Re: HP 141T Power Supply Help Needed
"From over 40 years of fault finding and repair experience in a wide range of electronic products, not just instrumentation, the weirdest symptoms often have a really simple root cause!"
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This has been my experience as well! Makes it very easy to go down a rabbit hole. Which is why I always do a thorough visual inspection first. Also checking mechanical components of switches, pots, etc. Giving them a good clean right off the bat and testing those first can save you a lot of headache.
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-Frank
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Re: 8566B Attenuator Service
Hard to be sure from the picture but how do the O-rings look, the
lower one on the far left actuator rod (the 'ribbon cable' end)
looks a bit odd?
Sometimes the O-rings go gooey and sometimes they harden, either way
it can affect the 'throw' of the actuator solenoid - especially the
lower one - which might lead to the symptoms you describe.
On 14/09/2024 17:03, Jinxie via
groups.io wrote:
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Hi all,
?
So I've removed the attenuator and stripped it down to a
point where I can see the important bits and I cannot, from
careful inspection alone, see anything amiss with it (photo
attached). The pads all look nice and there are 4 of them! I'm
guessing one 10dB and the rest 20dB ones. The longer ones
measure about 82 ohms each across their terminals with minor
variations between them and the shorter measures 52 ohms approx.
The springs underneath look like brand new and the plungers do
flip from on to off with just a bit of pressure from a
screwdriver but I haven't tried to actuate them under power
(24V) yet. I thought I'd best pause and get some suggestions
before I do something which could cause damage.
Some of you may recall from a previous thread that when the
attenuator was in circuit and I attempted the calibration
procedure, I saw no signal visible with the 0dB and 10dB
settings. The 20, 30, 40, 50 and 60dB settings seemed okayish
(some a bit noisy) but 70dB was *very* noisy.? Any suggestions
as to how to proceed?
?
Thanks,
?
J.
Attachments:
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Re: 8566B Attenuator Service
That's an old one! The newer versions have a PCB with one-shots on board. These attenuators are pulsed on/off so I'd be warry of using a bench supply to activate the solenoids; you might burn them up and then you're toast!
The better option is to plug it in to the unit and activate that way. You should be able to verify that the spring fingers are moving up and down.
With the pad assemble in place (just a few screws to hold it) you can do a few things. Place an ohmeter between the two ports and verify you have resistance (pretty low) for all combinations. Even better is to used an RF generator and a spectrum analyzer to
measure it. (a scope would also work)
You can try cleaning the springs and pads with IPA but be very careful!
Good luck.
Mark
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Hi all,
?
So I've removed the attenuator and stripped it down to a point where I can see the important bits and I cannot, from careful inspection alone, see anything amiss with it (photo attached). The pads all look nice and there are 4 of them! I'm guessing one
10dB and the rest 20dB ones. The longer ones measure about 82 ohms each across their terminals with minor variations between them and the shorter measures 52 ohms approx. The springs underneath look like brand new and the plungers do flip from on to off with
just a bit of pressure from a screwdriver but I haven't tried to actuate them under power (24V) yet. I thought I'd best pause and get some suggestions before I do something which could cause damage.
Some of you may recall from a previous thread that when the attenuator was in circuit and I attempted the calibration procedure, I saw no signal visible with the 0dB and 10dB settings. The 20, 30, 40, 50 and 60dB settings seemed okayish (some a bit noisy)
but 70dB was *very* noisy.? Any suggestions as to how to proceed?
?
Thanks,
?
J.
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Re: 8566B Attenuator Service
Hello Jinxie,
It seems you have indeed one 10dB, one 20 dB and two 20dB combined to make 40.
From what you say I'd think the 10dB is the culprit. 60 ok, 70 not?
Remember for the test what someone above suggested: Why not try it with low voltage CC? Very easy to measure the attenuation and to see on a scope if it's noisy!
Not much, just my 2€cents!
Best,
Renaud
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Re: HP 141T Power Supply Help Needed
Different load is very plausible, but if so, I'm disappointed they didn't annotate it.? Tsk.
Dave Wise
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Re:-
"That discrepancy between A2Q9.C and Q4.C is certainly a typo, or
perhaps the two points were measured at different times and the mains
voltage changed, and no-one noticed that they're by definition the same."
