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CPC6128 Volume low

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minwah:

--- Quote from: Kris on 11:27, 02 May 16 ---Already got this issue on mine and it was "simply" due to a defective wire on the potentiometer....but i assume that you have already check this  ;D

--- End quote ---

Yeah I tried swapping the pot/cable and no difference...

minwah:
Quick update...

I replaced all of the electrolytic capacitors - no difference unfortunately.

I did try to desolder the LA4140 while in there and put a socket in. My measley skills with solder sucker and braid couldn't get all of the pins desoldered properly though, so gave up on that. Now I know it is probably that chip at fault, I will revisit at some point...

I also noticed something else with the computer on, which is that the video picture 'twitches' (up/down) when the CPC makes sound. It is not apaprent with the volume control low, but gets more apparent as the volume is increased. Don't recall noticing this back in the day, so don't think it is normal...but having said that, I do have the volume cranked since the sound is so quiet.

Bryce:
That would suggest you have a "low resistance to earth fault" in the amplifier. Definitely something wrong there.

Bryce.

minwah:

--- Quote from: Bryce on 14:35, 05 May 16 ---That would suggest you have a "low resistance to earth fault" in the amplifier. Definitely something wrong there.

Bryce.

--- End quote ---

Thanks for your help. I will report back once I've had another look at it...

minwah:
I haven't tried fixing this yet but having played around with the CPC a little bit I have noticed more related issues. Just making a note of all of the issues here for future ref:

1. Volume from internal speaker is low.
2. Sounds from internal speaker is distored when turned more than about half way up (not speaker distortion, volume is still low).
3. Video image twitches up and down when CPC makes sound. More apparent the more the volume is turned up.
4. Pressing keys sometimes affects the sound volume (jumps up or down).
5. Sometimes 'noise' can be heard from the speaker when the CPC is not producing any sounds. When the CPC makes a sound, this noise is temporarily reduced, and then tends to come back after a few seconds.
6. Tapes via the tape input do not appear to load...nothing on-screen after 'press play on tape'. I've only tried a few tapes so will try some more to confirm.

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