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Date
Re: Where to connect the efc input on a 10544A?

 

It's up to you. How close do you want to be abl to set it?

A +-5V supply an 10 Turn pot is not too hard to do. Personlly I've used a isolated 12V output DC-DC converter with lots of filtering, a 10V reference IC? a 1:1 resistive divider connected to the EFC common, and a 10k 10 tun pot.

Robert G8RPI
Re: Fixing a sick 4332A LCR meter

 

Hi Joel,

I might have meant R36. All I have to go on right now is the awful manual scan that Keysight hosts. It's very hard to read, and some of the key diagrams are illegible. I suppose I should see if Artek has a scan, or try to find a manual on ebay.

I may contact you as I continue to troubleshoot; thanks for the tips.

Sean


On Wed, Apr 1, 2020 at 06:05 AM, Joel Setton wrote:
Hello,

I also have a 4332A and the manual, too. I looked at the A4 schematic and found that R35 on A4 is a 9.09K resistor, not 100 ohms. I don't see how a 9.09K resistor could burn, you'd need something like 60V or more to burn it. There's no high-voltage source in the 4332A so I don't understand how R35 could overheat.

I would first suggest disconnecting the four input signal leads to A4: the HIGH and LOW leads, and the orange wire and the white-red-green wire. Then you can test the various voltages which are shown on the A4 schematic to look for a failed part.
And please let me know, I'm happy to help. The 4332A is quite a neat instrument !
Joel Setton
Re: HP 3455a DVM repair

 

The 3455A was a dinosaur when it was first released.

The 3455A and 3456A were sold side by side, with the
3455A being about twice as expensive as the much more
capable 3456A. The 3455A's interesting feature was
it was supposed to be cheap to calibrate. All you
had to do to do a complete calibration was to unplug
the module in the back panel, and replace it with a
recently calibrated module. The idea was you could
order up a calibration by mail, and return your old
calibration module as a core... never having to send
the full meter in for calibration.

Interesting idea, but surely not worth twice the price
of a 3456A.

I say it was a dinosaur, because it used all small
scale logic rather than large highly capable hybrid
circuitry, like the 3456A. It should be much easier
to repair, but it should also be much less reliable.

And, that is my experience with the two units.

-Chuck Harris

paul swedberg wrote:

With respect to the 3455 and 3456 the difference is night and day. I have
numbers of 3456s and was given a seriously troubled 3455. Quite a
interesting meter.
Replaced at least 11 actually malfunctioning chips on the logic board. The
logics simple so easy to verify the chips were bad. No shot gunning
involved. Never really did get it working but ended up with a different
3455 that needed help and the AC board and it is in fine shape. With
respect to the old 3455 it has both a logic and voltmeter issue. The 3455
uses an unusual processor and teh DVM uses the same proc and a masked eprom
that is known to go bad. It acts as a state machine.
The 3456s are losing there eproms and copies can be found on the net. Thank
heavens.
Regards
Paul
WB8TSL
Re: HP 3455a DVM repair

 

With respect to the 3455 and 3456 the difference is night and day. I have numbers of 3456s and was given a seriously troubled 3455. Quite a interesting meter.
Replaced at least 11 actually malfunctioning chips on the logic board. The logics simple so easy to verify the chips were bad. No shot gunning involved. Never really did get it working but ended up with a different 3455 that needed help and the AC board?and it is in fine shape. With respect to the old 3455 it has both a logic and voltmeter issue. The 3455 uses an unusual?processor and teh DVM uses the same proc and a masked eprom that is known to go bad. It acts as a state machine.
The 3456s are losing there eproms and copies can be found on the net. Thank heavens.
Regards
Paul
WB8TSL
Re: Fixing a sick 4332A LCR meter

 

Hello,

I also have a 4332A and the manual, too. I looked at the A4 schematic and found that R35 on A4 is a 9.09K resistor, not 100 ohms. I don't see how a 9.09K resistor could burn, you'd need something like 60V or more to burn it. There's no high-voltage source in the 4332A so I don't understand how R35 could overheat.

I would first suggest disconnecting the four input signal leads to A4: the HIGH and LOW leads, and the orange wire and the white-red-green wire. Then you can test the various voltages which are shown on the A4 schematic to look for a failed part.
And please let me know, I'm happy to help. The 4332A is quite a neat instrument !
Joel Setton
Where to connect the efc input on a 10544A?

