HP 8920B service monitor repair(It's Alive!)

[mojoe]

If you got Option 55, then you really lucked out. It wasn't very commonly installed, as your average two-way radio shop didn't need anything below VHF.

[TheSteve]

Yep, it was the only reason I sold my 8921A.

[VE2UM]

Effects of excessive reverse energy into the DUPLEX OUT port (probably a 40 Watt mobile...)

Ugly, the board is not recoverable (burnt trace)...

[BFabio]

Hello, I have an HP8920A that has an error in the measurement of Spectrum Analyzer, measuring 0dBm and making a bridge between the duplex out connector and antenna on the screen to the right lvl measures -3.38 dBm, so it has that errror.
I know it is an amplifier that is running out and I need help to know what it is and if someone has the scheme.
Thank you.

[basvk]

Hi all,

Anyone know about option-compatibility between the different types?

Or, more specifically, would an 8922 spectrum analyzer module work in an 8920?

[EIKA]

Hi guys!

I see that a lot of HP 892x fans here, and I want to ask you one question. It's funny a bit. Here is it's own separate thread https://www.eevblog.com/forum/repair/fallen-off-metal-part-inside-of-hp-8921a/

Please advise if you know what is this.

[OverclockedPizza]

I have an 8920B that has the error "ROM Checksum Error" when I put switch 3 open to boot from OTP.
It's likely been unused for nearly 20 years. Is it just bit rot? Would updating/reflashing the firmware fix that?
And if so, does anyone have a flash card they would sell me? (I'm in Canada) I don't even see one on eBay.

[TheSteve]

The 8920B doesn't have OTP memory, it is flash based. I do have a firmware update card or two around.

[Kerlin]

I do wish that it provides you with what you whish, but I gave up on this type of old clunker gear.I had literally tons of it Threw it all out. It needs continuous care and repair, a life time job.

I previously worked in RF test and repair as as a tech.
 Then later as an Engineer in a calibration, cerification and repair laboratory for this equipment and other types.
I repaired this stuff untill the owners and threw it out and I took a pile of it home.
It's had a life time of many many decades long of being bashed around by employees who don't own it or care about it, treated it like that myself.
 It will show that, was thrown out for a reason.
In the cal lab my employer had the sense to only use current up to date gear that didn't need continous attention.
The memory was removed for a reason I will leave it up to you to guess why.
It will give you plenty to do, till you eventually run into a spares problem.

[alocam]

Hello, I have an HP8920A and all of the sudden the power supply released magic smoke. I repaired it but there are plenty of RF Tests errors (around 22) coming from input section. The unit has been turned off for years, and I wonder if anyone has experience with input section having tantalum or electrolytics that might have failed due to long storage time.

Error count is going down after running several RF test passes, and some rejected values are just below acceptance threshold, only a few of the test results differ greatly from expected values. I will have to write down a list of errors, as there seems to be no way to extract data other than printing through HPIB.

Any comments will be appreciated.

Regards

[Robert763]

Hi all,

Anyone know about option-compatibility between the different types?

Or, more specifically, would an 8922 spectrum analyzer module work in an 8920?

Very old thread I know but I can give an answer. It may be useful to others who find this thread.
The SA module in the 8922x is slightly different to that in a 8920x. If you fit a 8922x SA into  8920x the test set will give a configuration error message. If you ignore this the test set and SA will work but SA calibration may be off. This is true for ANY 892#x SA module swap. to get calibrated results you need to load the calibration factors for that modue into the test set. AFAIK the only way to do this is by memory card.