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Re: HP 8566B repair: -10V rail went down

 

"Radu Bogdan Dicher" <vondicher@...> writes:

That said, I find an intermittent header contact - or any other contacts -
much more likely a source of intermittent behaviors of the circuit. I'd
typically clean up such things with 99.99% pure IPA, and then apply a
conservative amount of deoxit for contact conditioning (most contacts
benefit from this). But be careful near plastic, as it can affect it
negatively in time.
Radu.
That's what I'm thinking too. It seems possible it's a failing cap, but
it's going to be really hard to track down unless it gives me a
consistent error to diagnose, especially since the -10V rail feeds so
much downstream circuitry, and a lot of it like the YTO loop and RF
module are hard to get at.

It also seems really possible (and maybe more likely, as you mention)
that some board wasn't properly seated, or a connector was loose, or
similar, especially since it demonstrated the error after spending some
time in the trunk of a car. I did pull out and reseat a number of cards
while troubleshooting, so it's possible I inadvertently fixed the
problem. Still, I don't totally understand why this would cause the -10V
rail to disappear.

If there was a failing cap on the -10V rail I think I'd see some
ripple. But I didn't measure any.

Since I'm not inclined to pull apart the entire instrument looking for a
problem that will be hard to recognize when I see it, I think I'll
probably put the instrument back and wait for the problem to reappear to
troubleshoot. If anyone thinks this is a bad idea, please let me know.

FWIW, my supply is current-limited but I set the limit to the current
rating of the -10V fuse (i.e., 5A). I did quadruple check that I got
polarity right, so I don't think that was the problem (and my supply is
floating). I probably should have set the limit lower, but I had trouble
finding how much current that regulator should supply under normal
conditions. I'm now measuring a current draw of about 1.5A.

Matt
Re: HP 8566B repair: -10V rail went down

 

That said, I find an intermittent?header contact - or any other contacts - much more likely a source of intermittent behaviors of the circuit. I'd typically clean up such things with 99.99% pure IPA, and then apply a conservative amount of deoxit for contact conditioning (most contacts benefit from this). But be careful near plastic, as it can affect it negatively in time.
Radu.?

Virus-free.


On Mon, Jan 17, 2022 at 2:40 PM Radu Dicher <vondicher@...> wrote:
Matt,
I think I've seen intermittent failures with "not quite shorted" tantalum caps (maybe driven by heat?). Generally speaking, tantalums seem to either fail spectacularly - lots of smoke, sparkles, and smell - or very inconspicuously, such as this cap I recently honed into, that was bringing the entire switching supply?of a Tektornix scope I was working on into "ticking mode," and all that was visible was a tiny silver bob on its side. I saw it with a large self-lighted magnifier, as it was not visible to the naked eye. At least not mine.?

But if you got smoke during the "un-overcurrent-protected" -10V external?supplying (are you sure it was 10V lower than whatever ground you supplied it with into the circuit, externally?) I suggest a good look at the source of the smoke and see the effect on the stressed component. Hopefully, it's a solid ground from PCB to a stanoff, or something similar that may be able to take it, but it may be a component that may now fail shortly, and the bonus is it may give you information on the underlying problem.?

My bench power supply - as most of them are - is both voltage and current adjustable, so it'd never exceed a certain current into a faulty circuit.?

Good luck!
Radu.?

Virus-free.

On Mon, Jan 17, 2022 at 2:10 PM Siggi via <siggi=[email protected]> wrote:
Hey Matt,

Here's a problem I found in my IF unit:?/g/HP-Agilent-Keysight-equipment/message/89319. Apparently this is somewhat endemic there, though I only have a sample of one. I've never been into my RF unit in anger, but maybe the connector from the transformer is worth looking at critically?

Siggi

On Mon, Jan 17, 2022 at 4:23 PM Matt Huszagh <huszaghmatt@...> wrote:
"Bruce" <bruce@...> writes:

> I agree that providing an uncurrent limited -10v was a mistake.
>
> Some suggestions:
> 1) A loose part (screw, nut, washer) that found itself a place
> shorting the -10v seems likely
> 2) A cap failure - how long was the 8566 off - long enough for the cap
> to depolarize.

