Flaky Colecovision - any advice

[Tom]

Hello,

 

I've got a Colecovision which behaves odd:

The AV-output delivers the video signal, but sound consists of noise only.

When the thing is powered on it often doesn't come up (video is noise aswell), hitting the reset switch (sometimes more than once) brings the system up. First I thought it's the cartridge connector, but the same thing happens also without a cartridge inserted (the "turn off before inserting cart" screen should show up then).

 

I know how to solder and the Coleco isn't exactly something I wouldn't touch, but I'm no good at finding faults in electronic circuits. Has anybody ever had a Coleco with similar problems and knows what it could be?

 

Cheers

Thomas

[GonzoCV-1]

The Coleco's pretty sensitive to power issues.

 

Clean or replace the main power switch, desolder the 4 wires coming to the main board, snip off a little on each and resolder to avoid corrosion losses there, then "tin" the prongs of the power connector for starters.

 

Beyond that, electrolytic capacitors are the most likely "failure" parts after long periods of time (ceramic caps will fail in the first couple years if at all, otherwise they last damn near forever); so, you may want to try replacing the caps on the board -- start with C16 which ties to the power for the sound chip.

 

Good luck!