [email protected]> wrote: Bill, ? Lets back up a minute¡ If there is +22V at the emitter of the driver Q9 then there must be +22V at the base of the series regulator Q4 and you say that there is less than 1V ?at the emitter of the pass transistor Q4 and also no voltage at the top of R42 (the current sense resistor) then there is 22V across the base emitter junction of? Q4 and that can only be a failed device or some bad wiring or even a cracked runner on the board. A good NPN transistor has no more than 1V Vbe.? ??Does that make sense to you?? Or is the voltage at the emitter of the driver Q9 a negative 22V?? If the voltage at the emitter of Q9 is negative then what is the voltage at the base of Q9? ? Mike ? ? Ok..? I had a few bad transistors in the mix, but the one that was in the unit checks out ok.? ? ?I tossed a small handful to alleviate future issues.? ?
I spent a little time simulating this and from what I'm seeing this almost has to be a problem w/ the voltage divider / potentiometer.? ?I can do a lot of "shady" things in the sim and none of them give me issues like I'm seeing.? ?Removing R43 in the sim, or the pullup R45 seem to skew the voltages like I'm seeing.? ? ?The sim shows that the trimpot is kind of what "kicks things off", and the fact that I'm only getting about -1v here seems to further hint towards R43.? ? I don't have a 22.1k or even a 22k on hand, so I'll probably get creative to see what happens.? ?Resistance measurements on the pot itself look ok, i'm really hoping to not have to yank that thing.?? ? On Fri, Aug 30, 2024 at 11:58?AM Bill Berzinskas via <bberzinskas=[email protected]> wrote: I'll check these over lunch.? ?Interestingly, two of the original transistors in that spot cause the 3a fuse to blow.? ?Now sure if thats indicative of something else going on w/ a good transistor in the seat..? ? tbd.?? ? On Fri, Aug 30, 2024 at 11:43?AM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? 22V on the emitter of the driver is very strange.? It seems that the pass transistor Q2 has an open base ¨C emitter junction and a shorted collector base junction to come up with those voltages.? That would explain the ¡°on output¡± situation.?? An Ohm meter should be sufficient to check the status of Q2.? If your meter has a diode scale, that would give you a quick indication of the status of Q2.? ? I am thinking ?of designing an over voltage crowbar circuit to protect the -12.6 V supply from damaging sensitive circuits down stream of this supply if the regulator goes to an over voltage condition.? Some of the plugins appear to have a crowbar in just such a condition.? The filament of the flood gun is run from the -12.6V and in my case it went over voltage and it burned out the flood gun filament. ? ? Mike ? ? Thanks Michael,?
here's a recap what i'm seeing around the -12.6v line currently:?
?.65v at base of q11 sensor amp, .275v on collector.?? Driver has 22v on emitter, .27v on base and -.27v collector.????? Not much happening on the current limiter.?? 0v base.? ? On Fri, Aug 30, 2024 at 11:15?AM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? OK so you have the early version of the supply.? If you give me the voltages at the base of the driver transistors I can perhaps give you some more pointers. ? Mike ? ? correction, it did have the LAMP..? ?? ? My unit is 1615a prefix, it did have the zener and it was measuring closer to 100v instead of the expected 83 or whatever.? It has since been replaced by a pair of diodes that bring it to 89v but I have had to replace that string at least once in my travels so far, so I will eventually look for a more permanent?solution as I've read about.? ?I can check that again this evening!? ?I stopped thinking about it after I got the?+100v supply up! ? On Thu, Aug 29, 2024 at 4:50?PM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? There are 2 versions of this supply.? There is an early version that has a neon tube as the reference for the +100V supply and a later version that uses a 9V temp compensated Zener that is floating.? That is the reference Zener is connected from the +100V rail and the base of Q4.? It may help to know which version you have.? From my schematic the +100 V is the master and the other supplies are referenced from it.?? The one I have has a serial number prefix 2101A and it appears to be made in the late 1981 or early 1982 time frame. This one has the floating 9V Zener. ? Mike ? ? Finished that up.? ?On the -100 I can adjust up to 96v, a little low but it is adjustable so I think I should come back to that later.??
On 248v I'm currently seeing 290v, and -12v I'm seeing -1.5v.? ? ?I reckon I could go after either of them given the dependencies.? ? Will grab some measurements in between or after work today.? ? ? On Thu, Aug 29, 2024 at 10:52?AM Bill Berzinskas via <bberzinskas=[email protected]> wrote: Well, this is awkward.? ? I had replaced both Diff Amp transistors with the same part number.??
