Hi all
Firstly, may I introduce myself to the group - I'm a massive cpc fan and have recently stared collecting the machines again. I was directed here by someone on a Facebook Amstrad CPC group, as I have a strange fault with my cpc 464?and I'm not sure whether it's terminal or not :)
I'll be honest, I've read the message boards frequently on this forum, and it's been very useful in fixing various Amstrad niggles to date! I'm now hoping someone may have time to take a look into my specific issue in...
I'm not a particularly technical person, but am handy enough to do things like change drive belts and follow guides on cleaning various components. The other day I decided to change the tape belt on my 464. Everything went smoothly and the tapes loaded great after the service. However, I have been greeted with a new error - my sound has become very garbled. I now just have horrible white noise when sounds are triggered, and can no longer get the delete key to make a beep on the main screen.
I've done some simple fault finding, and am confident it's not the speaker or frayed wires etc. I have also found a very odd quirk - if I press and hold the 'up' cursor arrow, the sound returns to normal (until the key is unpressed). I will attach a video of this
Wondered if anyone had come across anything like this? Any advice would be hugely appreciated!
Many thanks
Matt
Couldn't attach the video due to size but can send on to someone if helpful ;D
Does the same from the audio output plug?
I did try headphones but got no sound at all. They weren't the best set to be fair, so I'll test another pair tomorrow incase it was an issue with the headphones. But I would guess there will still be no sound :(
Quote from: Hulky on 00:02, 28 March 18
I did try headphones but got no sound at all. They weren't the best set to be fair, so I'll test another pair tomorrow incase it was an issue with the headphones. But I would guess there will still be no sound :(
You may have to use (for example) amplified speakers to test the audio out - it may be very quiet.
How hard do you need to press on the up key to stop the horrible sound? It does sound like a loose connection which fixed when pressure is applied to a certain point.
I have a feeling it's not to do with the pressure applied on the keys - it is only triggered by the up cursor key, and no other key has the same effect. Also, the up cursor key triggers a beep at times on the main BASIC screen, but delete key just gives the garbled sound. And I don't have to press very hard.
I've uploaded a video to YouTube for you guys to see the fault in action. It's so strange - I've checked all connections a few times. It's like something gone wrong in the audio chip and muddled everything up.
Video here - [size=78%]https://youtu.be/WgPXCQkG2ZM (https://youtu.be/WgPXCQkG2ZM)[/size]
Thanks again!
Probably is the AY but don't take my word, wait for Bryce.
Cool, thanks for your input.
If it is that I do have a spare motherboard off a non working unit, but have never soldered before so not sure if I'd give it ago myself :-[
I'll hold on for Bryce before doing anything as you say.
Thanks again
Or you can buy a new AY, it's very cheap and repair the other cpc :-)
Hi Hulky,
open up the tape drive again, my bet is that you've trapped a wire somewhere while re-assembling the tape drive and it's now shorted to the metal of the tape drive (which is ground). My second bet would be a dying AY, but it seems a bit too much of a coincidence that it happened at excatly the same time as you were working on wires that go to the sound circuitry.
Bryce.
Thanks Bryce, I will have a look again tomorrow and check all the wires around the tape deck again.
If all looks ok I will assume AY chip. But I also thought it's a bit strange that the chip died as I changed the belt - I was very careful and didn't bang the motherboard or anything.
I appreciate all the advice guys. Fantastic group this 👌🏼
Cheers
Matt