HP 8590a error messages

Hi everyone,

I'm the "happy" new owner of an used HP 8590a spectrum analyzer, you know...one of those as an radio-amateur I've wanted all my life and finally could afford one (because it's old)

But - I've seen a couple of error messages that reoccur now and then, not when warmed up...but before that...and it won't start properly before these are gone:

ADC-2V Fail ADC-GND Fail

What are these? I've searched half the net for this, and there's no service manual for download at agilent these days but I've found "similar" models in the (E) series, and it says it's power supply related.

Any ideas?

Cheers.

I have a 17MB .pdf copy of the 8590a component level information package which includes a schematic. The part # is 5963-2591, and the document is dated 1997. Would this be of use to you?

If so, I uploaded a copy to my webspace - you can download it here:

Thanks for your suggestion,

Ack...

It finally said goodnight today as it won't get past the ACD V2 Failure or GND fail thing..

I opened it and found that the power-input on the instrument itself have 6 checkpoints with LEDS on them.

5v , 12v, 15+, 15-, 5v, 5v.

two are not lit anymore, one is -12.8 v and one is -15 volt (they where lit before so I actually watched them die.

I opened the powersupply to check for dead-connections and bad solder, and there where plenty of "dry" solder areas, so I re-soldered the whole powersupply.

Unfortunately that didn't improve a thing. So it's obvious that the - "minus" voltages are gone.

There are "Some" life in them, but it's very low and weak it's -0.04v for one of them and -0.11v on the other.

Any ideas?

**THE-RFI-EMI-GUY** wrote:

Thanks a lot for this information. Unfortunately it doesn't contain the Power-supply schematic, but it does contain literally anything else, so it's bound to be useful at some point. Again - thanks for this one!

Sorry that the schematic I had didn't have the power supply section (strange, that...) To start with, I would try to isolate the power supply from the rest of the unit, and see if your voltages return. If they do, then you're most likely looking for a shorted component elsewhere.

How could you have known? Over 400 pages in that manual, huuuge! ;)

Anyway, I did remove the unit and did the following things:

- Resolder all solder points. Judging from the "dry solder" it was badly needed. Unfortunately it didn't resolve the issue.

- Removed 2 suspicious Zener diodes, you know...for some of the minor supply terminals like (-) voltages these could be used, but it's a rather complex unit so I don't think so, anyway - they worked fine as far as a normal diode-tester could tell.

The power supply IS blown, but where... It's a very complex SMPS unit with at least 3 transformers and 2 minor ones (5 in all), it have some kind of "SMD/SMT" microcontroller that sits on it's own PCB.

I've checked all resistors, and most capacitors, they all seem to work just fine. That basically leaves the transformers and their transistors/IC's/Thyristors etc. I don't know much about SMPS clipping techniques so I have NO clue what could be wrong.

Again - thanks for your ongoing tip / assistance.

(Anyone - feel free to join in, I'm lost and

5-days after buying my dream in 25-years first spectrum analyzer, I'm kind of ...put off)..

What are the numbers on the micro controller? Are you able to get a datasheet?

How did you check the capacitors?

Trace the circuit back from the faulty output(s) looking for shorted or open semiconductors. Unfortunately, It may be necessary to remove them from the circuit to do a valid test.

Would it be possible for me to download a copy too please?

I have an 8594EM with tracking generator which is very similar to the

8590. It works fine apart from a sticky coaxial relay on the tracking generator output attenuator.

I also have a 54542A 2Gsa/s 4-channel oscilloscope which recently died after a thunderstorm. It powers up, but only gets as far as the boot menu. I suspect corrupt flash memory. I have the service manual it came with, but this doesn't go into component level detail and the diagnostic flow chart does not cover my particular fault. I would be very interested in getting more detailed information about this before I start trying to fix it.

John

Sure - I just re-posted it for you.

Many thanks - John

As it turns out - there's different versions of the HP 8590A, I had no idea there where so many of the same (A) Series. The schematics aren't matching the analog interface (Part no: 08950-60001. But thanks anyway, it might be of use to someone else. Thanks for the kind attention though.

Anyone else know where I can get an Analog-Interface Board (08950-60001) for an HP 8590A Spectrum Analyzer?

The error I mention earlier wasn't the power supply after all, it just failed with ADC V2 FAIL to GND because of a short in the Analog Interface section. The shorted circuit seems to be some kind of "PAL" chip with proprietary programming from HP, so it's not even close to possible to get from them these days. If anyone have the knowhow to extract or know the functions of the 22 (PAL) chips (Called PIM) on this board any information would be appreciated. I'm also willing to purchase this board if you have one for sale within reason.

The failing voltage is -15 volt, and removing the Analog-Interface board removes the error messages. I've checked -15v to ground and it's indeed shorted - but it seems that the only electronics utilizing the Minus (-15) volt is some kind of proprietary chips from HP

In advance - thanks to anyone for both reading this and future attention.

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JW do you have anyth>:

*** ISSUE RESOLVED ***

I think I owe it to the newsgroup and people who might have the same problems with their HP's to know the solution and outcome of this case:

The ADC-2V Fail to GND is a short-circuit between V2 - output of the PSU and the GND (Ground). The V2 output is MINUS 15 volts.

The cause of the short was on the board called 08590-60001 (there are various revisions of this board!) was a short-cirucit in three electrolytes 6.8mF 35v located and directly connected to the -15v lead to GND (they're easy to locate - -15 is written directly on the PCB so just follow the main lead)

Removing these and replacing with 10mF worked like a charm, the analyzer works better than it did originally, doesn't even get the curve-fail error anymore.

Hope this message helps anyone else out there at some point in time. Thanks to all who gave help with supplying Manuals and to all who gave input on the issue.

(And I'm no longer looking for an replacement board!)

JW, Could you repost that manual so I could download a copy

Andrew