Re: Farewell Keysight Marketing.
This was done many years ago when there was some (small) benefit to Keysight.? When it started off, it hadn't achieved the peak of success it has today.? Much of the (clause 4J) I didn't know of. Naturally, when they waved a 3000 dollar oscilloscope at me, I just looked at my Tektronix 7904 and decided that I wouldn't buy. They've even stopped the "scope give away, which unaccountably never mentioned my name as a winner.
For some reason, if TEK does have a list, I never got on it.
I tend to either get equipment I can repair, or equipment that is essentially "use until breaks" and then if "cannot get the parts or fix it" then replace (if desirable).
Harvey
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On 9/6/2024 6:13 PM, Matt Harris wrote: People actually intentionally want to receive email spam to begin with?
|
dear Yves, I didn't realize that you had made the measurements expressly to help me! I owe you then a double (even triple) thanks! Especially considering the fact that the front end of this instrument is really very dense, complicated and delicate!
After my last email, in addition to doing the (essentially mechanical) intervention on the SYTF, I continued to check the input signal through the various sections by alternately injecting 300MHz @-20dBm and 5GHz @0 dBm
The signals were found to be in specification up to the A3A9 bandpass (where the two paths join to form the intermediate frequency of 321.4MHz). At this point I could see the 5GHz signal (converted), present at that point at -47dBm (the specification says -43/-56dBm).
Instead, no trace of the 300MHz input signal
Investigatine?the second converter A3A4 in more depth
I checked?the signals at its input
On J1 there is 3.9214GHz at -46dBm? --->OK
On J3 there is 321.4MHz @ -37.7dBm? --->OK
On J4 I did not check 600MHz @-1dBm but the fact that the converter works in band 1 tells me that the oscillator is present and is in specification
The power supply is quite OK (5V are actually 4.75; 10V are 9.98 and the DC that controls the internal switch that should be +15V? (band 0) and -3.5V?(band 1) is actually +14.60V and -1.35V
?
This last value is rather far from the nominal and would have worried me BUT band 1 is exactly the one that works
Conclusion: it would seem that the culprit is the second converter and in particular (probably) the internal switch that has the sole task of letting the signal? (which is already at 321.4MHz and does not need to be converted)?pass from its input to the output
In the next few days I will test the converter that meanwhile?has been?disassembled?; In the meantime I found a cheap one on the bay that should arrive in about ten days
Yves, I have a question: on the block diagram A3A4 is represented as a block that has 5 ports of which one (J5) would seem to be the connector that carries the power and the DC that controls the switch and that connects to A7 Analog Interface through the W35 cable
?
Actually,?this connector on the real component, does not have a name
Instead,?the name J5?, stamped on the case , indicates an SMB connector that has the writing LO TEST and in my analyzer?it is the one that?conveys the 600MHz LO signal?
Now,?on the block diagram the connector that conveys the 600MHz signal has the name J4 (in my analyzer, the J4 connector was disconnected)
?
This confusion of names and roles made me doubt that years ago, when I had disassembled this section I had not reassembled it correctly
thanks again and best regards
Adri
?
?
?
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----- Messaggio originale -----
Inviato: 06/09/2024 23:21:52
Oggetto: Re: [HP-Agilent-Keysight-equipment] HP 5086-7906 YTO
Hi Adri,
?
I had sent you the measurements of the RF input-output mixer signals verification, I had disassembled the High Frequency section of my 8595E to be able to provide you with this information.
If you have no more questions relating to this section, I will close my 8595E and do a flatness check to see if everything is correct.
?
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
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Re: HP 141T Power Supply Help Needed
Thanks for sharing that tip!? ? Will pick one up.? ??
I removed and reflowed the board yesterday.? Things changed slightly. Haven't had a chance to look at your last comments but i will get back to it tonight and report back?
