Author Topic: CPC 464 - Blank screen  (Read 1191 times)

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Offline MrLee

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CPC 464 - Blank screen
« on: 18:57, 15 November 20 »
Evening all,

I recently got hold of a CPC 464 (Z70100 board) with a CTM 640 for a trip down memory lane. It was listed online as working and when it finally arrived, despite looking a bit dusty and faded it did appear to work. Sort of.


When I plugged it all in and turned it on. It booted to the ready screen fine. Only there was no colour blue? After a bit of fiddling with the wires I found that the video connection was a tad sketchy and the colours would jump in and out as I wiggled it. I assumed the pins/board needed a clean so unhooked it all and carefully stripped it down. I cleaned out all the dust and accumulated fluff from the board, cleaned the pins on the video cable and gave the solders a quick once over. Bear in mind I've never held a soldering iron in my life so wasn't sure what I was looking for but nothing jumped out at me as obviously out of place. I Put it all back together and left it for a bit.


Later I plugged it all in again. Turned it on and got a blank screen. No amount of wiggling of the cable did anything at all. The power LED is on and it beeps when I press Del, so I'm assuming that I've done something to the port while cleaning it. I stripped it down again but couldn't see anything wrong. And that brings me here.

I'm now at a bit of a loss. If it is said port, is that something which could be replaced without much difficulty? Or are there other things I should perhaps rule out first?
Thanks

Offline Bryce

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Re: CPC 464 - Blank screen
« Reply #1 on: 20:05, 15 November 20 »
Hi and welcome,
         my first guess would be that the wiggling disconnected the remaining strands of wire in the cable, not only on blue, but sync aswell. If you have a suitable TV (with RGB SCART), I'd suggest you buy an RGB cable to confirm the CPC isn't the issue (unlikely, and it's a useful cable to have). The CPC is most likely fine.

Bryce. 

Offline MrLee

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Re: CPC 464 - Blank screen
« Reply #2 on: 10:58, 16 November 20 »
Hi Bryce,


Thanks for the quick reply and the welcome. Following your advice I've got a powered RGB scart and a 464 power supply on its way and ill give em a try on one of my old TV's i got kicking around once they arrive and go from there.


Cheers

Offline MrLee

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Re: CPC 464 - Blank screen
« Reply #3 on: 11:28, 20 November 20 »
Update

Seems you were spot on Bryce, image is crystal clear through the new RGB SCART and all the colours are present. Time to do a spot of surgery on the monitor connector now and hopefully get it all sorted.


Offline Bryce

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Re: CPC 464 - Blank screen
« Reply #4 on: 13:15, 20 November 20 »
If you want to keep it looking original, I probably have a spare replacement cable here (original cable taken from non-repairable CTM). The cable plugs directly into the CTM PCB, so no soldering is required (just lots of caution as the PCB can give you a fatal shock if you touch the wrong part). Let me know if you want one and I will check that all connections are good on the one's I have here.

Bryce.

Offline MrLee

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Re: CPC 464 - Blank screen
« Reply #5 on: 17:05, 07 December 20 »
Update #2

Works been a bit mental so I had to put the 464 on the back burner for a bit. However yesterday I took it to my brothers (Who's more experienced with electronics than myself) and we re-soldered and re-glued the connector. Still no signal so next I'm going to check the other end and see how that's looking. Ill have to get back to you about the spare cable and see how I get on with the current one, Thanks for the offer though.

Also I'll make sure to be careful with the PCB :)

Offline MrLee

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Re: CPC 464 - Blank screen
« Reply #6 on: 23:09, 07 December 20 »
Fixed!

I dug out the marigolds and had a look at the CTM 640 PCB, turns out the wires in the connector on the actual board side had slipped out of their holes. The tiny clips that kept them from being pulled out were completely flat. I bent them back out a bit, made sure they were all re-seated correctly, gave the insides the once over with a can of compressed air and removed a mummified fly before putting it all back together. Works perfectly!

Thanks for the advice Bryce, now my only problem is the Mrs wont let me play it till Christmas as it was a present.

Offline Bryce

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Re: CPC 464 - Blank screen
« Reply #7 on: 10:25, 08 December 20 »
Congratulations. At least you know that you CAN use it over Christmas.

Bryce.