HELP: Stern MPU-100 for a Stern Dracula

qbass187

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Hey guys,
I have a 79' Stern Dracula pin that's been sitting forever and every once in a while I try to get it working....
At this point I've replaced the Solenoid driver, the power supply and swapped out the MPU and all I get is lights and flippers.
I was thinking it might be the ROMs in the MPU-100 because I've replaced the one that was in it (swapping ROMs back and forth)band nothing changed.
I keep coming back to the MPU as the problem but I can't figure out why...

Anyone have any experience with these???

Any help would be greatly appreciated.
Thanks, ERIC
 
If you're getting the flippers to work, the game is booting up since the flippers aren't engaged until a game is started.

Bad connectors, bad fuse clips, burned connectors on the transformer block are all notoriously bad for the early Bally and Stern games.
 
From what I understand, the flippers are engaged by the MPU engaging the Solenoid driver relay?

Normally the MPU will energize the flipper relay when you start a game. That's true.

But... if there were a PIA problem the flipper relay could still be energized even with the MPU not booting. In fact there could be a bunch of different problems causing the flipper relay to energize.

What we really need to know is how many flashes are seen on the MPU when you turn the game on.
 
MPU board

One thing to check is your replacement mpu board. You can replace MPU 100 with an MPU 200 but it needs to be jumpered correctly to run mpu 100 roms. Not sure what your replacement is but a heads up.
 
How many flashes (if any) is the MPU showing? Any corrosion damage?

No flashes at all...just a steady red LED
There's no corrosion damage at all, the MPU was rebuilt buy TWO BITS before I owned it and they replaced it with a lithium type battery.
The MPU, Solinoid driver and Power supply were all rebuilt.
 
One thing to check is your replacement mpu board. You can replace MPU 100 with an MPU 200 but it needs to be jumpered correctly to run mpu 100 roms. Not sure what your replacement is but a heads up.

I didn't replace the MPU 100, what I did was I borrowed another one tranfered the ROM chips and dip switch settings and installed it to see if my MPU was the problem and there was no change when I swaped the 2 MPUs out.
 
BTW, when I went to turn it on today the flippers didn't engage anymore...they did before.
All I get now is a loud sound (for a second when it starts) and lights.
 
Rom Woes

I didn't replace the MPU 100, what I did was I borrowed another one tranfered the ROM chips and dip switch settings and installed it to see if my MPU was the problem and there was no change when I swaped the 2 MPUs out.

Well if you have access to another pin you can install the mpu/roms in it and see if it boots. Can ensure your roms are good that way. I ended up buying one of the altek replacement for my cheetah, though my board was toasted from battery damage, just program your roms .
 
No flashes at all...just a steady red LED
There's no corrosion damage at all, the MPU was rebuilt buy TWO BITS before I owned it and they replaced it with a lithium type battery.
The MPU, Solinoid driver and Power supply were all rebuilt.

A solid LED could be a number of problems. Read through this:

http://pinrepair.com/bally/index2.htm#flash

I would start by checking the voltages at the test points on the MPU. Then I would pull the MPU out of the game and test it with a switching power supply starting with the reset and clock circuits and going from there.
 
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