Not a very major repair, but certainly, noteworthy. I have a 8565A here on the bench, and actually use it quite a lot, along with the 8569B, because it saves you a lot of time not to have to wonder about all the buttons and switches of more sophisticated analyzers. Also, for its coverage (up to 22 GHz with no external mixers), it is rather affordable, and should it suffer from accidental abuse, which can always happen on a test bench with so many cables, it is rather easy to fix because of parts units being available, and because of its discrete construction. Needless to mention, full schematics are available from the HP service manuals.
The only downside of the unit, the CRT – it is working just fine, for all practical purposes, but has some ‘slow’ sections in the variable persistance and storage modes. These show up as green spots in the baseline region. Over time, you can make them disappear, but it takes multiple erase cycles, quite a tedious procedure. For the most part, I just did not care about these spots.
Fortunately enough, I was able to get hold of a spare 5083-4471 CRT, which has been sitting in the storage room for quite a while. Condition was said to be ‘essentially new’ but never checked.
Last week, finally decided to give it a try, risking to have to install the old CRT again, in case the new one doesn’t turn out to be so new.
You be the judge…. conventional mode
… stored display …
… variable persistence mode …
…. good as new.