Under different load conditions perhaps?? (Plug-ins present, or not.)
I see there is also mention of 2V ripple on the +ve unregulated side
(Q4.Q9 collector.)? Presumably when under some unspecified load.
(I don't have a copy of the full manual.)
Regards.
Dave B.
--
Created on and sent from a Unix like PC running and using open source software:
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Hi all,
?
So I've removed the attenuator and stripped it down to a point where I can see the important bits and I cannot, from careful inspection alone, see anything amiss with it (photo attached). The pads all look nice and there are 4 of them! I'm guessing one 10dB and the rest 20dB ones. The longer ones measure about 82 ohms each across their terminals with minor variations between them and the shorter measures 52 ohms approx. The springs underneath look like brand new and the plungers do flip from on to off with just a bit of pressure from a screwdriver but I haven't tried to actuate them under power (24V) yet. I thought I'd best pause and get some suggestions before I do something which could cause damage.
Some of you may recall from a previous thread that when the attenuator was in circuit and I attempted the calibration procedure, I saw no signal visible with the 0dB and 10dB settings. The 20, 30, 40, 50 and 60dB settings seemed okayish (some a bit noisy) but 70dB was *very* noisy.? Any suggestions as to how to proceed?
?
Thanks,
?
J.
|
Re: N9010A 32-bit XSA Software for Windows 7
Thanks Stan,
?
The unit can run the 32-bit version of Windows 7 - You can also get the custom devices to install by extracting the Windows XP drivers and then dropping the correct WDFCoInstaller DLL into the same directory (Don't know if they work as we didn't have the XSA App Running).
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So it appears to be all ready except for the XSA app. I've heard that there were license key issues but, again, without a 32-bit version of the app I couldn't tell.
?
I'm not after any specific version of the XSA app so any one that you can find that is Windows 7 only would work - I do know that A.24.56 is a 64-bit version of the app so it should be earlier than that
?
Thanks,
?
TonyG
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Re: HP 141T Power Supply Help Needed
F4 had blown when I was getting 24v.??? I replaced it and q4, soldering both pins of q4 temporarily.?? It's possible the "one good" inseption clip was not.???
I'm just glad to be over that for now...
Hi again.
?From the above measurements, it looks like Q4 is bad (open collector?)?
But later it is said the -12.6 rail came good.
Intermittent connections around Q4, as someone (forget who) mentioned
happened due to a bad power transistor heatsink mounted socket, that I
too in the past have had troubles with, in other makers kit where they
were used for convenience.? Or other bad connection issue(s).
It would be worth checking F4 and it's holder or clips if PCB mounted,
and their soldering on the PCB too perhaps.
The + and - 100V rails don't seem too far out, for now.
The -24V episode on the -12V rail, might have damaged (for example)
flood gun filaments in the CRT (if your instrument has a storage tube.)?
There was I recall, one other who said they had a tube with burnt out
flood gun filaments.?? Or was that with F4 removed, and you saw that on
the transformer side of F4?
?From over 40 years of fault finding and repair experience in a wide
range of electronic products, not just instrumentation, the weirdest
symptoms often have a really simple root cause!
Regards to All.
Dave B.
--
Created on and sent from a Unix like PC running and using open source software:
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FREE: HP manual binders (and some manuals)
I have a quantity of not very useful HP test equipment manuals in small 3-ring binders.? I'm planning to recycle them, but I wondered if anyone could use the binders.? The page size is 7" x 8.5" and most of them have 2" rings/3" spine.? They are free, but you pay postage by PayPal/Venmo/etc.? I am located in Montana, USA, 59715
If interested, send me a private message with the quantity wanted, complete shipping address, email address, and preferred shipping method if any.? Do not post to the list, thanks.
Of course if you actually want the manuals, you can have them as well (it may take longer to find the ones you want).? Here is a partial list:
HP 8360 User's Handbook 08360-90070
HP 8360B/L troubleshooting 08360-90124
HP 8360L User's Guide 08360-90134
HP 8560E calibration 08560-90093
HP 8560E User's Guide 5961-0490, 8560-90110
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Re: HP 141T Power Supply Help Needed
Hi again.
