Midway Wolf unit Bad U1 - Solved

Hey guys. I bought a midway wolf unit board about 2 months ago with pretty much mostly empty sockets. Looked like a parts board, so I took a chance and figured I could program everything missing and hope to bring it to working order. So, after programming and installing all the EPROM/PIC chips, I got a Bad U1 error with no light and no Bong sound. This is where the full diagnostic nightmare began. I pulled a lot of ICs and replaced the U1 to see why it wasn't working. Everything in red was replaced or tested good. No dice. At this point I already tested all the resistors and inductors in the entire sound circuit area. All Good. Then I tested all the capacitors last night. All good. Now, on a Whim, I took a meter and started to test pins on the bottom of the board for the heck of it. Anything that looked even remotely off. The close up photo of the pin you see ended up being my culprit. Where, you might ask? an Empty Socket (I believe it was U9). The close up shows a sliver of silver on the trace. The pin was completely bent down and flat against it. The multimeter beeped and initially I didn't know why but it was shorted. I lifted the bent pin and the short was gone. After testing the rest of the board (cause I didn't think it could do anything on an empty socket), I tested the board; voila "BONG". Took me by surprise. POST screen showed ALL GREEN...I now have sound. Game plays...board revived...unreal.

TLDR: When checking for Bad U1, check the pins on the bottom of the board of the Empty sockets as well. The U1 sound circuit test extends over them...if any pin looks too flat, test it. It might be digging into the board causing a short.

I really hope this will solve some people's "BAD U1" being as simple as a bent pin shorting.

Great work! You’re like the little choo choo train that could! Your determination was unwavering. Congrats my friend