Amstrad CPC664 Keyboard Issue.

csb1980 · 19:59, 12 June 19

Evening Folks,

A rather random one here that I hope someone can help with. When I turn on my 664, after approx 30-40 seconds, text just starts randomly appearing across the screen as if the keyboard were being randomly pressed, but it isn't being touched at all! Was working absolutely fine up until a few days ago and now this happens every single time with out fail.

Any thoughts on how to rectify?

Regards

Colin.

Token · 22:51, 12 June 19

Hi, maybe the AY is faulty. I had this kind of problem on a 6128 and added a socket as well.

Bryce · 07:06, 13 June 19

Clean the keyboard membrane first. If the problem persists, it's probably the AY.

Bryce.

csb1980 · 01:02, 17 June 19

Hey guys, thanks for the info. Tried cleaning the membrane, the contacts where black, did the trick for a very short while but the problem is back again. Very keen to get this sorted. Could you possibly explain a bit more about the AY and what would be required to resolve.

Many Thanks

Colin.

Duke · 06:30, 17 June 19

Try disconnecting the keyboard and let it run without it attached.
If the problem is gone it is the membrane, otherwise most likely the AY.

Quote from: csb1980 on 01:02, 17 June 19
Hey guys, thanks for the info. Tried cleaning the membrane, the contacts where black, did the trick for a very short while but the problem is back again. Very keen to get this sorted. Could you possibly explain a bit more about the AY and what would be required to resolve.

Bryce · 07:32, 17 June 19

If cleaning helped for a bit, then the AY is fine. I also just realised that we're talking about a 664 here. They are known to have flakey membranes, so order a new membrane from RWAP over on sellmyretro and swap it out.

Bryce.

csb1980 · 08:28, 18 June 19

Morning Folks,

So as you can see from the attached picture, sadly the same thing is happening even with the keyboard section completely removed. The text starts to display approx 1 min 30 secs after witching on and tends to always be the same. Also the when it gets to the point you can see on the screen the speaker starts ringing constantly as if a key is stuck down.

Colin.

Bryce · 09:43, 18 June 19

Ok, the AY (sound chip) is most likely bad.

Bryce.

csb1980 · 14:58, 18 June 19

Ok, so how we do go about replacing the AY chip? Or even better, anyone here offer any repair services or know of someone who does?

Thanks

Colin.

Bryce · 07:19, 19 June 19

Replacing the chip involves carefully removing the old one, like this: http://www.cpcwiki.eu/index.php/IC_Repair then installing a socket and a new AY.

If you don't think that this is something you can do, then you can send me the PCB and I will swap it for you. Send me a PM for details.

Bryce.

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Amstrad CPC664 Keyboard Issue.