Question about display issue in HP 8590A Spectrum analyzer

[Johnny10]

I have been storing my HP8590A for about 4 months in a clean dry non-airconditioned space.

Turning it on yesterday I was greeted with the first screen below. (screen is stable in this distortion not flickering)
After a 2 hour turn-on time my screen was back to normal.

This morning 12 hours later screen is again stable.

What could be the issue?

[bob91343]

Looks like a fault in the vertical amplifier.  Perhaps a bad connection.  I would open it and poke around with a screwdriver handle and see if I can make the problem come and go.  Wiggle all the connectors.

[m k]

Is it interlaced with dispositioned frames?

[T3sl4co1l]

Guessing dry electrolytics in the CRT circuit.  Recap it.

Or replace the module wholesale, it's a somewhat standard display module -- or it was at the time, don't know how cheap/available spares are now.  I think some have even built LCD conversions, though the resolution is very nonstandard so it's a nontrivial process.

Tim

[MarkL]

There are different model monitors that HP used in the 859x series, but they should all have a vertical hold adjustment somewhere.  At least one model has it accessible through a hole in the top of CRT case and I think is marked.

Before doing anything drastic, I would try to find that pot first and give it a tap or a slight turn.  If no joy, you could also try doing the same thing to the vertical height adjustment.