 

Hi,

So while we are stuck at home and have nothing to do but play with all
the instruments I started a project to build a distribution amplifier
for 10MHz reference. I do have a GPSDO, but that is cumbersome to use
as I don't have a good view of the sky from my room. So Instead I
decided that I build a two-in-one distribution amplifier + OCXO
reference, as I have a spare, well aged 10544A laying around. (I'll
share the design if it ever gets done.) That would be plenty of enough
precision for what I do, the GPSDO could be used to calibrate it once
in a while. That should be plenty of enough for me, as I would be
driving signal and function generators from it, nothing extreme
time-nuttery.
So my question is: Is it worth to connect the EFC input of the OCXO?
The datasheet says it has about 1 Hz range, but then I would need to
provide the -5/+5V supply for it, preferably with some good quality
reference. I know that this input is not connected in the 5335A for
example, only the "coarse" adjustment is used.
I guess it is is good for the 5335A then it should be good for me, but
on the other hand, why not make some overly complicated thing when we
finally have time for it :-)
So basically, my question is would you recommend to simply short the
EFC input and only have the coarse adjustment or should I take the
extra effort to have this fine adjustment? Would it have any drawbacks
if I do?

Thanks.

Szabolcs
Re: HP 3325A - with a short in board A14 negative 15V supply

 

This issue is almost always a shorted tantalum capacitor on the A14 board. Other suspects include the -15V zener diode or the Opto-couplers (4-pin DIPs) on the A14.

This can be an issue with the A3, A14 of A21 boards. You can verify that the A14 is the issue by temporarily disconnecting the ribbon cable supplying the A14. If the unit boots (with errors), then something on the A14 is shorted.

Perform a visual inspection of the A14 tantalums. The bad part is usually discolored from heat damage.

It's best to use a thermal IR camera to see which part is glowing, but lacking such, you can de-solder and lift one end of each tantalum capacitors along the -15V rail on the A14, then measure the resistance on the lifted diode, and on the -15V rail. The shorted part will eventually show itself using this method.

Hope that helps!

Joe, KN5U
Re: HP 3325A/B Option 002 HV output kit - who wants one?

 

¿ªÔÆÌåÓý


I would like two boards, please.


Tom Dawson

On 3/27/2020 11:19 AM, Jared Cabot via Groups.Io wrote:

Ok, let's make this the official thread for the 3325A/B Option 002 HV Output kit thread.

I'll get a batch of the latest boards spun up and finalise the documentation etc. once I have a full head count. Maybe I'll give it a week for people to get in on this first batch before I place the order.

?

The PCB is almost identical to the original board, just updated slightly for currently available parts. It will be gold plated with no top solder mask or silk screen like the original (It seems to not like sticking to the gold for whatever reason), so it'll end up as close a replica as can be.
Also, the dual transistor on the input will be replaced with two somewhat matched discreet transistors, as the cross referenced part from the original design is a little expensive.

I'll offer bare boards complete with all documentation, or a full kit including all parts minus the RF shield as I don't have the means to make them in any quantity unfortunately. I will provide the template so you can make your own from a scrap of thin aluminium though.
I will also provide some thin coax and right angle RCA jacks to build your own interconnects too.


Postage will be a flat fee worldwide and included in the total cost. I am still finalising the final cost, but I'm practically certain that it will be no more than US$50 all inclusive for the kit. The bare PCB will cost about $7 plus post (once I work out what a registered envelope costs to send...)

Here's the eevblog thread that needs to be updated. I'll do that once I get the latest boards back and have one assembled and tested to be 100% sure no bodge wires are needed. :)


So, sound off who wants one. :)
The following people have expressed interest so far, please confirm or correct as needed:


Mac Perkins: Board or Kit
Tom WA3PZI: Kit
JL Trantham: Kit x2
Bruce at westcut: Kit
Daun Yeagley: Board
Dave Wright: Kit
Joe KN5U: Board or Kit
Kerry Burns: Kit


Virus-free.

Re: HP 3325A/B Option 002 HV output kit - who wants one?

 

Please add me as well, 5 boards

Thank you,

Hal
Re: HP 3325A - with a short in board A14 negative 15V supply

 

Hi,

I doubt it's the PSU, I would still suspect one of th the caps on the
A14. FOr a very simple check, you can measure resistance on the -15V
input of the board, if there is a dead short, that would show up. Or
you can supply the power from external source and see if that help and
that would also enable you to measure current.

Szabolcs

Maurice Smulders <Maurice.Smulders@...> ezt ¨ªrta (id?pont: 2020.
¨¢pr. 1., Sze, 7:40):


Is there a known issue where there is a problem either in the PSU or Board A14.

Once A14 is connected (ALL other connectors are disconnected) the unit doesn't turn on (No LEDs)
No caps look to be bad - haven't had time to dig in deep...
What currents should the PSU be able to supply on +/- 15V and +5V, so i can test it with a resistor to see if the PSU is bad?

-Maurice
Re: HP 3325A/B Option 002 HV output kit - who wants one?

 

Please add me in for one board. Don't know if I can fix my broken unit yet...
HP 3325A - with a short in board A14 negative 15V supply

 

Is there a known issue where there is a problem either in the PSU or Board A14.

