musicman282
Active member
I've pulled the trigger and purchased myself a non-working omega race machine. I was pretty excited when I picked the went to pick the machine up and there was absolutely no acid damage on the cpu board. I figured this would be an easy candidate for repair. The cabinet was in decent condition and all the electronics looked complete. When I brought the game home, I fired it up for the first time and all the lights came on but the monitor had some random lines on it. I opened up the back and saw that the LED was lit on the gameboard so I assumed I had 5+ going to the game board. I decided to clean and reseat all the chips on the board since that is usually what I do when I receive any game. The chips had a lot of corrosion on them and it took me quite a while to clean them all. I put the boards back together and popped them in the machine fired it up and it was doing exactly the same thing. At this point I measured all the voltages coming out of the power supply and they were all within specification. I also measured the 5V rails at each of the rows of chips to makes sure the 5V was consistent on the board. Next, I put the game into test mode and it started flashing ram error codes. I would assume the 2114 ram errors are very common since these are CMOS chips that tend to be highly static sensitive. I ordered some more 2114's from ebay and replaced all of the ones on the board that the error codes pointed to and fired up the game. When in test mode the game now does nothing, no flashes no sounds. The spot killer LED is on the board. I attempted to cycle the test mode into the screen test to try and verify the XYZ voltages coming off the board but it appears that there is no signal coming from the board. I do not have a oscilloscope so I'm kind of limited in tracing analog signals on the board. The game does have some weird behavior though. I tried playing it blind and the game beeps when coined up and the coin meter clicks. The start buttons seem to light up according to how many coins are put in, but the game doesn't appear to actually start when you press the buttons. They just continue to flash and there are no sounds. I tried probing the boards with my meter to check the voltage at some test points to further investigate and accidentally shorted out the -15v regulator at U101. DOH!! Well I'm going to have to wait for that regulator to come in order to continue my troubleshooting. Does anyone have any suggestions on what could be causing my problems. I've been studying the schematics and have a pretty good idea on how the circuit works, I just am wondering if there are common problems outside of battery corrosion that happen with this game.
