Figuring out OL, OH Dig Dug PCB error

I have gotten a little motivation back, and took a little time to investigate this further.

I had been going back and forth with Bob Roberts on this chip, and without even looking at my board I was able to kind of figure out with his help that this chip was plug in play, which meant it should be socketed and no soldering necessary. Plus, since it was PnP, that meant I didn’t have to burn anything to it either. He said the chips are very sensitive and this is fairly common.

In the Dig Dug manuals, it says that a OL and/or OH error are due to a bad RAM. It just depends on what version of the Dig Dug PCB you have to find the location on the board. If you have Revision A, the position is 9M, and if you have Revision B of the PCB, then it is position 4K.

I thought for sure these positions would be printed in the manual, but they weren’t. I pulled the board out and did a comparison of component side elements on the board to the two drawings in the manuals. I have a Revision B Dig Dug PCB, so that meant my bad RAM was at 4k.

Here are some photos of the PCB. I circled the 4k labeling, it might be hard to see. Also a photo of the bent RAM and the RAM in the socket.

Dig Dug PCB RAM labeled JAPAN 2E1 HM6116P-3Dig Dug PCB Empty Socket at 4kDig Dug PCB RAM with bent

I took a look, and it was obvious. There my RAM set, with the front leg bent and barely in the socket. I was floored, how had it worked up until now? It might be as simple as taking that chip out, bending the leg back, and the game might work. Well, I did just that, and it didn’t work. So I am guessing that after so much time of it being almost bad corrupted the chip.

I am checking with Bob to see if he has that chip. The number on the top of the Chip says JAPAN 2E1 HM6116P-3. Would like to get a larger order of stuff to bring down the total cost for the one part, but if it means getting the game sold, I may not wait.