Bill, ? A buddy of mine brought over his 141T and the -100V was missing and all of the small signal transistor were working OK but the pass transistor was not conducting.? I tapped the pass transistor and it started working¡? So I removed the two screws that hold the TO3 transistor in and it just about fell out of the socket.? It had ZERO insertion force!! The socket is bad which is a pain to get to but I pulled it out thinking I could squeeze the socket pins together and fix the problem, but the pins were so soft that after I put the transistor back in it still had almost no insertion force.? To make it reliable I have ordered some new sockets form Mouser. The are part number 4608 by Keystone Electronics for about $2.20 each.?? Hard to believe that the sockets are still available even if the 2N3055s and gone! ? Mike ? ? Bill, ? Since the driver is in saturation, Vce is almost 0V then it seems you may have a wiring problem.? Check the voltage across R40.? That should be about 22-24VDC.? If not check the voltage at C6 which is a big can lytic on top of the unit.? Also the wiring to and from the rectifiers CR1 and CR2.? The anodes of the two diodes should have about 24VAC. Or the fuse F4 is open.? There is not much left.? The error amp seems to be working.? Let me know what you find. ? Mike ? ? Mike,?
I now get a rather high impedance?at the output of the regulator, think it was ~50k.? ? ?The previous issue was in fact a physical short on A5 board (lead clipping...)
Currently, things look as follows:?
Q9
C .65?
B? 1.36
E .65
Q10?
C 2.4
B 0
E 0
Q11
C 1.3
B -.65
E 0?
Output Voltage -0.002
Output Impedance? ~400k? I get the sneaking suspicion that my driver is bad as the CE voltages are roughly equivalent (maybe .002 different).? ? ?The voltage I see at the base of Q9 seems close, so I'm guessing the sensor amp is working better..? ?Q10 base at 0v is a little weird.? ?
Like I say, I'll go back through things this afternoon and see if any remaining parts saw issues in the last round of testing.? ? ?This feels like progress though.? ? ?
I don't know how to fix Q4 socket long term, but I'm mulling that over.? I kind of want to insert / solder a pin in place of the spring contacts that have been causing me so much frustration.? ? ? ? On Thu, Sep 5, 2024 at 10:42?AM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? The big question is what resistance do you measure at the pins of the A2 board that have the white / Violet wires going to them with the wires removed.? At this point you should read >1K Ohm at the output of the regulator.? If the resistance at the output of the regulator is < 4 Ohms don¡¯t put in a new pass device.? As I remember you had one of the white / violet wires that measured < 1 Ohm.? I seem to remember that you were going to trace out that wire to see where it went and why it read so low.? ?I remember you had one of the White / violet wires that went to the A5 assembly which runs the storage functions and you were going to find the cause of that later.? Let me know what you find. ? Mike ? ? Ugh, I put it down for a few days to work on an old Zenith my wife got for my birthday.? Today, I put a fresh pass trans in, and fired it up.? I got -2.5v for a few seconds and then it looks like it took out the transistor.? Replaced and same story.? ? ? Mike - with F4 removed, I measure ~50k ohm at the terminal you mention, so that rules out C9?? ? R49 does look ok..? my DMM only measures tenths, so I get a floating .2 to .3 ohm.? I guess I typo¡¯d the decimal or mentally transcribed wrong.. ?
Dave - I ran through each part you mention.? R44 was a little suspect in that the schematic says 20k but it measured 18k, still in range but I¡¯d have expected it to go UP. ? In a fit of rage, I replaced C8, C9 , R44, R46 and still blows pass trans.? ? ?Raw voltage in??is around 22v last I checked.
At this point, I¡¯m wondering if there is something under the board fighting me. ? It didn¡¯t look like I was the first person in here, and I¡¯ve been working from the top side only.? ? Is it worth pulling the board to look at? ? ? I could go eBay a bunch of old exotic parts, I could try to shotgun some moremodern parts in.. ? ? I do feel like I¡¯m loosing the battle on this rail though. ? Anyone in North Carolina?? :-)? ? Hello All
I have a hp 141t when it is powered up there is no trace but when I turn off the power the trace briefly appears in top right corner.
