68kMLA Classic Interface

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Another Color Classic that wont power on.
Posted by: mmmlinux on 2023-03-28 21:22:19
Hello all,

I picked up a Color classic in unworking state. It has not been battery bombed but the caps definately let go. I replaced all the caps but still no go when I hit the power button on the keyboard. Did some reading on here found that the egret (cuda?) chip frequently doesnt like getting electrolyte on it. so i removed it cleaned it and the pads and put it back. Still nothing.. Got the Bomarc schematics, found a few traces that were not working from that chip. Now continuity is good to every where it should be but still no power. Any ideas? These don't need a battery to start from what I've seen correct? How likely is it that the micro is just dead now?
Posted by: bibilit on 2023-03-29 00:00:08
No battery required.
Posted by: imactheknife on 2023-03-29 15:58:29
could be analog board as well. Color classics can be picky. Clean the contacts on edge of logic board with eraser or isopropyl on both sides. I would even recommend a total isopropyl bath and light scrub over everything with tooth brush and let dry.
Posted by: jajan547 on 2023-03-29 19:53:18
Color Classics are odd machines I've had a few do the same thing. If you leave the rear switch turned on and the machine plugged in for say 15-20 minutes turn it off then turn the switch back on and hit the keyboard power button.
Posted by: mmmlinux on 2023-03-29 20:27:06
Can anyone confirm that pin 16 of U7(CUDA) connects to pin 16 of U16? This is shown on the bomarc schematic but ive already found errors on this page. and another page of the schematic says pin 16 of U16 is the A23 line.
Posted by: jajan547 on 2023-03-29 20:31:11
Can anyone confirm that pin 16 of U7(CUDA) connects to pin 16 of U16? This is shown on the bomarc schematic but ive already found errors on this page. and another page of the schematic says pin 16 of U16 is the A23 line.
Pin 16 of U16 and Cuda Pin 16 do not connect I just tested on my good board.
Posted by: mmmlinux on 2023-03-29 20:34:22
Pin 16 of U16 and Cuda Pin 16 do not connect I just tested on my good board.
Thanks for checking. That makes sense at least. but now I'm not really sure where that connects besides a resistor. Ill pull that bodge off and try leaving it with some power for a few minutes.
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