68kMLA Classic Interface

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Another Dead Color Classic - No power on, before and after cap replacement.

Posted by: Classic_II on 2019-12-08 21:15:38 Hey Guys, I have a color classic that has worked great though the years. Tried to turn it on this week and got nothing... I guess the caps finally went.  Opened it up and had a little leakage, cleaned up with Isopropyl and ordered some caps from console5. Caps arrive and I replaced them but it still doesn't power on 🙁 I started reading all the previous posts here and started checking voltages and traces. What I found out was, the system WILL power up when the board is removed. As soon as I plug in the board the system immediately shuts off.  I checked the Analog Board Voltage and have a good 5v and 11.95v. After messing around I was able to get the board to go in and the system stayed on, but i only got a black screen with horizontal lines. After I took the board back out and inspected it I found the Ti 9307XN Chip in the upper right corner by the 2 100 and 47 caps was very HOT!!! Checked the traces around it and could not find anything off. Maybe this is the problem ? I am hoping you guys can help 🙂

Posted by: bibilit on 2019-12-09 00:23:37 Capacitor shorted somewhere ?

Posted by: Classic_II on 2019-12-10 07:39:44 I removed all the caps and re soldered them, no change.  I removed the cap right next to the chip and it no longer gets hot. But still have no clue what the issue could be.

Posted by: bibilit on 2019-12-10 07:52:13 Can be the Egret chip being contaminated, happened to me more than often. IIRC there is also a capacitor next to it and battery holder. View attachment 8746

Posted by: elemenoh on 2019-12-12 15:09:38 Try cleaning underneath the egret chip and replacing the crystal next to it.

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