I hadn't considered that first possibility. Thanks for the hint! I did
at some point measure a short across the -10V rail, but I wasn't able to
reproduce the measurement. Maybe that could be a screw sometimes
shorting the rail. Will keep an eye out.

Do failing caps ever intermittently present shorts? I've read that most
8566 failures are from electrolytics, so I'm on the lookout for
that. But I'm a bit surprised that this rail is sometimes up and
sometimes not.

> Thoughts on how to proceed:
> Isolate sections of the power distribution on the PCB -pull cards,
> pull connectors, etc.
> If something smoked, it will be either a component on a PCB or the
> motherboard (There are a few).? Or it could be a PCB trace (bad news
> if it is in a relatively inaccessible place.
>
> Hardest but most through is to remove all cards, test for appropriate
> voltages and then plug in a selection of cards.? I usually start with
> the control section (CPU, etc), then RF, then M/N, then 20/30.? Don't
> forget the front pannel, but it is easy to isolate (don't remember if
> -10v is used on FP - think it is not).

For anyone else that sees this, the A8 rectifier assembly provides a
nice list of the assemblies fed by the various power rails. For the -10V
rail, I believe all the downstream modules are:

- A19 DAC
- A20 main coil driver
- A21 FM coil driver
- A11A4 YTO phase detector
? - C3
- A11A5 sampler
? - C3
- A6 RF module
- A7A5 reference
- A16 scan generator
- A10A5 PLL2 VCO
- A10A1 PLL1 VCO
- A10A6 PLL2 phase detector
- A10A3 PLL1 IF
- A10A7 PLL2 divider
- A10A4 PLL3 up converter
- A10A8 PLL2 discriminator

and for the -5.2V rail:

- A17 positive regulator
- A11 YTO loop
- A7A5 reference
- A15 controller
- A16 scan generator

Matt
Re: HP 8566B repair: -10V rail went down

 

Matt,
I think I've seen intermittent failures with "not quite shorted" tantalum caps (maybe driven by heat?). Generally speaking, tantalums seem to either fail spectacularly - lots of smoke, sparkles, and smell - or very inconspicuously, such as this cap I recently honed into, that was bringing the entire switching supply?of a Tektornix scope I was working on into "ticking mode," and all that was visible was a tiny silver bob on its side. I saw it with a large self-lighted magnifier, as it was not visible to the naked eye. At least not mine.?

But if you got smoke during the "un-overcurrent-protected" -10V external?supplying (are you sure it was 10V lower than whatever ground you supplied it with into the circuit, externally?) I suggest a good look at the source of the smoke and see the effect on the stressed component. Hopefully, it's a solid ground from PCB to a stanoff, or something similar that may be able to take it, but it may be a component that may now fail shortly, and the bonus is it may give you information on the underlying problem.?

My bench power supply - as most of them are - is both voltage and current adjustable, so it'd never exceed a certain current into a faulty circuit.?

Good luck!
Radu.?

Virus-free.


On Mon, Jan 17, 2022 at 2:10 PM Siggi via <siggi=[email protected]> wrote:
Hey Matt,

Here's a problem I found in my IF unit:?/g/HP-Agilent-Keysight-equipment/message/89319. Apparently this is somewhat endemic there, though I only have a sample of one. I've never been into my RF unit in anger, but maybe the connector from the transformer is worth looking at critically?

Siggi

On Mon, Jan 17, 2022 at 4:23 PM Matt Huszagh <huszaghmatt@...> wrote:
"Bruce" <bruce@...> writes:

> I agree that providing an uncurrent limited -10v was a mistake.
>
> Some suggestions:
> 1) A loose part (screw, nut, washer) that found itself a place
> shorting the -10v seems likely
> 2) A cap failure - how long was the 8566 off - long enough for the cap
> to depolarize.

