Hello to the forum,
My HP8566B has developed a problem where the trace when looking at a signal (either externally applied or from the 100 MHz CAL port) is noticeably wobbly at spans below 100 MHz. At a span of 5 MHz or below the trace is a broad mess. It looks like one of the LOs has come unlocked. Any ideas on which one? How to check? I have used 8566s at work and home for many years but never had to repair one, so any thoughts would be appreciated.
73 Dave W2KV