Hey y'all!? I was hoping to get some help or clarification on the start-up calibration procedure for the HP 8557A/8558B spectrum analyzer plug-in.? First, I did not get this unit in working order and I have completed a lot of restoration on it. Also, I've never used/owned a spectrum analyzer before this unit, which likely contributes to the trouble I'm having.?
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The problem I'm having is with the linear/10 dB/div calibration.? In this step, the manual states that you should be able to adjust both the Linear and 10dB/div by adjusting the 'Reference Level Fine' knob to get the 250MHz calibration signal peak all the way to the top graticule line.? But I can't do that without adjusting the 'Coarse reference level' knob (the manual does allude to using the coarse reference level knob for this adjustment in the troubleshooting section of the manual).? The manual states if this adjustment cannot be done, then check the linear/log amplifier board A11, but I can't find any issues there.
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My question is, can anyone who owns one of these make sense of the manual?? Or possibly have they confirmed an issue with the way it is described?? It seems a blog on repairing this instrument (pretty much the same repair I had to perform) also seems to allude to issues with the manual.? My cal signal and amplitude for both linear and log modes looks similar to his (blog link here; scroll to the bottom )
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Thanks in advance for your help!
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-Frank
Frank Mashockie