Is it the blanking circuit or do I need to do an trace? alignment or something else. I need some guidance
Has anyone encountered this problem before and let me know what you did.
73's Leroy de VK5HL
-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Chuck Harris
Sent: Tuesday, 3 September 2024 1:41 PM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP 141T Power Supply Help Needed
To amplify your comment, many times older linear supplies, when they are brute force recapped, with the best, long life, low esr caps you can find, will become beacons of chaotic oscillation.
I put a low ESR ceramic capacitor in the feedback loop of a unity gain OPAMP circuit the other day, and was amazed that it went totally unstable.? It was an older LM301 variety, where the response characteristics of the opamp are a blank slate until the designer adds in the stability network.? The designer's efforts were wiped out by my ceramic capacitor replacement for his 1uf back-to-back emulation of a non-polar electrolytic.
Sometimes the modern best replacement is not suitable for use in an older instrument.
-Chuck Harris
On Mon, 2 Sep 2024 22:40:20 +0100 "Dave_G0WBX via "
<g8kbvdave=[email protected]> wrote:
> Hi.
>
> It's just a generic term (damping is another) to slow down the
> response of a loop, to prevent it going unstable.
>
> Not an uncommon issue in some linear PSU's like those -12.6V or -100V
> regulator topologies that are not "conventionally" laid out.
>
> Unless you 'scope the thing, you often don't know it's gone unstable,
> other than some passive parts sometimes cook for no obvious reason.
> (That R49 for example!? See Mike's comment in another mail.)
>
> It is also not uncommon, when modern transistors are used to replace
> older failed parts (that are not available any more) and the new
> device has "a lot" more gain at HF than the originals, that regulator
> or other control loops suddenly become "unruly" under some operating
> conditions.
>
> Sometimes a low value "Base Stopper" resistor (a few Ohms, or a
> ferrite bead) in series with the new device's Base connection can
> restore sanity!
>
> Take care.
>
> Dave B.
>
>
>
|
Re: HP 141T Power Supply Help Needed
Bill, ? A buddy of mine brought over his 141T and the -100V was missing and all of the small signal transistor were working OK but the pass transistor was not conducting.? I tapped the pass transistor and it started working¡? So I removed the two screws that hold the TO3 transistor in and it just about fell out of the socket.? It had ZERO insertion force!! The socket is bad which is a pain to get to but I pulled it out thinking I could squeeze the socket pins together and fix the problem, but the pins were so soft that after I put the transistor back in it still had almost no insertion force.? To make it reliable I have ordered some new sockets form Mouser. The are part number 4608 by Keystone Electronics for about $2.20 each.?? Hard to believe that the sockets are still available even if the 2N3055s and gone! ? Mike ?
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From: [email protected] < [email protected]> On Behalf Of Michael Bafaro via groups.io Sent: Thursday, September 5, 2024 3:19 PM To: [email protected]Subject: Re: [HP-Agilent-Keysight-equipment] HP 141T Power Supply Help Needed ? Bill, ? Since the driver is in saturation, Vce is almost 0V then it seems you may have a wiring problem.? Check the voltage across R40.? That should be about 22-24VDC.? If not check the voltage at C6 which is a big can lytic on top of the unit.? Also the wiring to and from the rectifiers CR1 and CR2.? The anodes of the two diodes should have about 24VAC. Or the fuse F4 is open.? There is not much left.? The error amp seems to be working.? Let me know what you find. ? Mike ? ? Mike,?
I now get a rather high impedance?at the output of the regulator, think it was ~50k.? ? ?The previous issue was in fact a physical short on A5 board (lead clipping...)
Currently, things look as follows:?
Q9
C .65?
B? 1.36
E .65
Q10?
C 2.4
B 0
E 0
Q11
C 1.3
B -.65
E 0?