I just found that this package is actually reverse from what i removed!? ?using a dorky little? heathkit transistor tester, i found the pinout to be CBE when looking at it from the flat side.??
The center leg was bent towards the rear of the part, while the original part was bent toward the front.??
I reversed both transistors, and got -106 which i was able to adjust appropriately!? ? ??
Strange, but makes sense.? ?I have a few more of these buggers in the supply, so it sounds like I'll be sorting through that today.? ? Will report back in a bit.??
Thanks for the help ya'll!? ? On Thu, Aug 29, 2024 at 10:45?AM Frank Mashockie via <fmashockie=[email protected]> wrote: Also, don't forget about Gianni's HP e-book.? If I remember correctly, he goes into great detail about the 141T.? Here's the link.? They can be slow to download and I forget which section includes the 141T. ?
|
Re: HP 141T Power Supply Help Needed
Bill, ? Lets back up a minute¡ If there is +22V at the emitter of the driver Q9 then there must be +22V at the base of the series regulator Q4 and you say that there is less than 1V ?at the emitter of the pass transistor Q4 and also no voltage at the top of R42 (the current sense resistor) then there is 22V across the base emitter junction of? Q4 and that can only be a failed device or some bad wiring or even a cracked runner on the board. A good NPN transistor has no more than 1V Vbe.? ??Does that make sense to you? ?Or is the voltage at the emitter of the driver Q9 a negative 22V?? If the voltage at the emitter of Q9 is negative then what is the voltage at the base of Q9? ? Mike ?
toggle quoted message
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From: [email protected] < [email protected]> On Behalf Of Bill Berzinskas Sent: Friday, August 30, 2024 1:21 PM To: [email protected]Subject: Re: [HP-Agilent-Keysight-equipment] HP 141T Power Supply Help Needed ? Ok..? I had a few bad transistors in the mix, but the one that was in the unit checks out ok.? ? ?I tossed a small handful to alleviate future issues.? ?
I spent a little time simulating this and from what I'm seeing this almost has to be a problem w/ the voltage divider / potentiometer.? ?I can do a lot of "shady" things in the sim and none of them give me issues like I'm seeing.? ?Removing R43 in the sim, or the pullup R45 seem to skew the voltages like I'm seeing.? ? ?The sim shows that the trimpot is kind of what "kicks things off", and the fact that I'm only getting about -1v here seems to further hint towards R43.? ? I don't have a 22.1k or even a 22k on hand, so I'll probably get creative to see what happens.? ?Resistance measurements on the pot itself look ok, i'm really hoping to not have to yank that thing.?? ? On Fri, Aug 30, 2024 at 11:58?AM Bill Berzinskas via <bberzinskas=[email protected]> wrote: I'll check these over lunch.? ?Interestingly, two of the original transistors in that spot cause the 3a fuse to blow.? ?Now sure if thats indicative of something else going on w/ a good transistor in the seat..? ? tbd.?? ? On Fri, Aug 30, 2024 at 11:43?AM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? 22V on the emitter of the driver is very strange.? It seems that the pass transistor Q2 has an open base ¨C emitter junction and a shorted collector base junction to come up with those voltages.? That would explain the ¡°on output¡± situation.?? An Ohm meter should be sufficient to check the status of Q2.? If your meter has a diode scale, that would give you a quick indication of the status of Q2.? ? I am thinking ?of designing an over voltage crowbar circuit to protect the -12.6 V supply from damaging sensitive circuits down stream of this supply if the regulator goes to an over voltage condition.? Some of the plugins appear to have a crowbar in just such a condition.? The filament of the flood gun is run from the -12.6V and in my case it went over voltage and it burned out the flood gun filament. ? ? Mike ? ? Thanks Michael,?
here's a recap what i'm seeing around the -12.6v line currently:?
