Amstrad CM14 Monitor Fault

[P5ychoFox]

Does anyone have any suggestions as to which part could have failed? Please see a link to my video below:


Amstrad CPC 464 Plus CM14 Monitor Fault - YouTube

[CanonMan]

Does anyone have any suggestions as to which part could have failed? Please see a link to my video below:


Amstrad CPC 464 Plus CM14 Monitor Fault - YouTube

Knackered scan coils, which is unfortunate as they're securely attached to the back of the CRT

[Bryce]

Nah, more likely something in the horizontal scan circuitry. My bets are on a capacitor.

Bryce.

[Kris]

Bryce is right, check any capacitors (maybe distorted or leaky) in the horizontal circuitry...

[CanonMan]

Nah, more likely something in the horizontal scan circuitry. My bets are on a capacitor.

Bryce.

I still think it's the scan coils. The blue convergence being way out (particularly in the top left corner) gives it away.

[Bryce]

Yes, that could point to coils being damaged, but I work on likelyhood. I've never seen a CPC monitor die because of coils, but many that died because of the capacitors. It also depends on how it happened. Did the screen suddenly colapse, or is this a monitor that's been stored away for years and taken out for the first time? Has it just been sent in the post with some dodgy courier company (Which would again point at it being coils)?

Bryce.

[P5ychoFox]

I've owned this CM14 for many years and it worked fine a month ago. It was a sudden collapse. The monitor has not been damaged. I've opened it up and everything looks pristine inside, no damaged or leaky caps (of course there could still be a faulty cap).

[Bryce]

Capacitors don't necessarily have to have visible signs of failure, they can look perfect and still be crap. It could also be a transistor dying. Any signs of overheating (browned PCB) around any transistors?

Bryce.

Edit: Here's the horizontal path in the schematic. I would definitely change every capacitor along this path and I'd check the transistors. Also look for any resistors that look like they've overheated. Beware, these capacitors belong to those that can seriously hurt if you don't discharge them!