I have an 8665B with what I can best describe as a noisy signal; three side lobes to each side of the carrier, before disappearing into the noise floor. They are visible on <3GHz, but really shows as soon as the instrument switches to 3GHz and above. They are not stable dance around on the spectrum analyzer though the carrier signal is stable. I'll link to a video below:?
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https://youtu.be/TcHVk-WHKps?si=PK1RgEfZCQklWx1z
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There are also a few CAL errors on startup. It's random which one shows, but it's commonly the first one:?
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1,078,311 COAX DSC
3,503,311 (Turn to conditions not covered by diagnostics)
3,504,311 FRAC-N
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As of now, I have not done much troubleshooting. I just pulled a few of the cards and looked for obvious issues (caps, burned traces etc.). I intend to go through the power supply as I have read of issues there, particularly bad caps, causing signal problems.?
Now for the good news: I have a fully functioning 8665B which I can swap cards with for testing if necessary though it would be nice to minimize this if possible. If anyone has suggestions I'm all ears. These are not the easiest units to work on, and there isn't much in the way of documentation or info out there on them.?
Pete?
W4PJB
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