Help with CTM644 Monitor

[RetroAsh1978]

Hello everyone. I was wondering if someone could assist please.

I have bought a very nice condition CTM644 and being working for a few days and now its just shows a horizontal bright line when I turn on my Amstrad, nothing when off. This happened out of the blue with no noises or warning.

I read this could be vertical collapse. I do have a spare working CMT644 mainboard which I could swap but I would like to try and fix it.

Any help would be appreciated as it was a beautiful picture.

CTM644

Mainboard

Thankyou

[Bryce]

Hi,
    it's highly likely that one or more electrolytic capacitors decided to "retire". I would recommend you (or someone who knows how to if you don't) to replace the those caps. It's quite a bit of work to remove the main PCB, so you may as well replace them all while the board is out.

Bryce.