Output Voltage -0.002
Output Impedance? ~400k? I get the sneaking suspicion that my driver is bad as the CE voltages are roughly equivalent (maybe .002 different).? ? ?The voltage I see at the base of Q9 seems close, so I'm guessing the sensor amp is working better..? ?Q10 base at 0v is a little weird.? ?
Like I say, I'll go back through things this afternoon and see if any remaining parts saw issues in the last round of testing.? ? ?This feels like progress though.? ? ?
I don't know how to fix Q4 socket long term, but I'm mulling that over.? I kind of want to insert / solder a pin in place of the spring contacts that have been causing me so much frustration.? ? ? ? On Thu, Sep 5, 2024 at 10:42?AM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? The big question is what resistance do you measure at the pins of the A2 board that have the white / Violet wires going to them with the wires removed.? At this point you should read >1K Ohm at the output of the regulator.? If the resistance at the output of the regulator is < 4 Ohms don¡¯t put in a new pass device.? As I remember you had one of the white / violet wires that measured < 1 Ohm.? I seem to remember that you were going to trace out that wire to see where it went and why it read so low.? ?I remember you had one of the White / violet wires that went to the A5 assembly which runs the storage functions and you were going to find the cause of that later.? Let me know what you find. ? Mike ? ? Ugh, I put it down for a few days to work on an old Zenith my wife got for my birthday.? Today, I put a fresh pass trans in, and fired it up.? I got -2.5v for a few seconds and then it looks like it took out the transistor.? Replaced and same story.? ? ? Mike - with F4 removed, I measure ~50k ohm at the terminal you mention, so that rules out C9?? ? R49 does look ok..? my DMM only measures tenths, so I get a floating .2 to .3 ohm.? I guess I typo¡¯d the decimal or mentally transcribed wrong.. ?
Dave - I ran through each part you mention.? R44 was a little suspect in that the schematic says 20k but it measured 18k, still in range but I¡¯d have expected it to go UP. ? In a fit of rage, I replaced C8, C9 , R44, R46 and still blows pass trans.? ? ?Raw voltage in??is around 22v last I checked.
At this point, I¡¯m wondering if there is something under the board fighting me. ? It didn¡¯t look like I was the first person in here, and I¡¯ve been working from the top side only.? ? Is it worth pulling the board to look at? ? ? I could go eBay a bunch of old exotic parts, I could try to shotgun some moremodern parts in.. ? ? I do feel like I¡¯m loosing the battle on this rail though. ? Anyone in North Carolina?? :-)? ? Hello All
I have a hp 141t when it is powered up there is no trace but when I turn off the power the trace briefly appears in top right corner.
Is it the blanking circuit or do I need to do an trace? alignment or something else. I need some guidance
Has anyone encountered this problem before and let me know what you did.
73's Leroy de VK5HL
-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Chuck Harris
Sent: Tuesday, 3 September 2024 1:41 PM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP 141T Power Supply Help Needed
To amplify your comment, many times older linear supplies, when they are brute force recapped, with the best, long life, low esr caps you can find, will become beacons of chaotic oscillation.
I put a low ESR ceramic capacitor in the feedback loop of a unity gain OPAMP circuit the other day, and was amazed that it went totally unstable.? It was an older LM301 variety, where the response characteristics of the opamp are a blank slate until the designer adds in the stability network.? The designer's efforts were wiped out by my ceramic capacitor replacement for his 1uf back-to-back emulation of a non-polar electrolytic.
Sometimes the modern best replacement is not suitable for use in an older instrument.
-Chuck Harris
On Mon, 2 Sep 2024 22:40:20 +0100 "Dave_G0WBX via "
<g8kbvdave=[email protected]> wrote:
> Hi.
>
> It's just a generic term (damping is another) to slow down the
> response of a loop, to prevent it going unstable.
>
> Not an uncommon issue in some linear PSU's like those -12.6V or -100V
> regulator topologies that are not "conventionally" laid out.
