CPC464 LED on, no output

[Velociraptor]

I didn't know that desoldering ICs could damage them. Last night I got it working and then went through all the other 153s, ram and everything else I had socketed on the 464 and made sure all the chips I have worked. All but the 2 damaged RAM and the 1 damaged 153 work so it does appear that I have a nearly full set of CPC ICs.

After some contact cleaner the dk'tronics 64K and the Multiface 2 also work.

https://i.imgur.com/tIwUKcE.jpg

https://i.imgur.com/ncSFWv5.jpg

That means for my 464 I need a DDI-1, to change the ROM for a 6128 one, and to add a cassette port for the tzxduino and I'll then have it to 6128 functionality.

However it does need a very thorough clean, and I've not gone near the cassette deck yet. Back at the start of the thread you commented that someone has been in at the tape deck so I don't know how I'll get on with that. I have spare belts, and thankfully the main belt has not melted. I replaced the belt on the 6128 the other night and it had basically turned to glue, it took a lot of IPA to get it clean so I'm glad I don't have that with this one.

[Velociraptor]

So on to the next problems with the 464.


There was a disconnected leaf switch and going back to what you said in your very first reply Bryce when that is closed the tape deck has power, when it is open the tape deck has no power.


It took me a lot of puzzling but I think I've had a revelation as to how it works. You said it's mounted by the play button and I can see 2 little screw holes and either of which I think it could go on to.


I could not work out how pressing play could close the switch. Then I realised that if FF and RW don't work until the switch is closed then it should normally be closed. This would mean that pressing play wouldn't work until the CPC sent some kind of override signal - this is how the CPC works if I remember right. You press play and nothing happens until the CPC wants it to happen and there may even be an audible click.


So am I correct to mount this in that position where the leaf switch is normally closed, and pressing play releases it to an open position? I'm not sure how I'll mount it, perhaps hot glue or solder.


The tape counter appears to be damaged. It looks like the button has snapped off. I think I may leave the tape counter belt off and keep the tape counter at 000, I don't recall it ever being useful.


I need to strip down the volume and power controls and clean them out. Also the keyboard to remove any dust and muck that's reached the membrane otherwise over time it will destroy it.

[Bryce]

Heat destroys chips. Whether soldering or desoldering, too much heat for too long will fry what's inside.

Yes, the leaf switch is normally closed as far as I can remember. Gluing or soldering is a bad idea, and if the contacts touch the metal frame of the player you'll have bigger problems. Can't you mount it like it originally was?

Bryce.

[Velociraptor]

Sadly not. The screw is missing and I've not managed to find any that fit. I do have one that's too small though so I'll use that to hold it exactly in place and then use hot glue on it. Worst that can happen is it doesn't work properly. Then I'll have to start randomly buying packs of small screws I suppose in the hope I get exactly the right size.

[Velociraptor]

Hot glue has it solidly in place. There's actually two holes in the metal to mount it on, one is for a black plastic tag and the other is for a screw. By putting it in in place and letting the black tab hold it I was able to use hot glue to fix it in place.


I've cleaned out the keyboard which was full of debris but thankfully there's no visible membrane damage.


I've reassembled it and....


The tape fix i did works! Tapes FF and RW when I want, but only play when the 464 wants them to play. However the pause button doesn't work.


The keyboard works perfectly.


The 464 is now fully functional!


Remaining to be done -


Fix the pause button
Fix the eject button - might not work while the tape window is missing
Sand down and polish the tape window
Clean the keys more thoroughly
Find out what happens with the little spring thing that I don't know where to refit - possibly pause and/or eject related?

[VincentGR]

My pause button doesn't work either...
Waiting for your tips after you fix it