Once A14 is connected (ALL other connectors are disconnected) the unit doesn't turn on (No LEDs)
No caps look to be bad - haven't had time to dig in deep...
What currents should the PSU be able to supply on +/- 15V and +5V, so i can test it with a resistor to see if the PSU is bad?

-Maurice
Re: HP 3325A/B Option 002 HV output kit - who wants one?

 

I'd like a board. I have a 3325A - with a problem likely in board A14.
Fixing a sick 4332A LCR meter

 

Hi all,

I recently purchased a very nice looking 4332A LCR meter. It's in great shape cosmetically, but does not work properly. Power rails are in spec, voltage and ripple in or well within tolerance. Inside is clean, except on the A4 amplifier board. R35 (a 100 ohm 1/8W metal film) was cremated and reading well over 1K. No other components are visibly damaged. I replaced it with a 100 ohm 1/4W metal film resistor I had on hand, which did little. The new resistor is not getting hot at all, so perhaps someone overloaded it? In any case, the signals that the service manual says should be present on the various test points are either not present or of much smaller amplitude than the service notes call for. I'm at a loss for what to try next. It seems to me someone cooked that amplifier setup pretty good.

Anyone familiar with these little units? I'd like to get it working again but I have a feeling if any of the multilegged semiconductors used in the amplifier circuits are damaged, they are unobtainable.

Thanks,
hp83592A

 

Hi gang,
??????????? Still trying to fix my 83592A plug in with uncontrolled rf output power,
Biggest problem is trying to isolate what the actual problem is.
Initially thought it was just an ALC (A4) problem but then found that i had multiple output peaks between? 10mhz and 2 ghz but they disappeared after that up to 20ghz.
more checking revealed that the same problem appeared on the auxillary output on the rear of the plug in, where the nominal 0dbm output is only -10dbm and as far as i am aware the rear output is the output of the yig in the 3 to 6 ghz range and? should be 0 dbm.
another observation is that the yig output varies considerably as it sweeps the 3-6 ghz range.
So i am beginning to think the yig or it's controller may be faulty.
Any suggestions?
Ken
VK2TKE
Re: HP 3455a DVM repair

Bob Albert
 

I reseated the three boards and poked around behind the display to no avail.? Not sure if anything changed but now what I get is OL on power up until I push buttons then it reverts to all zeros.? When I change ranges the number of zeros changes.? The trigger LED flashes when it should.? I push TEST and it cycles from 11 down to zero and then goes back to 'operating' such as it is.? So the display is okay, I think.? The voltages seem okay also.

On Tuesday, March 31, 2020, 08:55:22 AM PDT, Bob Albert via Groups.Io <bob91343@...> wrote:


I will look at the connectors.? The voltages are okay, at least the ones I measured.? I am thinking maybe the unit is working but the data isn't reaching the display.? I will let you know.

Bob

On Tuesday, March 31, 2020, 07:41:22 AM PDT, n4buq <n4buq@...> wrote:


I don't know how similar the 3455A is to the 3456A, but I seem to remember a similar issue I had with a 3456A where merely reseating the ribbon cable connector to the display board fixed some odd display issues.? Again, not sure if the 3455A has a similar connector but it's worth a try if it has one.

Thanks,
Barry - N4BUQ


----- Original Message -----
> From: "Bob Albert via Groups.Io" <bob91343=[email protected]>
> To: [email protected]
> Sent: Monday, March 30, 2020 9:23:03 PM
> Subject: Re: [HP-Agilent-Keysight-equipment] HP 3455a DVM repair
>
> Wow Ed you are going too fast for me!
> Yes I heard relays clicking.? Now I get, besides the zeros, a display LL
> whatever that means.
> It is sitting here with me, not yet on the bench.
> Bob
>? ? On Monday, March 30, 2020, 06:55:59 PM PDT, Ed Giaimo
>? ? <edgiaimo@...> wrote:
>
>
> A lot of digital things are working if self test responds and you get zeroes
> on the display. if the auto cal light is on and the processor reading
> inputs, you should hear a regular pattern of relay clicking. Any noises?
>
>
> Check the power supply output voltages, including the 10V reference on the
> A10 analog pcba.
>
> On that same A10 board, JFETS manage signal attenuation driven by open
> collector 7406 ICs U4-U9 from latches U11-U17. I have found broken 7406s
> that could not pull to ground and latches that were not driving the 7406
> buffers. Most common is one or more damaged JFETS Q1, Q2, Q13-Q16 exposed to
> the input bus. It is fairly easy to check voltage levels when the unit is
> cycling thru attenuator settings during auto cal.
>
>
>
>
>
>
>
>


Re: HP 3455a DVM repair

Bob Albert
 

I will look at the connectors.? The voltages are okay, at least the ones I measured.? I am thinking maybe the unit is working but the data isn't reaching the display.? I will let you know.