I hadn't considered that first possibility. Thanks for the hint! I did
at some point measure a short across the -10V rail, but I wasn't able to
reproduce the measurement. Maybe that could be a screw sometimes
shorting the rail. Will keep an eye out.

Do failing caps ever intermittently present shorts? I've read that most
8566 failures are from electrolytics, so I'm on the lookout for
that. But I'm a bit surprised that this rail is sometimes up and
sometimes not.

> Thoughts on how to proceed:
> Isolate sections of the power distribution on the PCB -pull cards,
> pull connectors, etc.
> If something smoked, it will be either a component on a PCB or the
> motherboard (There are a few).? Or it could be a PCB trace (bad news
> if it is in a relatively inaccessible place.
>
> Hardest but most through is to remove all cards, test for appropriate
> voltages and then plug in a selection of cards.? I usually start with
> the control section (CPU, etc), then RF, then M/N, then 20/30.? Don't
> forget the front pannel, but it is easy to isolate (don't remember if
> -10v is used on FP - think it is not).

For anyone else that sees this, the A8 rectifier assembly provides a
nice list of the assemblies fed by the various power rails. For the -10V
rail, I believe all the downstream modules are:

- A19 DAC
- A20 main coil driver
- A21 FM coil driver
- A11A4 YTO phase detector
? - C3
- A11A5 sampler
? - C3
- A6 RF module
- A7A5 reference
- A16 scan generator
- A10A5 PLL2 VCO
- A10A1 PLL1 VCO
- A10A6 PLL2 phase detector
- A10A3 PLL1 IF
- A10A7 PLL2 divider
- A10A4 PLL3 up converter
- A10A8 PLL2 discriminator

and for the -5.2V rail:

- A17 positive regulator
- A11 YTO loop
- A7A5 reference
- A15 controller
- A16 scan generator

Matt
Re: HP 8566B repair: -10V rail went down

 

"Siggi via groups.io" <siggi@...> writes:

Here's a problem I found in my IF unit:
/g/HP-Agilent-Keysight-equipment/message/89319. Apparently
this is somewhat endemic there, though I only have a sample of one. I've
never been into my RF unit in anger, but maybe the connector from the
transformer is worth looking at critically?
Interesting, thanks for the heads up Siggi. The unregulated ~18V input
to the negative regulator always appeared consistent to me, and the -40V
from that same assembly was never intermittent. But, I'll keep an eye on
that.

Matt
Re: HP 8566B repair: -10V rail went down

 

Hey Matt,

Here's a problem I found in my IF unit:?/g/HP-Agilent-Keysight-equipment/message/89319. Apparently this is somewhat endemic there, though I only have a sample of one. I've never been into my RF unit in anger, but maybe the connector from the transformer is worth looking at critically?

Siggi

On Mon, Jan 17, 2022 at 4:23 PM Matt Huszagh <huszaghmatt@...> wrote:
"Bruce" <bruce@...> writes:

> I agree that providing an uncurrent limited -10v was a mistake.
>
> Some suggestions:
> 1) A loose part (screw, nut, washer) that found itself a place
> shorting the -10v seems likely
> 2) A cap failure - how long was the 8566 off - long enough for the cap
> to depolarize.

I hadn't considered that first possibility. Thanks for the hint! I did
at some point measure a short across the -10V rail, but I wasn't able to
reproduce the measurement. Maybe that could be a screw sometimes
shorting the rail. Will keep an eye out.

Do failing caps ever intermittently present shorts? I've read that most
8566 failures are from electrolytics, so I'm on the lookout for
that. But I'm a bit surprised that this rail is sometimes up and
sometimes not.

> Thoughts on how to proceed:
> Isolate sections of the power distribution on the PCB -pull cards,
> pull connectors, etc.
> If something smoked, it will be either a component on a PCB or the
> motherboard (There are a few).? Or it could be a PCB trace (bad news
> if it is in a relatively inaccessible place.
>
> Hardest but most through is to remove all cards, test for appropriate
> voltages and then plug in a selection of cards.? I usually start with
> the control section (CPU, etc), then RF, then M/N, then 20/30.? Don't
> forget the front pannel, but it is easy to isolate (don't remember if
> -10v is used on FP - think it is not).

