A couple of years ago I won a HP 8131A 500MHz Pulse Generator from a PP auction. Unfortunately it turned out to be faulty, I've done some work on it but had enough of it now plus I need to clear some space. To be honest even if I fix it I don't really need it.
New mains filter
CPU board tested good
PSU tested good
Output board fault diagnosed and repaired.
Unfortunately it still comes up with an E304 error, which I
think relates to the timing board as I tested the output board in a good unit and there were no errors. There's a lot of custom IC's in the timing board and it could well be one of those at fault.
It cost me around £180 I seem to remember, plus a new schaffner filter and lots of diag time. I've currently got it on ebay for £80 trying to claw at least
some money back on it.
It's too big and heavy for me to want to ship it, so collection preferred. If it's not too far may deliver or meet you somewhere.
ebay listing here
https://www.ebay.co.uk/itm/116108108225