720 blank screen

LUCKYMAN

New member
Joined
Sep 22, 2008
Messages
6,465
Reaction score
54
Location
Clifton Heights, Pennsylvania
got a untested 720 board set from a fellow klov member. Tested the boards out, turns out the top board is good. The bottom board i didnt bother testing cause i noticed things broke on the board right off the bat. The resisitor for Hsync R17 was broken in half. Also the connector J13 i replaced cause all the pins were bent up..

Repaird those two things and tested the board.. Now switcher would not go on, and LED on board did not light.

So i started looking at the board again and found capacitor C7 was broke, one of the sides was pulled out of the capacitor. Repaired that with a 1uF 50V..

Now i get switcher power light and i get voltages to the board (5.0) LED is now lit.. BUT i get a BLUE screen... Can not coin up or play or anything...

Now the CRYSTAL 32V (at Y1)in the center of the board, one leg was hanging out of the baord. I re-soldered it back in there.. ( Do you think this is bad now?? Like should i replace it??

my other question is, anything else i should check on this board that commonly "goes" on these boards that you guys know off???


Heres a pic of what i replaced so far>:

boardk.jpg
 
I know jack squat about any of it, but my boards went between Francis at ataricade and El Dorado. Mine had a missing LETA chip (an obvious problem), but they also replaced the crystal...for what it's worth. Does that make it a common issue? I don't know...just happened to be what was wrong with mine. Good luck!
 
That was it!!! changed the 32mhz crystal and now i have a FULL 100% working extra 720 board set!!


woohooo

Im excited cause this is the first board i have ever really fixed for buying it non-working and fixing it... bought it for 100.00 and put 8.00 worth of parts... ohhh yeah!!!!
 
Back
Top Bottom