Check the 3 lights on the cpu board to the left, what do they do when turning on? Sounds like it's not booting.

Then you aren't getting power from the wpc board. Probably a bad bridge rectifier. Check the power coming into the large wpc board on the far right side near the top and the middle left side nearest the cpu board. Can't remember the exact j numbers but should be easy enough to locate. There are test pins on the wpc also, are those reading the correct ranges? If you have power coming in and they aren't then ya, bad bridge. If no power coming in then check the connection from the isolater right by the power switch in the bottom of the cab.