Whew. Just recovered from what seemed like a total disaster, and it turned out the culprit was the analog board connector, and notably also those metal tabs holding the analog board to the ground shield not being perfectly straightened. Well probably - I need to test it some more.
Short story long, this CC has extremely good picture but had problems with the 5/12V voltages being too low, so the computer sometimes wouldn't boot. No much surprise, this was due to some of the larger capacitors around the low voltage transformer leaking pretty badly. They leaked to the other side of the board even, causing decay of the solder mask and even some copper underneath. Lots of cleanup there, reapplying the mask, reflowing some decayed solder points, and after I've replaced all the larger capacitors (those recommended by Brachus Creations) I've tested the board to make sure it's still working - and it did! It worked perfectly in fact, and I was getting correct 5/12V voltages.
So with the worst behind me I got the board out again and replaced all the remaining 30 or so smaller caps. Nothing of note happened here, I double and triple-checked orientations and values of all the caps, installed the board back in and...
It all went wrong.
- With the Mystic logic board installed, computer powered up when I pressed the keyboard button, it played the chime but the screen never came on.
- With the original CC logic board, computer powered on as soon as I flipped the switch on the back, and it either played no chime, or it played some scratchy noise through the speaker. Screen never powered on.
- One subsequent powerup with Mystic board produced a bit too loud and weird sounding high voltage hiss, and another time computer booted but the picture was half the size it should be.
As you can imagine seeing all these random problems freaked me out a bit, so I pulled the board out, checked it over again, cleaned it again with some alcohol and soft toothbrush. Re-inserted it - and it worked! - once. Next bootup was again back to screechy speaker sound and no image. Eventually I realized that this may all be happening because the two metal tabs holding the analog board to the ground shield are slightly bent in such a way that they are pushing against the front case plastic, and angling the board out ever so slightly, and the connector was acting up.
So before you start to despair when the AB recap goes wrong, make sure you straighten out those two tabs perfectly, and insert the board in firmly - and once it works, don't touch it anymore
I really wish there were some locking tabs/screws between the case and the AB, but I guess when the back case is screwed back on, it does push the board in firmly - at least I hope it does.
Make sure the vertical portion of these metal tabs is not bent outwards:
Short story long, this CC has extremely good picture but had problems with the 5/12V voltages being too low, so the computer sometimes wouldn't boot. No much surprise, this was due to some of the larger capacitors around the low voltage transformer leaking pretty badly. They leaked to the other side of the board even, causing decay of the solder mask and even some copper underneath. Lots of cleanup there, reapplying the mask, reflowing some decayed solder points, and after I've replaced all the larger capacitors (those recommended by Brachus Creations) I've tested the board to make sure it's still working - and it did! It worked perfectly in fact, and I was getting correct 5/12V voltages.
So with the worst behind me I got the board out again and replaced all the remaining 30 or so smaller caps. Nothing of note happened here, I double and triple-checked orientations and values of all the caps, installed the board back in and...
It all went wrong.
- With the Mystic logic board installed, computer powered up when I pressed the keyboard button, it played the chime but the screen never came on.
- With the original CC logic board, computer powered on as soon as I flipped the switch on the back, and it either played no chime, or it played some scratchy noise through the speaker. Screen never powered on.
- One subsequent powerup with Mystic board produced a bit too loud and weird sounding high voltage hiss, and another time computer booted but the picture was half the size it should be.
As you can imagine seeing all these random problems freaked me out a bit, so I pulled the board out, checked it over again, cleaned it again with some alcohol and soft toothbrush. Re-inserted it - and it worked! - once. Next bootup was again back to screechy speaker sound and no image. Eventually I realized that this may all be happening because the two metal tabs holding the analog board to the ground shield are slightly bent in such a way that they are pushing against the front case plastic, and angling the board out ever so slightly, and the connector was acting up.
So before you start to despair when the AB recap goes wrong, make sure you straighten out those two tabs perfectly, and insert the board in firmly - and once it works, don't touch it anymore
I really wish there were some locking tabs/screws between the case and the AB, but I guess when the back case is screwed back on, it does push the board in firmly - at least I hope it does.Make sure the vertical portion of these metal tabs is not bent outwards:
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