I have read the Coleco repair pages here:
http://www.handheldmuseum.com/Coleco/ColecoRepair/index.html
But I have a question to you electronic wizkids out here.
The unit I bought does not power on.
This is what I checked:
- I have a Gakken unit (which has a power plug instead of the Coleco branded ones), so I connected 6V mini-mini jack (2.5mm, 6.3 V tip).
- When the switch is off, I measure +6.3V between the red wire-solder point on the PCB and the black one (seems totally logical).
- When the switch is on, I measure +1.5V on the switched pin from the on/off switch. That feels weird, I think it should still be 6.3V.
What can this mean?
From the site:
"If power is getting to the main board, and seems to be getting through the power switch, but doesn't go much further, I'd suspect a transistor. For me, this is a quick test, but if you aren't familiar with de-soldering or testing transistors, then this might not be for you. Basically, there are two transistors in the game (one circled in yellow, the other is the black square right below it), remove them both and test them with a meter. (Other games might have more, just learn their apperance, they are black, almost always circular with one flat face, and have 3 connections coming out of them.) If either fails, replace it. (They are cheap, you can always just replace them instead of testing them if you'd rather go that route.) I'm still surprised how many games I've fixed with this one procedure. It just takes plugging in the wrong kind of power once... These almost act like fuses for the game.
If none of the above seems to fix the game, and things aren't getting hot when turned on, try testing several points on the game with the volt meter and see if you can trace how far power is going. Also, check the traces on the main board as best you can for damage, corrosion or breaks (see the section below about my problem for an example of this). If you are determined to fix your game, remove all the transistors, resistors, diodes and capacitors, and test them all. If everything is working, and you can't find physical damage to the board, most likely the CPU chip itself got damaged. That usually means find another game... (Also, if you find a bad component, test them ALL before you replace the one and power up the game. Another component could be causing the damage to the one you just replaced.)"
Try to check the transormer too!!