For anyone else that sees this, the A8 rectifier assembly provides a
nice list of the assemblies fed by the various power rails. For the -10V
rail, I believe all the downstream modules are:

- A19 DAC
- A20 main coil driver
- A21 FM coil driver
- A11A4 YTO phase detector
? - C3
- A11A5 sampler
? - C3
- A6 RF module
- A7A5 reference
- A16 scan generator
- A10A5 PLL2 VCO
- A10A1 PLL1 VCO
- A10A6 PLL2 phase detector
- A10A3 PLL1 IF
- A10A7 PLL2 divider
- A10A4 PLL3 up converter
- A10A8 PLL2 discriminator

and for the -5.2V rail:

- A17 positive regulator
- A11 YTO loop
- A7A5 reference
- A15 controller
- A16 scan generator

Matt
Re: HP 8566B repair: -10V rail went down

 

¿ªÔÆÌåÓý

Matt, FWIW my Wavetek 166 function generator had a flaky -5.2 V rail that dropped out after about 5 minutes after power up.? I assumed it was a cap and replaced several.? Didn't help. And after poking around a bit, I found the -5.2 V was fine on the power supply board but dropped out on the destination board.? Turns out it was a poor contact on the power supply connector.? I bent the male pin just a tad so it made better contact, and the problem has never returned.? Could be something similar in your 8566 (also got one of those myself).? HTH.? ? ? ? Jim Ford?



Sent from my T-Mobile 4G LTE Device


-------- Original message --------
From: Matt Huszagh <huszaghmatt@...>
Date: 1/17/22 1:23 PM (GMT-08:00)
To: Bruce <bruce@...>, [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP 8566B repair: -10V rail went down

"Bruce" <bruce@...> writes:

> I agree that providing an uncurrent limited -10v was a mistake.
>
> Some suggestions:
> 1) A loose part (screw, nut, washer) that found itself a place
> shorting the -10v seems likely
> 2) A cap failure - how long was the 8566 off - long enough for the cap
> to depolarize.

I hadn't considered that first possibility. Thanks for the hint! I did
at some point measure a short across the -10V rail, but I wasn't able to
reproduce the measurement. Maybe that could be a screw sometimes
shorting the rail. Will keep an eye out.

Do failing caps ever intermittently present shorts? I've read that most
8566 failures are from electrolytics, so I'm on the lookout for
that. But I'm a bit surprised that this rail is sometimes up and
sometimes not.

> Thoughts on how to proceed:
> Isolate sections of the power distribution on the PCB -pull cards,
> pull connectors, etc.
> If something smoked, it will be either a component on a PCB or the
> motherboard (There are a few).? Or it could be a PCB trace (bad news
> if it is in a relatively inaccessible place.
>
> Hardest but most through is to remove all cards, test for appropriate
> voltages and then plug in a selection of cards.? I usually start with
> the control section (CPU, etc), then RF, then M/N, then 20/30.? Don't
> forget the front pannel, but it is easy to isolate (don't remember if
> -10v is used on FP - think it is not).

For anyone else that sees this, the A8 rectifier assembly provides a
nice list of the assemblies fed by the various power rails. For the -10V
rail, I believe all the downstream modules are:

- A19 DAC
- A20 main coil driver
- A21 FM coil driver
- A11A4 YTO phase detector
? - C3
- A11A5 sampler
? - C3
- A6 RF module
- A7A5 reference
- A16 scan generator
- A10A5 PLL2 VCO
- A10A1 PLL1 VCO
- A10A6 PLL2 phase detector
- A10A3 PLL1 IF
- A10A7 PLL2 divider
- A10A4 PLL3 up converter
- A10A8 PLL2 discriminator

and for the -5.2V rail:

- A17 positive regulator
- A11 YTO loop
- A7A5 reference
- A15 controller
- A16 scan generator

Matt
Re: HP 8566B repair: -10V rail went down

 

"Bruce" <bruce@...> writes:

I agree that providing an uncurrent limited -10v was a mistake.

