I have an old 2518-17 MPU I’d like to get working for a spare. After I received it I replaced all the brown sockets. It was previously modified per the Pinwiki to accept 2732 ROMs at U2 and U6 and I have verified the modification work. I’ve installed good chips at U6, U9, U11. There are no chips in U2, U7, U8, and U10. Powered up on the bench and LED is locked on. There is some abated corrosion, but I have confirmed good continuity checks on traces/components.

What I have tried:

Shorted pins 40 and 39 momentarily on the cpu chip; The LED did not turn off.
U9 Pin 40 measures 5V
Q1 and Q5 test good.
There is pulse on U9 pin 3, 36, and 37.
U9 pin 3, 36, and 37 measure 2.8V
U9 Pin 2 measures 5V.
U9 Pin 5 measures 2.8v

Can I please get some additional troubleshooting help?

As I understand it, if your board is set up for a single combo ROM, then yes, it would be U2. But this board is set up for both U2 and U6 ROMs (2732's). So I think it I only need the U6 ROM to get the LED flicker.

Just to be clear, I did have all the chips in to start....U2 and U6-U11 and still had the LED locked on. After that I removed the U2, U7, U8, U9, and U11.

Bally ROM set, so I have installed also the U2. Doesn't appear to be any corrosion under the U8 RAM socket. I can take better pics in a while when the sun comes up!
IMG_1998 (resized).JPGIMG_1999 (resized).JPG

OK Quench....shoot me.

I verified (not) the mod jumpers. Thank you for pointing out my error. I installed the missing jumper U6 pin 12 to 18 and got the flicker. Installed the remaining chips and got 6 flashes (no 43V connected). Thank you for the extra pair of eyes!

Well I guess all isn't good yet. Installed in the game but isn't working. Here's a new topic...

https://pinside.com/pinball/forum/topic/bally-rolling-stones-boots-then-freezes