>
> Unless you 'scope the thing, you often don't know it's gone unstable,
> other than some passive parts sometimes cook for no obvious reason.
> (That R49 for example!? See Mike's comment in another mail.)
>
> It is also not uncommon, when modern transistors are used to replace
> older failed parts (that are not available any more) and the new
> device has "a lot" more gain at HF than the originals, that regulator
> or other control loops suddenly become "unruly" under some operating
> conditions.
>
> Sometimes a low value "Base Stopper" resistor (a few Ohms, or a
> ferrite bead) in series with the new device's Base connection can
> restore sanity!
>
> Take care.
>
> Dave B.
>
>
>
|
Re: Farewell Keysight Marketing.
Advertising has become the be all and end all of media of all types. Too much advertising. Much of it done badly, like bill boards. If you must look at one twice to get the message its a failure.
If not for advertising most print media, broadcasting, the internet would go away. Might be a good thing. Most graffiti is just advertising. When dogs mark their territory it amounts to advertising.
What does that have to do with electronic measurement?
My excuse is that its 111F here. Not advertising. The real thing.
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On 9/6/2024 3:13 PM, Matt Harris wrote: People actually intentionally want to receive email spam to begin with?
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
|
Re: 8566B attenuator removal
I did actually post pictures of what I was seeing on each of the settings on another related thread message #146621.? Having now taken a second look at those pictures however, I have noticed they were indeed at 1dB/div on the vertical scale so I shall have to re-do them on 10dB/div for the sake of clarity.
Sigh... Sunday I have some time available so will remove the attenuator and inspect its internals. I may post some photos of it's innards once that's been done.
I have to say I'm becoming rather more intimately acquainted with the guts of this analyzer than I'd ever imagined!
|
Re: Farewell Keysight Marketing.
People actually intentionally want to receive email spam to begin with?
|
Re: Leaking alkaline cells
So I was obviously wrong about my comment that Zinc Carbon batteries don't leak, and I did some "research" (aka found my box of dead batteries, took some pictures, and used google translate). The super light batteries that don't leak that come with remotes I was thinking of are Manganese batteries apparently, and they are marked "DRY BATTERY" on them. It's quite possible that I've never actually seen a Zinc Carbon battery in real life, as these are the ones I always thought were Zinc Carbon. I know some people say the Zinc Carbon are marked "Heavy Duty" as this one is, and I jumped to the wrong conclusion.
On Fri, Sep 6, 2024 at 1:00?PM Adrian Godwin via <artgodwin= [email protected]> wrote: I have a 3D maglite that was badly corroded by energisers (though, I'm not sure if UK energisers are the same as US ones). After cleaning it out iot wasn't too bad, just some roughness on the internal surface. The corrosion was in the middle and hadn't reached the switch or cap.
?
I replaced with Nicad obtained somewhere cheaply (but new, decent industrial ones, probably intended for emergency light backup). This would have resulted in dim light but I also replaced the bulb with an LED one with a switching regulator making it insensitive to low batteries. The result is pretty good.
?
Another way to get around low voltage cells is the batteriser boost regulator. They don't extend battery life anywhere near as long as claimed and aren't very useful for modern devices that can tolerate low voltage, but they will bring nicads/NiMH up to alkaline levels, useful for fussy older devices. The downside is they will try to suck every joule out of the cell - not the best way to look after rechargeables. I believe they now have a version that cuts out at NiMH end voltage.
?
For PP3s, there are some lipo-based versions with a USB C charging port. These give full 9V, unlike earlier NiMH which were low voltage (though some had 7 cells instead of 6 to compensate). I've got a couple of these lithium ones and am so far pleased with them but haven't done a long-term test.
?
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Re: Free to good home, HP 5423A system + manuals and spares
On 9/5/24 14:01, Tam Hanna wrote: due to ill fortune, I have an US address now.