Some suggestions:
1) A loose part (screw, nut, washer) that found itself a place
shorting the -10v seems likely
2) A cap failure - how long was the 8566 off - long enough for the cap
to depolarize.
I hadn't considered that first possibility. Thanks for the hint! I did
at some point measure a short across the -10V rail, but I wasn't able to
reproduce the measurement. Maybe that could be a screw sometimes
shorting the rail. Will keep an eye out.

Do failing caps ever intermittently present shorts? I've read that most
8566 failures are from electrolytics, so I'm on the lookout for
that. But I'm a bit surprised that this rail is sometimes up and
sometimes not.

Thoughts on how to proceed:
Isolate sections of the power distribution on the PCB -pull cards,
pull connectors, etc.
If something smoked, it will be either a component on a PCB or the
motherboard (There are a few). Or it could be a PCB trace (bad news
if it is in a relatively inaccessible place.

Hardest but most through is to remove all cards, test for appropriate
voltages and then plug in a selection of cards. I usually start with
the control section (CPU, etc), then RF, then M/N, then 20/30. Don't
forget the front pannel, but it is easy to isolate (don't remember if
-10v is used on FP - think it is not).
For anyone else that sees this, the A8 rectifier assembly provides a
nice list of the assemblies fed by the various power rails. For the -10V
rail, I believe all the downstream modules are:

- A19 DAC
- A20 main coil driver
- A21 FM coil driver
- A11A4 YTO phase detector
- C3
- A11A5 sampler
- C3
- A6 RF module
- A7A5 reference
- A16 scan generator
- A10A5 PLL2 VCO
- A10A1 PLL1 VCO
- A10A6 PLL2 phase detector
- A10A3 PLL1 IF
- A10A7 PLL2 divider
- A10A4 PLL3 up converter
- A10A8 PLL2 discriminator

and for the -5.2V rail:

- A17 positive regulator
- A11 YTO loop
- A7A5 reference
- A15 controller
- A16 scan generator

Matt
New to the group, troubleshooting HP4261A

GeoVE3GZB
 

Hi from Canada?

I have a recently acquired LCR meter, the relatively compact 4261A.

It seems to have a very quirky problem. When left overnight powered off then powered up next day it runs normally for a while. Then the display starts flickering with all manner of random digits, the sound of relays clicking is heard.

Thinking it was simply due for a recap (and one of the PSU caps did show a bulge) I ordered replacement caps from Digi-Key and replaced all electrolytic caps.

The problem seemed to go away for a short time only to return.

+12, -12 and +5 Volt rails show correct DC levels with no ripple.

I¡¯ve tried to chill this device by leaving it outside for a little while to see if temperature is a trigger. It is not.

Help?
geo
Re: HP 8566B repair: -10V rail went down

 

Update:

I plugged in the instrument and left it long enough for the oven to warm
up. I then powered it on. No error messages appeared and the instrument
sweeps fine. I provided a few test signals to the input and they all
look good. 5 GHz, 10 GHz and 15 GHz at 0 dBm all appear as they should.

There's obviously still a problem, but it no longer sounds like my
blunder caused serious damage. I'll keep searching downstream of the -10
and -5.2V rails.

Matt
Re: HP 8566B repair: -10V rail went down

 

I agree that providing an uncurrent limited -10v was a mistake.

Some suggestions:
1) A loose part (screw, nut, washer) that found itself a place shorting the -10v seems likely
2) A cap failure - how long was the 8566 off - long enough for the cap to depolarize.

Thoughts on how to proceed:
Isolate sections of the power distribution on the PCB -pull cards, pull connectors, etc.
If something smoked, it will be either a component on a PCB or the motherboard (There are a few). Or it could be a PCB trace (bad news if it is in a relatively inaccessible place.

Hardest but most through is to remove all cards, test for appropriate voltages and then plug in a selection of cards. I usually start with the control section (CPU, etc), then RF, then M/N, then 20/30. Don't forget the front pannel, but it is easy to isolate (don't remember if -10v is used on FP - think it is not).