From the above measurements, it looks like Q4 is bad (open collector?)? But later it is said the -12.6 rail came good.
Intermittent connections around Q4, as someone (forget who) mentioned happened due to a bad power transistor heatsink mounted socket, that I too in the past have had troubles with, in other makers kit where they were used for convenience.? Or other bad connection issue(s).
It would be worth checking F4 and it's holder or clips if PCB mounted, and their soldering on the PCB too perhaps.
The + and - 100V rails don't seem too far out, for now.
The -24V episode on the -12V rail, might have damaged (for example) flood gun filaments in the CRT (if your instrument has a storage tube.)? There was I recall, one other who said they had a tube with burnt out flood gun filaments.?? Or was that with F4 removed, and you saw that on the transformer side of F4?
From over 40 years of fault finding and repair experience in a wide range of electronic products, not just instrumentation, the weirdest symptoms often have a really simple root cause!
Regards to All.
Dave B.
--
Created on and sent from a Unix like PC running and using open source software:
|
Re: HP 141T Power Supply Help Needed
While I wait for a new socket, I went ahead and soldered the transistor in the relevant socket.? ? The other sockets look ok.? ?
Like I say, I now have all 4 supplies running and adjusted.? ? ?Starting to muse over the A5 board presently.? ?I guess flood gun damage is possible,?
but I'll check out the pulse and blank portions first.? ? ?Will report back as that progresses.? ?
On Sat, Sep 14, 2024 at 11:16?AM Michael Bafaro via <m.bafaro= [email protected]> wrote: Bill, ? My friend Pete brought over his 141T with plugins and it was intermittent and I found that the pass devices were not always making contact.? The sockets have been thermal cycled enough that the brass contacts have been annealed.? I had it all working and all of a sudden the -100 was missing.? I tapped the pass device and it started working again!? I removed the collector screws and if it were not for the sill pad the transistor would have fallen out!!? It had ZERO insertion force.? I ordered some new sockets Keystone Electronics P/N? 4608 and installed them and now it is solid.? The sockets are riveted in and that was a real pain as well as having to unsolder all of the wires and working in that small space to get the screws out and back in.? UGH. I installed the new sockets with 4-40 X ? screws lock washers and nuts and incase the phenolic shrinks with age I put some Locktite on the threads. ? Mike ? ? All 4 voltages look good now.?? I popped the plugins into the case.?? 3 lights - scanning, log ref 0 and an X.??? No life on the crt however.?? Going to take a break and Crack open the manual some more.????? Not super pumped that it just started working, especially without a root cause.? But I'll take it for today man... ? On Sat, Sep 14, 2024, 10:23?AM Bill Berzinskas via <bberzinskas=[email protected]> wrote: Try this again....?? I've been marking this schematic for to long to keep it straight... I am looking at it though Q9
E 1.5
B 2.2
C 17 Q10
E 0
B .6
C 2.2 Q11
E 1.66
B -2.3
C 2.2 Across cr1 and cr2 is 23v.? I measure 98.7 and -99v on other supplies currently.? Now this is absolutely wild....? doing nothing other than measuring around, I now have a very adjustable negative supply.???? Started on -15 and adjusted to -12.6 with no problem.??? Uggh.? I don't understand what just happened.?? ? On Sat, Sep 14, 2024, 9:50?AM Frank Mashockie via <fmashockie=[email protected]> wrote: Also, as a sanity check, when is the last time you checked the other rails?? Is your -100V rail still in spec?? Without a temp compensated zener, these 140/180 power supplies can get unstable.? I've seen them intermittently drop all the rails due to similar issues.
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Re: HP 141T Power Supply Help Needed
Bill, ? My friend Pete brought over his 141T with plugins and it was intermittent and I found that the pass devices were not always making contact.? The sockets have been thermal cycled enough that the brass contacts have been annealed.? I had it all working and all of a sudden the -100 was missing.? I tapped the pass device and it started working again!? I removed the collector screws and if it were not for the sill pad the transistor would have fallen out!!? It had ZERO insertion force.? I ordered some new sockets Keystone Electronics P/N? 4608 and installed them and now it is solid.? The sockets are riveted in and that was a real pain as well as having to unsolder all of the wires and working in that small space to get the screws out and back in.? UGH. I installed the new sockets with 4-40 X ? screws lock washers and nuts and incase the phenolic shrinks with age I put some Locktite on the threads. ? Mike ?
