[prbs23]

This is an awesome write up!

I have one of these scopes, with exactly this issue after a long period in storage. When I was looking into it a few years ago the failure mode was known but I couldn't find a recovery procedure. I'll need to give this a try when I get a few hours. I have been putting off getting a new scope in hopes that I could repair this issue.

[salvagedcircuit]

Thanks! Go for it or contact Keysight to see if they will cover it. Good luck!