If there are no takers and you are willing to ship domestically, let me
know. You're based in the US now?? -Dave -- Dave McGuire, AK4HZ New Kensington, PA
|
Re: FW: HP 141T NO TRACE AFTER POWER UP
Leroy,
?
It would be helpful to get some information to help you.? Is this symptom occurring with the plug-in installed or without?? Do you see the trace when depress the beam finder???
?
If you still have the plug-in installed (whether that be an SA or oscilloscope), I would remove it.? Confirm that the 141T is good.? Check your LV and HV voltage rails - make sure they are inspect.? You'll have to confirm all that first anyway before troubleshooting the blanking circuit.
?
Let us know what you find.
?
-Frank
|
Re: FW: HP 141T NO TRACE AFTER POWER UP
Leroy, ? The first thing I would do is check to see that all of the basic supply voltages are in spec.? Also check to see that the base line clipper is fully CCW.? I would put in the calibrator signal into the RF input and tune to about 30MHz.? Let us know what happens. ? Mike ?
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Show quoted text
From: [email protected] <[email protected]> On Behalf Of VK5HL
Sent: Friday, September 6, 2024 11:23 AM
To: [email protected]
Subject: [HP-Agilent-Keysight-equipment] FW: HP 141T NO TRACE AFTER POWER UP? ? ? ? Hello All ? I have a hp 141t when it is powered up there is no trace but when I turn off the power the trace briefly appears in top right corner. Is it the blanking circuit or do I need to do an trace? alignment or something else. I need some guidance ? Has anyone encountered this problem before and let me know what you did. ? ? 73's Leroy de VK5HL ?
|
Hi Adri, ? I had sent you the measurements of the RF input-output mixer signals verification, I had disassembled the High Frequency section of my 8595E to be able to provide you with this information. If you have no more questions relating to this section, I will close my 8595E and do a flatness check to see if everything is correct. ? 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
|
Re: FW: HP 141T NO TRACE AFTER POWER UP
Checked the deflection plate voltages?
|
Re: 8566B attenuator removal
Jinxie, here is my guess as to what is wrong with the attenuator. Below is part of your post from a previous thread.
?
This attenuator has three sections, 10, 20, and 40dB. Each section is either in line or it's bypassed. Various combinations of these three values will give 0-70dB in 10dB steps. Ignoring your measurements at 60 and 70dB for a moment, it looks like 50, 40, 30? and 20 are switching in and out correctly. The 10dB section is not properly bypassed in the 0dB setting. It's also not in-line in the 10dB setting. Thereffore:
?
- One or both plungers in the 10dB section are not working, likely because of one or more bad/missing o-rings.
- The solenoid logic is not working. If this attenuator has the mechanical logic, I would look at the Y-contacts.
?
You can determine if the solenoid is doing anything by listening for clicks when going between 0 and 10dB. Also listen for the type of sound when comparing the non-working 10dB section to another (working) section.
?
Regarding your 60 and 70dB observations, you don't say if you left the display in the 1dB/div setting, or if you changed to 10dB/div. You also don't say where on the screen the noise is. If you were observing with a 10/ vertical scale, and the noise was way down, then this would confirm that the path through the 10dB section is interrupted while in the 70dB setting. Similarly, if the 60dB setting shows noise near the bottom of the screen, that would imply that the path around the 10dB section is also open.
?
You can repeat these experiments by recallung reg. 8 and then changing the scale to 10dB/div. It's usually better to post pictures than to give verbal descriptions.
?
Vladan
?
At 70dB, I'm seeing just massive noise.
At 60dB, occasional noise fickers
At 50dB, I see a thick, fuzzy arch
At 40dB, I see a less fuzzy arch
At 30dB, I see a nice, clean arch
At 20dB, I see a nice clean arch of almost the same amplitude as with 30dB.