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From: [email protected] < [email protected]> On Behalf Of Bill Berzinskas Sent: Saturday, September 14, 2024 9:37 AM To: [email protected]Subject: Re: [HP-Agilent-Keysight-equipment] HP 141T Power Supply Help Needed ? All 4 voltages look good now.?? I popped the plugins into the case.?? 3 lights - scanning, log ref 0 and an X.??? No life on the crt however.?? Going to take a break and Crack open the manual some more.????? Not super pumped that it just started working, especially without a root cause.? But I'll take it for today man... ? On Sat, Sep 14, 2024, 10:23?AM Bill Berzinskas via <bberzinskas=[email protected]> wrote: Try this again....?? I've been marking this schematic for to long to keep it straight... I am looking at it though Q9
E 1.5
B 2.2
C 17 Q10
E 0
B .6
C 2.2 Q11
E 1.66
B -2.3
C 2.2 Across cr1 and cr2 is 23v.? I measure 98.7 and -99v on other supplies currently.? Now this is absolutely wild....? doing nothing other than measuring around, I now have a very adjustable negative supply.???? Started on -15 and adjusted to -12.6 with no problem.??? Uggh.? I don't understand what just happened.?? ? On Sat, Sep 14, 2024, 9:50?AM Frank Mashockie via <fmashockie=[email protected]> wrote: Also, as a sanity check, when is the last time you checked the other rails?? Is your -100V rail still in spec?? Without a temp compensated zener, these 140/180 power supplies can get unstable.? I've seen them intermittently drop all the rails due to similar issues.
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Re: HP 141T Power Supply Help Needed
Thats awesome Bill!? I would not have expected those rectifier diodes either.? They are tough little guys.??
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-Frank
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Re: HP 141T Power Supply Help Needed
Bill, ? Wow!? Bad diodes I would not have expected that.? Now you have to check the pass device and the rest? of the regulator. ? Mike ?
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From: [email protected] < [email protected]> On Behalf Of Bill Berzinskas Sent: Saturday, September 14, 2024 12:19 AM To: [email protected]Subject: Re: [HP-Agilent-Keysight-equipment] HP 141T Power Supply Help Needed ? For S&Gs, I jumpered in a set of SB520 and that brought the -12.6v output up to ~23v!? ? I went ahead and ordered 1N3209s.?
-23v is a bit concerning, but I will check the pass trans one more time and remeasure everything in the morning.? ? ? On Sat, Sep 14, 2024 at 12:38?AM Bill Berzinskas via <bberzinskas=[email protected]> wrote: Took both side panels off, dug the transistor holder out a bit more and proceeded to trace the wiring.? ?It all checks out, but I now have strong reservations about the status of CR1 and CR2.? ?I believe I am seeing?
Anode - 24v dc / 17v ac
Cathode - 0.5v DC
Assuming it should register something on my DMM, since its a diode and all..? ?Nothing.? ??
I take it these are the source of all my woes?? ? Not sure what the heck I was measuring before..??
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Re: HP 141T Power Supply Help Needed
Bill, ? See that there is continuity from the ?negative side of C6 to the anodes of the diodes.?? If that is good use the diode scale on the DMM and see that? you have about .7V forward on each diode. ?You may have to disconnect the common cathode connection which is on the outside of the unit. ?These are stud mounted diodes and should be almost indestructible. ? Mike ?
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From: [email protected] < [email protected]> On Behalf Of Bill Berzinskas Sent: Friday, September 13, 2024 11:39 PM To: [email protected]Subject: Re: [HP-Agilent-Keysight-equipment] HP 141T Power Supply Help Needed ? Took both side panels off, dug the transistor holder out a bit more and proceeded to trace the wiring.? ?It all checks out, but I now have strong reservations about the status of CR1 and CR2.? ?I believe I am seeing?
Anode - 24v dc / 17v ac
Cathode - 0.5v DC
Assuming it should register something on my DMM, since its a diode and all..? ?Nothing.? ??