Fun times are afoot :-)

Cheers!

Bruce



Quoting Matt Huszagh <huszaghmatt@...>:

Hello,

I've got an HP 8566B that was functioning correctly. However, after
moving to a new apartment, it stopped working.

The first thing I did was to check the power rails. Sure enough, the
-10V rail showed 0V across it. I probed different points on the negative
regulator. This seemed to be functioning correctly: the opamp had a
diode forward voltage drop across it's inputs and was driving the output
to about 17V. The voltages at A23Q1 (the darlington that provides
current for this rail) were C=17V, B=1.6V and E=250mV. However, the
voltage across the current sensing resistors was only about 250mV (so
the current through them was about 600mA). I believed this meant A23Q1
wasn't able to source enough current and was therefore the faulty
component.

My next move, in retrospect, I believe was stupid. Thinking this
transistor was at fault, I attempted to supply the -10V externally. The
unit began to smoke and smell burnt and I pulled the power.

Now if I turn on the unit, the -10V rail sometimes comes on and other
times does not. Unfortunately this makes it a bit tricky to diagnose
since I can't just pull assemblies until the supply comes back up.

Thoughts on how to proceed? I'm concerned I did some serious damage
supplying external power.

Thanks
Matt
Re: HP Diode ID Help

 

¿ªÔÆÌåÓý

Thank you, Greg. I transposed the 3 and 8, so I gave info for -2803 diodes. Similar enough for most cases, probably, but ain't the same. Greatly appreciate the correction!

As to the mismatch criteria, do you happen to have those values? You list the test conditions (thanks!), but not the allowed limits.

--Cheers,
Tom
-- 
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
On 1/17/2022 10:08, Greg Muir via groups.io wrote:

Just some additional information

The individual diodes for this pair are found under part number 5082-2303.
HP crosses that diode directly to a 1N5167.

?

5082-2303 diode specifications:

??????????? Minimum breakdown voltage VBR (V): 20

??????????? Minimum forward voltage VF (mV): 400

??????????? VF = 1V Max at forward current IF (mA): 35

??????????? Maximum reverse leakage current : IR (nA): 500 at VR (V): 15

??????????? Maximum capacitance CT (pF): 1.0

??????????? ???????????

5082-2308 diode pair matching test conditions:

¦¤³Õf at If = 0.75V at 20 mA

¦¤°äo at f = 1.0 MHz

Greg
HP 8566B repair: -10V rail went down

 

Hello,

I've got an HP 8566B that was functioning correctly. However, after
moving to a new apartment, it stopped working.

The first thing I did was to check the power rails. Sure enough, the
-10V rail showed 0V across it. I probed different points on the negative
regulator. This seemed to be functioning correctly: the opamp had a
diode forward voltage drop across it's inputs and was driving the output
to about 17V. The voltages at A23Q1 (the darlington that provides
current for this rail) were C=17V, B=1.6V and E=250mV. However, the
voltage across the current sensing resistors was only about 250mV (so
the current through them was about 600mA). I believed this meant A23Q1
wasn't able to source enough current and was therefore the faulty
component.

My next move, in retrospect, I believe was stupid. Thinking this
transistor was at fault, I attempted to supply the -10V externally. The
unit began to smoke and smell burnt and I pulled the power.

Now if I turn on the unit, the -10V rail sometimes comes on and other
times does not. Unfortunately this makes it a bit tricky to diagnose
since I can't just pull assemblies until the supply comes back up.

Thoughts on how to proceed? I'm concerned I did some serious damage
supplying external power.

Thanks
Matt
Re: What would happen if I let the battery in my HP 54622D oscilloscope run down?

 

On Monday 17 January 2022 01:54:24 pm Glen Slick wrote:
Note that the battery is a coin cell with tabs that is soldered to the
main PCB. Would have been a lot nicer if they had used a battery
holder for the coin cell.
Some years back I was involved in the repair of a lot of electronic musical instruments, and encountered this situation quite often. Worst one was a box that was meant to be hit with a drumstick! Very often it wasn't that the battery had failed but that one of the tabs had broken. I routinely replaced these with a coin cell that went into a holder that was soldered in place plus which had three additional (plastic) support points. Never had an issue with one of those coming back after that.