At 10dB, I see nothing
At 0dB, I again see nothing.
|
Re: Leaking alkaline cells
I have a 3D maglite that was badly corroded by energisers (though, I'm not sure if UK energisers are the same as US ones). After cleaning it out iot wasn't too bad, just some roughness on the internal surface. The corrosion was in the middle and hadn't reached the switch or cap.
?
I replaced with Nicad obtained somewhere cheaply (but new, decent industrial ones, probably intended for emergency light backup). This would have resulted in dim light but I also replaced the bulb with an LED one with a switching regulator making it insensitive to low batteries. The result is pretty good.
?
Another way to get around low voltage cells is the batteriser boost regulator. They don't extend battery life anywhere near as long as claimed and aren't very useful for modern devices that can tolerate low voltage, but they will bring nicads/NiMH up to alkaline levels, useful for fussy older devices. The downside is they will try to suck every joule out of the cell - not the best way to look after rechargeables. I believe they now have a version that cuts out at NiMH end voltage.
?
For PP3s, there are some lipo-based versions with a USB C charging port. These give full 9V, unlike earlier NiMH which were low voltage (though some had 7 cells instead of 6 to compensate). I've got a couple of these lithium ones and am so far pleased with them but haven't done a long-term test.
?
|
Re: Leaking alkaline cells
Over 400 scanned 1902-2016 issues are here:
On 9/5/24 18:16, Peter Gottlieb wrote:
> Yeah but they had those neat carbon rods that could be used for other things.
Yeah, all kinds of fun experiments from Popular mechanics of the 30s 40s....
The DIY "no transformer required" carbon arc welder was my favorite read.? ?Did a mild test of it, but no steel welding.
|
HP 8568B from hell to Heaven... a restoration story!
Good evening, my name is Andrea, and I live in Florence, Italy. I want to tell you the story of the restoration of an HP 8568B spectrum analyzer that I recently purchased.
While I was searching online for spare parts for the 8568B I already own, which is in perfect working condition (it¡¯s always useful to have spare parts just in case), I came across an auction for an 8568B in Estonia. The seller was offering three available RF units, specifying that they were all incomplete, without covers, and intended for spare parts. In a separate listing, he was selling 85662A displays, also faulty, incomplete, and missing some parts. He didn¡¯t allow buyers to choose which one from the batch would be shipped.
The price was extraordinarily low, so I thought that whatever gets shipped would still exceed the value of the auction. So, I bought a display and an RF unit. About 15 days later, the courier arrived. I was horrified! The seller had wrapped everything in a single layer of very light bubble wrap and covered it with a black bag. No protection, no box.
When I opened the packages, there were loose boards inside, screws with no apparent origin, and the display unit¡¯s frame was broken. But miraculously, the CRT seemed intact...
To be continued...
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Re: 8566B attenuator removal
FWIW I had a faulty section in one of these style of attenuators,
when I took it apart there was some corrosion around one of the
resistor chips where it was grounded to the aluminium body, cleaned
it up and it's been fine for (some years) since.
As Ozan says, dig in to it and see what you find, you may be lucky!
On 06/09/2024 19:03, Ozan wrote:
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Hi Jinxie,
If 0dB attenuation was damaged because of over voltage it
would have damaged a lot more. It is very likely some mechanical
problem like sticky o-rings. Your phase detector repair was a
lot more complex, why don't you try repairing the attenuator
first? Worst case is you need a new one so nothing to lose. It
may be obvious but I will mention it: Once attenuator is out can
test it with a DVM by terminating to 50-ohms at DVM and applying
DC voltage. Just do 20*log(Vo/Vi). This attenuator doesn't have
a DC block in it so DC would work.?
Ozan
?
?
On Fri, Sep 6, 2024 at 10:14 AM, Jinxie wrote:
Hi Vladan,
?
Many thanks indeed for your observations. I was certainly
aware that the Analyzer would no longer 'know' what level of
attenuation was being applied to the source RF and that I
would have to manually account for it, but provided that
doesn't put any of the downstream circuitry at risk of
damage, it's an inconvenience I may have no alternative but
to live with.