Bob

On Tuesday, March 31, 2020, 07:41:22 AM PDT, n4buq <n4buq@...> wrote:


I don't know how similar the 3455A is to the 3456A, but I seem to remember a similar issue I had with a 3456A where merely reseating the ribbon cable connector to the display board fixed some odd display issues.? Again, not sure if the 3455A has a similar connector but it's worth a try if it has one.

Thanks,
Barry - N4BUQ


----- Original Message -----
> From: "Bob Albert via Groups.Io" <bob91343=[email protected]>
> To: [email protected]
> Sent: Monday, March 30, 2020 9:23:03 PM
> Subject: Re: [HP-Agilent-Keysight-equipment] HP 3455a DVM repair
>
> Wow Ed you are going too fast for me!
> Yes I heard relays clicking.? Now I get, besides the zeros, a display LL
> whatever that means.
> It is sitting here with me, not yet on the bench.
> Bob
>? ? On Monday, March 30, 2020, 06:55:59 PM PDT, Ed Giaimo
>? ? <edgiaimo@...> wrote:
>
>
> A lot of digital things are working if self test responds and you get zeroes
> on the display. if the auto cal light is on and the processor reading
> inputs, you should hear a regular pattern of relay clicking. Any noises?
>
>
> Check the power supply output voltages, including the 10V reference on the
> A10 analog pcba.
>
> On that same A10 board, JFETS manage signal attenuation driven by open
> collector 7406 ICs U4-U9 from latches U11-U17. I have found broken 7406s
> that could not pull to ground and latches that were not driving the 7406
> buffers. Most common is one or more damaged JFETS Q1, Q2, Q13-Q16 exposed to
> the input bus. It is fairly easy to check voltage levels when the unit is
> cycling thru attenuator settings during auto cal.
>
>
>
>
>
>
>
>


Re: HP 3455a DVM repair

 

I don't know how similar the 3455A is to the 3456A, but I seem to remember a similar issue I had with a 3456A where merely reseating the ribbon cable connector to the display board fixed some odd display issues. Again, not sure if the 3455A has a similar connector but it's worth a try if it has one.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Bob Albert via Groups.Io" <bob91343@...>
To: [email protected]
Sent: Monday, March 30, 2020 9:23:03 PM
Subject: Re: [HP-Agilent-Keysight-equipment] HP 3455a DVM repair

Wow Ed you are going too fast for me!
Yes I heard relays clicking.? Now I get, besides the zeros, a display LL
whatever that means.
It is sitting here with me, not yet on the bench.
Bob
On Monday, March 30, 2020, 06:55:59 PM PDT, Ed Giaimo
<edgiaimo@...> wrote:


A lot of digital things are working if self test responds and you get zeroes
on the display. if the auto cal light is on and the processor reading
inputs, you should hear a regular pattern of relay clicking. Any noises?


Check the power supply output voltages, including the 10V reference on the
A10 analog pcba.

On that same A10 board, JFETS manage signal attenuation driven by open
collector 7406 ICs U4-U9 from latches U11-U17. I have found broken 7406s
that could not pull to ground and latches that were not driving the 7406
buffers. Most common is one or more damaged JFETS Q1, Q2, Q13-Q16 exposed to
the input bus. It is fairly easy to check voltage levels when the unit is
cycling thru attenuator settings during auto cal.
Re: HP 8590L 1.8GHz SA possible frequent issue ? Does not power up

 

The PSU's are not unknown for failing.? I've known of three 859x SA's
that have failed that way in recent years.? Never heard if any were
resurrected or not.

I think the PSU's are a bought in product, not of HP/Agilent
manufacture, from other peoples comments on this (and other) list(s)

Dave G0WBX.

--
Created on and sent from a Unix like PC running and using free and open source software:
Re: HP 3455a DVM repair

Bob Albert
 

Wow Ed you are going too fast for me!

Yes I heard relays clicking.? Now I get, besides the zeros, a display LL whatever that means.

It is sitting here with me, not yet on the bench.

Bob

On Monday, March 30, 2020, 06:55:59 PM PDT, Ed Giaimo <edgiaimo@...> wrote:


A lot of digital things are working if self test responds and you get zeroes on the display. if the auto cal light is on and the processor reading inputs, you should hear a regular pattern of relay clicking. Any noises??


Check the power supply output voltages, including the 10V reference on the A10 analog pcba.

On that same A10 board, JFETS manage signal attenuation driven by open collector 7406 ICs U4-U9 from latches U11-U17. I have found broken 7406s that could not pull to ground and latches that were not driving the 7406 buffers. Most common is one or more damaged JFETS Q1, Q2, Q13-Q16 exposed to the input bus. It is fairly easy to check voltage levels when the unit is cycling thru attenuator settings during auto cal.
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