--
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
Re: What would happen if I let the battery in my HP 54622D oscilloscope run down?

 

On Mon, Jan 17, 2022 at 10:34 AM Steve via groups.io
<sholland@...> wrote:

I understand that bit. On the HP 3478A DMM replacing the battery without maintaining voltage in the circuit caused loss of calibration and you have an inaccurate meter. If I just remove and replace the battery in the HP 54622D oscilloscope do I also lose calibration or something else important? Is it just keeping user preferences? My approach to replacement will depend on what is lost when the battery is disconnected.
This has come up many times on the eevblog forum. You can search for
threads about it there. For example:


The consensus there seems to be that the dead battery can be replaced
without doing anything special to backup memory contents. After doing
so a user calibration should be performed.

Note that the battery is a coin cell with tabs that is soldered to the
main PCB. Would have been a lot nicer if they had used a battery
holder for the coin cell.

I have a 54621A with a dead battery. I haven't been motivated to
replace the battery in it yet.
Re: HP 8594E - AMPTD CAL : GAIN FAIL FOLLOWED BY "CAL SIGNAL NOT FOUND"

 

Was using the wrong adapter which was also defective.
/g/HP-Agilent-Keysight-equipment/message/121755
Re: [SOLVED] HP 8594E - AMPTD CAL : GAIN FAIL FOLLOWED BY "CAL SIGNAL NOT FOUND"

 

Without knowing, I was using a 75 Ohm N to BNC adapter which was ALSO defective.

CAL routine is now successful.
Re: What would happen if I let the battery in my HP 54622D oscilloscope run down?

 

If the battery runs down it will eventually leak and ruin the scope or DMM. I suggest you replace it.
I understand that bit. On the HP 3478A DMM replacing the battery without maintaining voltage in the circuit caused loss of calibration and you have an inaccurate meter. If I just remove and replace the battery in the HP 54622D oscilloscope do I also lose calibration or something else important? Is it just keeping user preferences? My approach to replacement will depend on what is lost when the battery is disconnected.
Re: HP Diode ID Help

 

Just some additional information

The individual diodes for this pair are found under part number 5082-2303.
HP crosses that diode directly to a 1N5167.

?

5082-2303 diode specifications:

??????????? Minimum breakdown voltage VBR (V): 20

??????????? Minimum forward voltage VF (mV): 400

??????????? VF = 1V Max at forward current IF (mA): 35

??????????? Maximum reverse leakage current : IR (nA): 500 at VR (V): 15

??????????? Maximum capacitance CT (pF): 1.0

??????????? ???????????

5082-2308 diode pair matching test conditions:

¦¤³Õf at If = 0.75V at 20 mA

¦¤°äo at f = 1.0 MHz

Greg
Re: HP 8510 C with HP 8511B

 

Because control boards are same, it must be configured by switches?at the A3 board.
You can find proper settings there, at block diagrams (pages 49-51)
Re: HP 8510 C with HP 8511B

 

¿ªÔÆÌåÓý

Thanks for the info i have the splitter switch coming from an HP8517 , i will open my HP8511 to see the control board.

IW1EPY

Gianni

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Da: [email protected] [mailto:[email protected]] Per conto di ??????? ?????
Inviato: domenica 16 gennaio 2022 09:11
A: [email protected]
Oggetto: Re: [HP-Agilent-Keysight-equipment] HP 8510 C with HP 8511B

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You can find Test sets schematics at artekmanuals, inside Hewlett Packard 8510A Operating, Service-V5 file, which contains schematics for testsets (but only for "A" versions of 8511-8515).

Also, you can download 8517 service manual from Keysight (without schematics, but with part list and block diagrams)

As I see, control board for 8511 and 8517 is a same, but you need 08513-60011 or 08517-60001 Attenuator|switch driver (not shure, which one).

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