I have a weird DMD problem. My DMD works fine for about 10 games then it goes all scribbly, then goes to just a few solid flat lines. There are three AA batteries on the MPU behind the backglass. When I remove one the DMD goes right back to normal, so I put the one battery back in and play another 10 or so games and it does it again. So I remove and replace the battery and it's good for another 10 games and so on. Any suggestions?? Can take pics if necessary.
Weird DMD Problem
- Thread starter quarter grabber
- Start date
movingpictures
Active Member
Luckydogg420
Member
Would batteries really be the problem? I thought they were just to save high scores.
I'd look for a loose connection if the problem is intermittent
I'd look for a loose connection if the problem is intermittent
REVOLUTION said:
Yes it's JM. I'm a newb so I don't even know where that is never mind how to do it. :?:
DRANO
Super Member
I would first try re-seating all the ribbon cables (grey ones)/ These are very easy to install incorrectly so watch the pins carefully and push them in nice and firm.
Reseating the asic chip on the cpu board could also help (large square chip on lower left board). But if you've never pulled one of these I would'nt attempt it yourself without the right tools. You can do more damage than good.
But, if the high voltage area on your DMD control board is in fact fried, it'll be on a board at the top of your backbox. The one with a ribbon cabel going to your DMD.
Look for charred/black components and you'll likley have your answer.
That's about where my knowledge ends
Good luck.
Reseating the asic chip on the cpu board could also help (large square chip on lower left board). But if you've never pulled one of these I would'nt attempt it yourself without the right tools. You can do more damage than good.
But, if the high voltage area on your DMD control board is in fact fried, it'll be on a board at the top of your backbox. The one with a ribbon cabel going to your DMD.
Look for charred/black components and you'll likley have your answer.
That's about where my knowledge ends
Good luck.
Ok, I've been reading all the posts here (and at the other place) and I have to say one thing. So far everyone (besides Drano) has told you to focus on the DMD controller, but you mention in your first post the issue goes away when you pull a battery which is located on the MPU. Now I will say that pulling a battery should have ZERO effect on this issue in that the batteries have nothing to do with the DMD or the controller. That being said, logic would dictate that the forces of pulling the battery on the MPU is re-connecting whatever contacts are having issues and fixing your DMD issue. Where the MPU sends the DMD controller PCB all of the display info via the ribbon cables, I would absolutely start with pulling each ribbon cable off and re-seating a couple of times starting at the MPU, and working your way through the game all the way over to the DMD controller. If that doesn't seem to correct the issue, I would honestly start looking for cold solder joints on the back of the MPU, as well as get a PLCC chip puller and remove and re-seat the ASIC on the MPU.
Do not rebuild any PCB at this point, there are no signs that your HV is failing.
Where this is an intermittent issue, my $$ is on either of the 3 things listed above. Do the above and report back.
D
Do not rebuild any PCB at this point, there are no signs that your HV is failing.
Where this is an intermittent issue, my $$ is on either of the 3 things listed above. Do the above and report back.
D
Menace said:Ok, I've been reading all the posts here (and at the other place) and I have to say one thing. So far everyone (besides Drano) has told you to focus on the DMD controller, but you mention in your first post the issue goes away when you pull a battery which is located on the MPU. Now I will say that pulling a battery should have ZERO effect on this issue in that the batteries have nothing to do with the DMD or the controller. That being said, logic would dictate that the forces of pulling the battery on the MPU is re-connecting whatever contacts are having issues and fixing your DMD issue. Where the MPU sends the DMD controller PCB all of the display info via the ribbon cables, I would absolutely start with pulling each ribbon cable off and re-seating a couple of times starting at the MPU, and working your way through the game all the way over to the DMD controller. If that doesn't seem to correct the issue, I would honestly start looking for cold solder joints on the back of the MPU, as well as get a PLCC chip puller and remove and re-seat the ASIC on the MPU.
Do not rebuild any PCB at this point, there are no signs that your HV is failing.
Where this is an intermittent issue, my $$ is on either of the 3 things listed above. Do the above and report back.
D
I will do this for sure when I get it back together. Right now it is in pieces because I'm clear coating the playfield. Look for a future post of mine where I ask how to put it back together.