I take it these are the source of all my woes?? ? Not sure what the heck I was measuring before..??
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Re: HP 141T Power Supply Help Needed
All 4 voltages look good now.?? I popped the plugins into the case.?? 3 lights - scanning, log ref 0 and an X.??? No life on the crt however.??
Going to take a break and Crack open the manual some more.????? Not super pumped that it just started working, especially without a root cause.? But I'll take it for today man...
On Sat, Sep 14, 2024, 10:23?AM Bill Berzinskas via <bberzinskas= [email protected]> wrote: Try this again....?? I've been marking this schematic for to long to keep it straight... I am looking at it though
Q9
E 1.5
B 2.2
C 17
Q10
E 0
B .6
C 2.2
Q11
E 1.66
B -2.3
C 2.2
Across cr1 and cr2 is 23v.?
I measure 98.7 and -99v on other supplies currently.?
Now this is absolutely wild....? doing nothing other than measuring around, I now have a very adjustable negative supply.???? Started on -15 and adjusted to -12.6 with no problem.??? Uggh.? I don't understand what just happened.??
On Sat, Sep 14, 2024, 9:50?AM Frank Mashockie via <fmashockie= [email protected]> wrote: Also, as a sanity check, when is the last time you checked the other rails?? Is your -100V rail still in spec?? Without a temp compensated zener, these 140/180 power supplies can get unstable.? I've seen them intermittently drop all the rails due to similar issues.
?
-Frank
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Re: HP 141T Power Supply Help Needed
Try this again....?? I've been marking this schematic for to long to keep it straight... I am looking at it though
Q9
E 1.5
B 2.2
C 17
Q10
E 0
B .6
C 2.2
Q11
E 1.66
B -2.3
C 2.2
Across cr1 and cr2 is 23v.?
I measure 98.7 and -99v on other supplies currently.?
Now this is absolutely wild....? doing nothing other than measuring around, I now have a very adjustable negative supply.???? Started on -15 and adjusted to -12.6 with no problem.??? Uggh.? I don't understand what just happened.??
On Sat, Sep 14, 2024, 9:50?AM Frank Mashockie via <fmashockie= [email protected]> wrote: Also, as a sanity check, when is the last time you checked the other rails?? Is your -100V rail still in spec?? Without a temp compensated zener, these 140/180 power supplies can get unstable.? I've seen them intermittently drop all the rails due to similar issues.
?
-Frank
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Re: N9010A 32-bit XSA Software for Windows 7
Hi Tony,
?
It's been quite a while since I did this, so I don't recall if the upgrade to Win7 required a 64-bit capable CPU, but ISTR that it did. I do remember having to buy a new processor board for my N9020A for the OS upgrade.
?
If I am wrong about the 64-bit requirement, I have several older Win7 versions of the XSA software and I'd be happy to Dropbox one of them to you. What version were you running under XP?
?
BTW, I looked through several different release notes, but in none of them could I find any indications that the Win7 OS was required to be 64-bit. That may just have been assumed. I think the determination of compatibility of the OS and the XSA software was left up to the installer software.
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Regards,
Stan
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Re: HP 141T Power Supply Help Needed
Also, as a sanity check, when is the last time you checked the other rails?? Is your -100V rail still in spec?? Without a temp compensated zener, these 140/180 power supplies can get unstable.? I've seen them intermittently drop all the rails due to similar issues.
?
-Frank
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Re: HP 141T Power Supply Help Needed
Bill,
?
Your measurements aren't making sense.? Also, this is being compounded by not providing enough info as to what point you are referencing when you take your measurements.? For example, Mike asked for voltage measurements across anodes and cathodes of CR1 and CR2.??
?
Not sure how you have 1.5V at the emitter and 1.3V at base of Q9.? There should be 0.6V drop from base to emitter there.? Unless you've transcribed your measurements wrong, popped in a transistor backwards, etc.? Also, you state you have 2.2V at Cs of Q10 and Q11.? Well those are tied to the base of Q9 - which you reported as = 1.3V.? They should all be at the same potential.
?
Are you referencing the schematic?? The service manual is widely available online.? I think if you were, you'd be seeing some of these discrepencies.??
?
-Frank
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Frank Mashockie
Jinxie
