monitor multicolored vertical lines

[grasswire]

everything was working fine on old PC. Plugged headphones into appropriate spot, and monitor screen went black. Rebooted, and multicolored vertical lines appeared immediately. Can't think of anything to try. Can't go to safe mode, nuttin'.

Any ideas?

Thanks in advance.

[discntnt_irny_srcsm]

1. Desktop, laptop?

Headphones:
Standard 3.5 mm -

USB -

[grasswire]

3. desktop, standard 3.5

I don't know if that plugging in had anything to do with monitor trouble.

[discntnt_irny_srcsm]

5. Have you used the 3.5 jack...

...to which you're referring, prior to observing the monitor issue(s) you're asking about?

If not there may be a short of some kind with the connection to that front panel jack.
Does the monitor work when connected to a different computer?

If you have used that front panel jack before, have you had that computer serviced recently?

[grasswire]

6. The power source was recently replaced.

Prior to that, the combo of the computer, monitor, and headphones worked just swell.

This is the first time I have plugged in the headphones since the power source was replaced.

I haven't tried the monitor with a different computer, and that would not be easy to do.

[discntnt_irny_srcsm]

7. While replacing the power supply...

...the tech may have had to disconnect the front panel cables for clearance to remove the supply. Many motherboards have those sections close to where the P/S would be located. I'd guess the tech made the reconnection improperly. I'd say you have a case for asking the same shop to correct the problem.

Hopefully the damage is limited. You should unplug everything until it's serviced.

[lastlib]

2. CRT or flat-screen?

Does the monitor have a self-test function? (It won't be on the computer itself, it'll be the monitor controls.) This sounds like a classic case of a CRT-style monitor dying. You can try fiddling with the monitor controls, but I don't think you'll have much luck.

[grasswire]

4. not a flat screen

an old reliable HP Pavilion.

A dinosaur, but important to me.