I bought a Comet System 9 around 8 years ago and it has been in storage until this week. I double checked the connections. I plugged it in. With the backglass off and the door open I get a 0 listed as a digit in the MPU Display on bootup. It doesn't seem to kick out a ball into play. It doesnt seem to start a game. When I put a ball in front of the plunger and put the ball into play Nothing seems to respond except the flippers. It looks like GI is on but no driven lighting seems to be working. What is my first path of testing? I am assuming that I have issues with the driver board? I am not sure that I have all of the connectors in the backbox installed correctly. IJ9 is not connected to anything but there is a note somewhere that says that it should only be connected to an optical circuit and I know nothing about an optical circuit on comet. Also the digital numerical displays are all unlit. There are no sounds. There is no game to end and no game to start. Pressing any of the tests buttons in the coinbox area does nothing. I have 3 batteries that I put on the MPU board that were brand new when I tested them.

I will post High resolution images of the boards by Friday. I own a DMM with cap testing capabilities and a standard DMM and an analog multimeter.
I am decent at soldering and I own a hakk soldering station and just a plastic solder sucker with a stand for holding boards while I am working on them with led light and magnifying lens on an arm for looking at my work while I am working.