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  1. HP8924-Family-Spectrum-Analyzers
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8920B and RFDIAGS2 error

 

Hi All,

Cleaned off the bench and took 83206A off the 8920B - Thought it would be a good idea to run the diagnostic programs that are on the system ROM - Unit passes power self-tests but when running RFDIAGS2 I'm getting errors during the Output section of the test program.

The first error is in the "Output Detector, Detector Caps" phase. The 4 tests check two caps, C419 & C418 both in and out of the circuit together and individually. I get the same result for every test indicating an actual Vdc of 0.038. The diagnostic suggests that the path is A25J55 to A25J56 - From poking around this seems to be W13, a semi-rigid short jumper.

The next set of errors is in the "Output Frequency Range, Loop Closed" phase. It shows a value across the frequency range of 0.038 to 0.041 and again suggests W13. Finally, there are errors in "Bandwidth Control" again pointing to W13.

From reading it seems that W13 is a bit of a known problem child but before opening the unit up and trying to gently clean it, I wanted to ask the group if this could be a false flag from removing the 83206A? Would they have removed that jumper in the expectation that the path would continue through the external 83206A?

Any comments, thoughts, or suggestions are appreciated.

Thanks,

TonyG
 

As an FYI for anyone looking for the answer on this - Yes, it appears that if your 8920B comes with the option that works with an 83206A (or I would assume any of the other test sets), then W13 will actually be taken to the back of the unit.

I used one of the cables that connected those ports to the 83206A to connect the appropriate ports and my unit passed the RFDIAGS2 tests.

TonyG
 

This is common issue to the 892X series including the 8920A and 8921A.

If fitted with certain options they may require a jumper on the rear for the unit to be operational without the external adapters.

Not that uncommon on HP Agilent gear? ...often needs a jumper for the reference and LO signals.??

Used to see a lot of gear being sold as defective when the rear jumpers were missing and most likely the cause of the problems.

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