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General Category => Technical support - Hardware related => Topic started by: RetroAsh1978 on 17:26, 16 May 24

Title: Help with CTM644 Monitor
Post by: RetroAsh1978 on 17:26, 16 May 24
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 (https://www.dropbox.com/scl/fi/s414f9ki4q1503wp1q6zn/Photo-16-05-2024-5-18-03-PM.jpg?rlkey=mov5pzpux3s3ytwvqady657f1&dl=0)

Mainboard (https://www.dropbox.com/scl/fi/s5s86p6nzctiw0jg8g184/Photo-16-05-2024-5-18-16-PM.jpg?rlkey=i3nhz5j84paxtj38mi52oh6nq&dl=0)

Thankyou
Title: Re: Help with CTM644 Monitor
Post by: Bryce on 13:51, 18 May 24
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.
Title: Re: Help with CTM644 Monitor
Post by: roy bates on 11:24, 27 November 24
that is vertical collapse

its either no power to the vertical section,or ,vertical ic failed(most common)
if its capacitor,its shorted and probably took out the power rail before it,thats from experience

this is comming from someone who repairs monitors and tv's for the last 35 years

and yes,i have worked on these and still do
Title: Re: Help with CTM644 Monitor
Post by: martins on 15:09, 27 November 24
Thanks Roy - from your experience, on a working monitor, is it worth replacing any/all of the caps to prevent future damage, or only worth doing when one of them fails?
Title: Re: Help with CTM644 Monitor
Post by: roy bates on 16:46, 27 November 24
thats up to you,i dont usually unless they are bad during a repair
Title: Re: Help with CTM644 Monitor
Post by: martins on 18:06, 27 November 24
Thanks very much
Title: Re: Help with CTM644 Monitor
Post by: darkhalf on 04:56, 01 December 24
I've had to fix up a couple of mine, and all the ESRs on the caps measured fine. So I would personally only replace what is needed. 

Check the capacitors in question for shorts first. If the power section is gone, the components it takes out can very (see my other posts on here about CTMs)
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