Tech Help lost 5v on DE CPU

MES

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Working on a DE WWF machine. Had the CPU out for about a year and now I am trying to get it to boot. Here is the break down.

1. Turn on power PIA and 5v leds light and stay lit, blanking never lights.
2. I get the start up phrase. "Welcome to wwf blah blah blah".
3. Display is blank. Got a little garbled garbage at first, but now nothing.
4. I have replaced the PSB and the CPU boards with working ones and switched the game eprom for the cpu board, still having all the same problems.
5. I get 4.98v on the PSB, but 4.88 on the CPU.
6. Unplugged everything on the PSB except power coming in and CN6 which goes to the CPU board. Unplugged everyting on the CPU board except CN17 which is for the 5v.
7 I am still getting the same led lights, and 4.88v on the CPU board.

Should I be suspecting the connector CN6 on the PSB and or the connector on the CPU board at CN17? Anything else I could have missed?

Board work just isn't my thing. Thanks for any suggestions.
 
If you have 5v at the ps and only 4.88 on the cpu, you definately have a connector problem. I don't believe that 4.88 will be enough to run it.
 
4.88v isn't all that low, but perhaps...

You clearly aren't getting a display - is the game coming up otherwise? Seems unlikely that two different PSU and CPU boards would both be bad.

May be a display-related issue, and if you've had the CPU board out for a year, the game may be coming up in audit mode (I'm assuming the batteries were removed). If you use the switches in the coin door, do you get any sound from the speakers? If so, it sounds like the game is up - you just have display issues.
 
4.88v isn't all that low, but perhaps...

You clearly aren't getting a display - is the game coming up otherwise? Seems unlikely that two different PSU and CPU boards would both be bad.

May be a display-related issue, and if you've had the CPU board out for a year, the game may be coming up in audit mode (I'm assuming the batteries were removed). If you use the switches in the coin door, do you get any sound from the speakers? If so, it sounds like the game is up - you just have display issues.

PSB and CPU came from a working game with no issues. Game showing same problems with good boards, so I am leaning towards a connector issue. New (working) CPU board has batteries installed. Switches in the coin door are not functioning. No sound and obviously no action on the display when they are pressed.

I think I will replace the IDC connector for the CPU board with a new molex pin type one. Maybe not being plugged in for all that time led to a build up inside the connector. Will post back tomorrow to let you all know if it helped. This game is driving me nuts!

Thanks for the replies and suggestions.
 
After many hours trying to figure this out and putting on new connectors, I had a thought. Could it be that simple? I had put the CPU eprom in the wrong socket! Switched sockets and it started to come to life, then something popped and there was a burning smell. The DMD had started to work, but now is blank as night. The good thing is the CPU has booted up correctly and the coin door diagnostic switches work, just can't see what is going on with the screen dead. Sound and lights are also fine.

The big question is, what would be your next move be in trying to fix the display?
I have already put the old display eprom in thinking the chip was toast but not luck. Also switched out the ribbon cable just in case, but nothing. Never could see what popped and burned up. No obvious signs of destruction. Fuses seem fine and all connectors to the display seem okay.

I have other displays I could put in, but I don't want to toast one of those not knowing what the problem is with this display.

Any thoughts?
 
Pop on the CPU was due to a tip transistor that blew. It blew on two boards, also took out the pre-driver(s) that went with it. Removed the coil that I think caused it, will report back after replacing the coil (it was toast). The display problem seems to be on the controller board. If the cable from the CPU is disconnected the game boots and goes about it's business. Sounds are good, LED lights on the CPU are good, GI are good, attract sounds good too, switches for the diagnostics seem to work, just the display seems bad. Going to try to get it to work without the coil. Also just replaced the connector from the PSB to the display control board on both ends. Just about ready to call in the experts. Will report back.

PS the board when I got it was toast for the coil location on the CPU. Burned right thru the board, pin and connector. Don't think they ever even noticed the diverter not working. I never thought to look at the coil. Thought it was a connector issue.

Wish me luck.
 
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