Hp 8594e Cal res bw ampl fail

[AwArD_RzD]

Hi

I just bought on Ebay an HP 8594e SA (my first SA) , the unit is in excellent exterior condition and it's stated in working condition, but i have some problem with the ampl calibration test and i hope someone here will be enough familiar with this unit to be able to help me.

After the unit is on for about an hour i did the confidence test and the frequency cal test and i got no error but when the Ampl cal test run it's stop at the 1Khz BW and say CAL RES BW AMPL FAIL  SRQ 110. I checked in the trouble shooting manual and this can be 3 thing, Filter need calibration, a board is fry, or it's just a lack of calibration correction in the memory. In the trouble shooting manual this is the text about that

CAL: RES BW AMPL FAIL (H)
During the CAL AMPTD routine, the insertion loss of a resolution
bandwidth filter, relative to the amplitude of the 3 kHz resolution
bandwidth filter, was greater than 2.2 dB.
Related Assemblies
A7 analog interface, A11 bandwidth filter, A13 bandwidth filter, A14 log
amplifier/detector.
Troubleshooting Hints
The CAL AMPTD routine will stop at the resolution bandwidth that
failed. If the A11/A13 bandwidth filter assemblies require realignment,
use the crystal and LC bandwidth filter adjustment procedures in
Chapter 2.
If a defective bandwidth filter board is suspected, refer to “IF
Power-Level Measurement” in Chapter 5.

i found in the Agilent forum this discussion http://www.home.agilent.com/owc_discussions/thread.jspa?messageID=59931&tstart=0 but it seem to be more related to the option 130 (which i have but can't test that since it stuck at 1khz).Now if anyone can tell me if there a easy and not intrusive test or thing i can do to be sure it's only a calibration issue, i still have some time to return the unit but i don't want to pay someone half the price i paid to troubleshoot this unit to found it was a hardware failure.

When i test manualy i can see a drop in the 1 khz and 300 hz range but this disappear if i enable the correction option in the cal menu. So i'm stuck here, calibration or hardware error?? since i still get an error for the AMPL cal test.



Thanks in advance for your help.

[willb]

My 8591A had the same issue. Mine wasn't failing at the 1Khz RBW filter, I think it was the 30Khz(can't remember). I rigged up some LC shorting crystals as described in the manual, and carried out the adjustments of the A11/A13, basically peaking them for max amplitude. My SA now passes it's self cal perfectly every time.

[AwArD_RzD]

I manually tested all the range multiple time under 1khz and i found all the result is way off and i can repeat these result so no intermittent drift here. 

The 300 Hz show -24.91 dBm
The 100 Hz show -26.54 dBm
The 30 Hz show -35.30 dBm.
these should be around -20 dBm (+- 2.2 dB) as the troubleshooting guide say.

I did more research today and the little info i found is when the problem is under the 1khz range, it's the add on board fault and there no adjustment. The board should calibrate itself (in theory) if the information i found are true.

Thanks for the info Willb. I was near to try this route to see if this change something but the seller replied and he offer a replacement, (same model, same option) so i will wait to receive the other unit. Good to know if i get this error in the future for the upper RBW this can be re calibrated with this procedure.

If i have some feedback about this (if the seller give me news about the problem) i will update this thread for future people who might have this issue.

[dxl]

Hi,

did you ever fix that issue? I'm having the same problem with a HP 8596 SA. All BWs are fine, but the 1KHz RES BW Amplitude is off by around 6db. Would be interested how you fixed it.

Thanks

[dxl]

Seems like the 21.4MHz crystal filter on my Bandwidth Amplifier Board is broken. The Agilent Part number is 0410-2118, but it's no longer available. Does anybody know the specs of those filters?

Thanks

[AwArD_RzD]

I returned the unit and the guy never told me the problem with the SA and the only person who was able to help me with that told me, if this is a crystal/filter issue you need to replace them with a matched batch. Recently i saw somewhere there some transistor who can cause this issue but i don't remember where i saw that, if i find it i will post the link.