Fish Tales DMD Dead

[RGV]

As per the title the DMD on my Fish Tales has stopped working.

After opening the backbox to adjust the power/ CPU data ribbon to fix a solenoid issue, the DMD worked fine (as did the solenoids in question), but the next time I switched the pin on the DMD was completely dead.

I've swapped in another DMD which was equally non-responsive and I've also swapped out the F601 & F602 fuses on the DMD board (F602 was black so I initially assumed that was the issue. F601 was 3A instead of 3/8A so that got swapped out as well, just to be safe), however still no joy.

I'm pretty sure its not the data ribbon to the DMD from the board (J603) as I've got one of DrPinballs Apron extender displays installed and thats still running fine. I've swapped the data ribbon running from the extender board to the main DMD just in case, but again no luck.

Finally I've reseated the J604 & J606 power connectors on the DMD board and the power connector at the DMD itself with no success (none of them seem to have loose wire connections or burn marks suggesting issues either).

Writing this up I realise I might not have tried re-seating the J605 power connector so I'll try that when I get home, but assuming that yields no result does anyone have any further suggestions?

 

[Moonraker]

Grab a meter and measure the voltages on the display pcb connector....?

http://www.pinwiki.com/wiki/index.php?title=Williams_WPC#Testing_DMD_Controller_Power

 

[pinballmania]

What Peter said. I bet you don't get 62v where you should do.

 

[Spandangler]

Seems odd that it happened after reseating the ribbon cable.
I recall on my FT I reseated that cable to try and stop resets. Afterwards I had no dmd, certain coils and GI out. I just kept reseating it about 10 times and eventually everything came back. have you tried using a mother ribbon cable from a different game?

 

[RGV]

What Peter said. I bet you don't get 62v where you should do.

Spot on - Other pins are as expected (within variance) but Pin 8 barely even registers a trickle (<1V).

I presume its a board fault somewhere then?

 

[pinballmania]

Indeed. Often it's one of the 4 47k resistors gone open. Can be other stuff too. Measure them with a meter. But lift a leg of each of the large capacitors first otherwise you'll get strange readings. Discharge the caps before doing anything.