(Topic ID: 273376)

Bally as-2518-17 mpu issue

By Theonlylilo

3 years ago



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#5 3 years ago

To be clear, using Leon's ROM, when you install the 5101, the program locks up. Right?

I would check for a solder bridge created when replacing the 22 pin 5101 socket.
The easiest way to check is...
1. Set meter to continuity.
2. Black on pin 1.
3. "rake" pins 2 - 22 with the red probe. There should be no "chirps" of continuity.
4. Move Black to pin 2.
5. "rake" pins 3 - 22 with the red probe. Again...no chirps.

Continue this process until you are only testing between pins 22 - 21.
Some pins might chirp, like pins 11 and 12 are tied together by the PCB traces.
Compare your results to the schematics.
Happy hunting.
--
Chris Hibler - CARGPB #31
http://www.ChrisHiblerPinball.com/Contact ... for board repairs
http://www.PinWiki.com - The Place to go for Pinball Repair Info

#8 3 years ago
Quoted from Theonlylilo:

I have to change hobby

Nahh. You'll get it. Keep pluggin'.
I see that you had to rebuild traces above/around U11. I'd review that work closely to ensure none of the traces that run between pins aren't shorted to those pins. Your meter on continuity check is the best tool. Somewhere, you will find a shorted or an open trace.

Also, Leon's ROM should be exercising all of the data/address lines at the 5101. A logic probe should show all of them pulsing consistently.

We look forward to your impending victory!
--
Chris Hibler - CARGPB #31
http://www.ChrisHiblerPinball.com/Contact ... for board repairs
http://www.PinWiki.com - The Place to go for Pinball Repair Info

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