?.65v at base of q11 sensor amp, .275v on collector.?? Driver has 22v on emitter, .27v on base and -.27v collector.????? Not much happening on the current limiter.?? 0v base.? ? On Fri, Aug 30, 2024 at 11:15?AM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? OK so you have the early version of the supply.? If you give me the voltages at the base of the driver transistors I can perhaps give you some more pointers. ? Mike ? ? correction, it did have the LAMP..? ?? ? My unit is 1615a prefix, it did have the zener and it was measuring closer to 100v instead of the expected 83 or whatever.? It has since been replaced by a pair of diodes that bring it to 89v but I have had to replace that string at least once in my travels so far, so I will eventually look for a more permanent?solution as I've read about.? ?I can check that again this evening!? ?I stopped thinking about it after I got the?+100v supply up! ? On Thu, Aug 29, 2024 at 4:50?PM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? There are 2 versions of this supply.? There is an early version that has a neon tube as the reference for the +100V supply and a later version that uses a 9V temp compensated Zener that is floating.? That is the reference Zener is connected from the +100V rail and the base of Q4.? It may help to know which version you have.? From my schematic the +100 V is the master and the other supplies are referenced from it.?? The one I have has a serial number prefix 2101A and it appears to be made in the late 1981 or early 1982 time frame. This one has the floating 9V Zener. ? Mike ? ? Finished that up.? ?On the -100 I can adjust up to 96v, a little low but it is adjustable so I think I should come back to that later.??
On 248v I'm currently seeing 290v, and -12v I'm seeing -1.5v.? ? ?I reckon I could go after either of them given the dependencies.? ? Will grab some measurements in between or after work today.? ? ? On Thu, Aug 29, 2024 at 10:52?AM Bill Berzinskas via <bberzinskas=[email protected]> wrote: Well, this is awkward.? ? I had replaced both Diff Amp transistors with the same part number.??
I just found that this package is actually reverse from what i removed!? ?using a dorky little? heathkit transistor tester, i found the pinout to be CBE when looking at it from the flat side.??
The center leg was bent towards the rear of the part, while the original part was bent toward the front.??
I reversed both transistors, and got -106 which i was able to adjust appropriately!? ? ??
Strange, but makes sense.? ?I have a few more of these buggers in the supply, so it sounds like I'll be sorting through that today.? ? Will report back in a bit.??
Thanks for the help ya'll!? ? On Thu, Aug 29, 2024 at 10:45?AM Frank Mashockie via <fmashockie=[email protected]> wrote: Also, don't forget about Gianni's HP e-book.? If I remember correctly, he goes into great detail about the 141T.? Here's the link.? They can be slow to download and I forget which section includes the 141T. ?
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Re: 16901A 16901-14102 recovery disc ISO wanted (was Re: [HP-Agilent-Keysight-equipment] Wanted: 16902B recovery DVD, p/n 16902-14100)
On Fri, Aug 30, 2024, 12:22 Dr. David Kirkby, Kirkby Microwave Ltd via <drkirkby= [email protected]> wrote: I would suggest trying wget, curl, or at a time when the majority of people in the USA
Using wget, it took about 36 hours to download the 200GB tarball over gigabit fiber. My second downloaded was via torrent, which has error checking. That took about four hours, and the results was identical. That's why I'm fairly sure that the IA archived copy of 14901-14102.iso is corrupt.
I don't think more people trying to download it is going to help. That said, if anyone else does download it, we can compare sha256sum of the overall archive, or the individual .iso images.
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Re: 16901A 16901-14102 recovery disc ISO wanted (was Re: [HP-Agilent-Keysight-equipment] Wanted: 16902B recovery DVD, p/n 16902-14100)
If someone wants to send me a URL, I could try pulling the file from a fast connection.
Thanks, but both of my downloads of 16901-14102.iso from IA were done over gigabit fiber. That's not the limiting factor. Also, I have with very high confidence determined that the IA copy is corrupt, hence my request to anyone who might have the physical DVD.
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Re: 16901A 16901-14102 recovery disc ISO wanted (was Re: [HP-Agilent-Keysight-equipment] Wanted: 16902B recovery DVD, p/n 16902-14100)
If someone wants to send me a URL, I could try pulling the file from a fast connection.
Unfortunately is slow, so irrespective of what speed you have, you are not going to be able to download it quickly.
I would suggest trying wget, curl, or at a time when the majority of people in the USA are asleep. I believe that internet traffic is lower at those times, so I guess speeds might go up.?
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Re: HP 141T Power Supply Help Needed
Ok..? I had a few bad transistors in the mix, but the one that was in the unit checks out ok.? ? ?I tossed a small handful to alleviate future issues.? ?
I spent a little time simulating this and from what I'm seeing this almost has to be a problem w/ the voltage divider / potentiometer.? ?I can do a lot of "shady" things in the sim and none of them give me issues like I'm seeing.? ?Removing R43 in the sim, or the pullup R45 seem to skew the voltages like I'm seeing.? ? ?The sim shows that the trimpot is kind of what "kicks things off", and the fact that I'm only getting about -1v here seems to further hint towards R43.? ? I don't have a 22.1k or even a 22k on hand, so I'll probably get creative to see what happens.? ?Resistance measurements on the pot itself look ok, i'm really hoping to not have to yank that thing.??
