Tech: MM garbled ColorDMD display

[pinsanity]

Looking for some assistance on this please.

Yesterday I changed over all my globes to LEDs and machine appeared to be working fine (no display problems).

Booted up my my MM today to find this problem.



Through swapping parts back and forth with my AFM I have concluded the following as working correctly:

1. The ColorDMD display itself.
2. ALL ribbon cables
3. AV board
4. Power Driver board

That leaves the CPU board to check and the fact I changed all of the globes over to LED's.

So that I can eliminate/isolate the LED variable is there any reason installing LED's would cause the display to go like this? The ColorDMD runs off a 12v connector on the Power driver board with the ribbon cable itself attached as per normal to the AV board so there is really no correlation with the LED's as far as I can see but I am certainly no tech expert?

If it is not the led's causing this where do I start looking on the CPU board?


It is only the display itself - I can still hear and cycle through and operate the test menu (although I cannot see it) and I can still start and play a game as per normal (but with a garbled display).

Thanks for any advice.

[studley67]

where did you install leds?I have seen machines with the gi wires installed back to front.not sure how this would affect the display though.

[pinsanity]

The entire machine has been LED (flashers, gi, inserts, backbox) so not all that keen on removing them all again. 

I can't see how it relates to the display either but I haven't done anything else to the machine and it was working fine yesterday....

[Strangeways]

After changing over the LEDs initially, there was no problem until the next day. I would tackle this by ;

1 - Installing a standard display and check. I would expect it to work.
2 - Remove the factory plug for J116, and connect the ColorDMD directly to J116
3 - Remove only the LED flashers, or disable them by removing the corresponding connectors temporarily.

I'm thinking that one of the LED flashers is dragging down the +12V for the ColorDMD.

I've seen strange issues on older games with some 906 and 89 flashers on the market.

[pinsanity]

Pulled the CPU out of the machine today.

Reseated EVERYTHING that could be practically reseated (including ROMS and socketed U20 just for the hell of it).

Plugged it all back in and problem solved; we are back in business.  

Just as an aside the CPU indicated no bootup problems via the red LED CPU lights prior to removal from the pin - so never trust a machine....

Cheers for the tech help.