I am trying to restore a Bally Playboy that has been in storage since the early 1990's. The MPU was severely corroded so I replaced it with an Alltek Ultimate MPU. While I was at it I also replaced the SDB and lamp driver boards with Alltek units and the rectifier board with a Rottendog. I initially had an over voltage error on the MPU and finally determined (with the help of this forum!) that the J4 connector was corroded. I re-pinned the bottom five pins on J4 and the unit booted up. At that time I had sound, lights, knocker and flippers. I realized that the playfield fuse was blown. I only had a higher value fuse so I did try it briefly and determined that many of the coils worked but some did not.

I've received the proper fuse and to try to resolve the coil problems I saw earlier I decided to go ahead and re-pin the remaining connections on J4 as well as SDB P2. Unfortunately I think I've created an issue. The MPU goes through self test properly (LED flashes, etc.). The SDB shows all the correct LEDs and the cyclone is running. However I have no solenoid action except for flippers. It almost acts as if the playfield fuse is blown but it is good, and I have 38vdc to the coils. I also no longer have sound, but I do have a hum coming from the speaker.

The MPU appears to be working properly. Self test works properly except for sound and solenoids. Coin registration works. I can trigger switches on the playfield and points register. It also counts balls and ends normally. I just have no sound, no coils or knocker.

I did re-check the crimp connections on SDB P2 and it the connections appear fine. Before going through all of the connections on MPU J4 I thought it would be worthwhile to see if anyone can help direct me to the most likely issue.

This was exactly the issue. I had placed one of the pins in the wrong slot on the Molex connector of J4 on the MPU and that was the issue. Once I traced the wires by color code, found the problem and moved it to the correct slot it worked perfectly. Thanks for your suggestion!