On Fri, Aug 30, 2024 at 11:58?AM Bill Berzinskas via <bberzinskas= [email protected]> wrote: I'll check these over lunch.? ?Interestingly, two of the original transistors in that spot cause the 3a fuse to blow.? ?Now sure if thats indicative of something else going on w/ a good transistor in the seat..? ? tbd.??
On Fri, Aug 30, 2024 at 11:43?AM Michael Bafaro via <m.bafaro= [email protected]> wrote: Bill, ? 22V on the emitter of the driver is very strange.? It seems that the pass transistor Q2 has an open base ¨C emitter junction and a shorted collector base junction to come up with those voltages.? That would explain the ¡°on output¡± situation.?? An Ohm meter should be sufficient to check the status of Q2.? If your meter has a diode scale, that would give you a quick indication of the status of Q2.? ? I am thinking ?of designing an over voltage crowbar circuit to protect the -12.6 V supply from damaging sensitive circuits down stream of this supply if the regulator goes to an over voltage condition.? Some of the plugins appear to have a crowbar in just such a condition.? The filament of the flood gun is run from the -12.6V and in my case it went over voltage and it burned out the flood gun filament. ? ? Mike ? ? Thanks Michael,?
here's a recap what i'm seeing around the -12.6v line currently:?
?.65v at base of q11 sensor amp, .275v on collector.?? Driver has 22v on emitter, .27v on base and -.27v collector.????? Not much happening on the current limiter.?? 0v base.? ? On Fri, Aug 30, 2024 at 11:15?AM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? OK so you have the early version of the supply.? If you give me the voltages at the base of the driver transistors I can perhaps give you some more pointers. ? Mike ? ? correction, it did have the LAMP..? ?? ? My unit is 1615a prefix, it did have the zener and it was measuring closer to 100v instead of the expected 83 or whatever.? It has since been replaced by a pair of diodes that bring it to 89v but I have had to replace that string at least once in my travels so far, so I will eventually look for a more permanent?solution as I've read about.? ?I can check that again this evening!? ?I stopped thinking about it after I got the?+100v supply up! ? On Thu, Aug 29, 2024 at 4:50?PM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? There are 2 versions of this supply.? There is an early version that has a neon tube as the reference for the +100V supply and a later version that uses a 9V temp compensated Zener that is floating.? That is the reference Zener is connected from the +100V rail and the base of Q4.? It may help to know which version you have.? From my schematic the +100 V is the master and the other supplies are referenced from it.?? The one I have has a serial number prefix 2101A and it appears to be made in the late 1981 or early 1982 time frame. This one has the floating 9V Zener. ? Mike ? ? Finished that up.? ?On the -100 I can adjust up to 96v, a little low but it is adjustable so I think I should come back to that later.??
On 248v I'm currently seeing 290v, and -12v I'm seeing -1.5v.? ? ?I reckon I could go after either of them given the dependencies.? ? Will grab some measurements in between or after work today.? ? ? On Thu, Aug 29, 2024 at 10:52?AM Bill Berzinskas via <bberzinskas=[email protected]> wrote: Well, this is awkward.? ? I had replaced both Diff Amp transistors with the same part number.??
I just found that this package is actually reverse from what i removed!? ?using a dorky little? heathkit transistor tester, i found the pinout to be CBE when looking at it from the flat side.??
The center leg was bent towards the rear of the part, while the original part was bent toward the front.??
I reversed both transistors, and got -106 which i was able to adjust appropriately!? ? ??
Strange, but makes sense.? ?I have a few more of these buggers in the supply, so it sounds like I'll be sorting through that today.? ? Will report back in a bit.??
Thanks for the help ya'll!? ? On Thu, Aug 29, 2024 at 10:45?AM Frank Mashockie via <fmashockie=[email protected]> wrote: Also, don't forget about Gianni's HP e-book.? If I remember correctly, he goes into great detail about the 141T.? Here's the link.? They can be slow to download and I forget which section includes the 141T. ?
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Re: 16901A 16901-14102 recovery disc ISO wanted (was Re: [HP-Agilent-Keysight-equipment] Wanted: 16902B recovery DVD, p/n 16902-14100)
If someone wants to send me a URL, I could try pulling the file from a fast connection.
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Keith Monahan
Jim Sorenson
Dr. David Kirkby, Kirkby Microwave Ltd