Afternoon all!
I've had this HP 3585A for a few weeks now and it's been working great. Tonight I noticed that the CRT is, for lack of a better term, twitching. I took a video and you can see it more clearly once I turn down the CRT intensity later in the video. Also note the reference line is not as pure as it once was. It's almost striped looking now.
Any idea what could be causing this? I would assume a power supply issue.