This SA was owned by an RF engineer and I purchase it
from him about 10 years ago along with a faulty
Marconi/Aeroflex RF signal generator with a disclosed fault.
No faults were disclosed in regards to the SA, however. The
sig gen I was able to repair and it's a valuable item of
equipment to have for all sorts of reasons. Anyway the fact
that the seller disclosed the sig gen fault leads me to
believe he was honest and was unaware of any issue with the
SA. However, I've never done anything with that SA which
could burn out the 0 and 10dB settings either, having used
it solely for monitoring the RF environment around me using
a short telescopic antenna, so no physical connection to the
RF input.
As I mentioned, I do have an HP 8495K 0-70dB attenuator
which might save the day. I don't think there are any issues
with that. However, it's NOT the same type as the one in the
8566B...
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Re: Leaking alkaline cells
On Friday 06 September 2024 12:27:03 am tgerbic wrote: I worry about battery leakage as well and have not found a battery brand today that does not leak. I do remember some brands back in the 60s or 70s did not seem to leak but things escalated over the decades to all brands seem to leak. I think it has reached a point where companies just expect that consumers assume all batteries leak so not much consumers can do about it.
Quality in general is not really a high
With that said, I bought a bunch of old Heathkit gear filled with the old Radio Shack C batteries about 8 years ago, perhaps two dozen batteries were removed. As expected they were all dead batteries but every one was in pristine condition, almost looked clean enough to eat off of. Not even a hint of leakage. I know they were probably 20 years old but but it was almost unbelievable.? So it is possible to make non-leaking batteries but probably cost prohibitive today. I have a 2-D-cell magliight that lives on my night table. It occurred to me recently that those batteries had been in there a *LONG* time. I picked it up and tried it out, no light, so I took the batteries out. Tested them, and they read like new. Duracell brand, marked "MAR 2013" on them. And absolutely no signs of leakage. I have had some issues with their AA cells, though. I've tried many store brands, HF and dollar stores and others. They just don't seem to last as long as the name brand stuff in my experience. These days I buy mostly Energizers... -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin
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Re: 8566B attenuator removal
Hi Jinxie,
If 0dB attenuation was damaged because of over voltage it would have damaged a lot more. It is very likely some mechanical problem like sticky o-rings. Your phase detector repair was a lot more complex, why don't you try repairing the attenuator first? Worst case is you need a new one so nothing to lose. It may be obvious but I will mention it: Once attenuator is out can test it with a DVM by terminating to 50-ohms at DVM and applying DC voltage. Just do 20*log(Vo/Vi). This attenuator doesn't have a DC block in it so DC would work.?
Ozan
?
?
On Fri, Sep 6, 2024 at 10:14 AM, Jinxie wrote:
Hi Vladan,
?
Many thanks indeed for your observations. I was certainly aware that the Analyzer would no longer 'know' what level of attenuation was being applied to the source RF and that I would have to manually account for it, but provided that doesn't put any of the downstream circuitry at risk of damage, it's an inconvenience I may have no alternative but to live with.
This SA was owned by an RF engineer and I purchase it from him about 10 years ago along with a faulty Marconi/Aeroflex RF signal generator with a disclosed fault. No faults were disclosed in regards to the SA, however. The sig gen I was able to repair and it's a valuable item of equipment to have for all sorts of reasons. Anyway the fact that the seller disclosed the sig gen fault leads me to believe he was honest and was unaware of any issue with the SA. However, I've never done anything with that SA which could burn out the 0 and 10dB settings either, having used it solely for monitoring the RF environment around me using a short telescopic antenna, so no physical connection to the RF input.
As I mentioned, I do have an HP 8495K 0-70dB attenuator which might save the day. I don't think there are any issues with that. However, it's NOT the same type as the one in the 8566B...
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Jinxie
Dave McGuire
Frank Mashockie
Michael A. Terrell