I can't catch a break with my Congo. One issue after another since day one. I was playing it for around 30 minutes last night, everything was fine, and it just went dead in the middle of the game. No lights, no dmd, no sound, nothing. Only thing that works is a volcano led strip mod. It connects to an unused PLFD connector on the driver board that seems to get constant power. Leds on the boards work so appears boards are getting power. Fuses all check good using multimeter. On bootup, the bottom cpu led (202) is always on. The top (201) comes on during cold bootup, fades, and then barely on with a flicker. The cpu gets pretty hot very quickly but not sure if that is normal. Last night after running for 30 minutes, the top 201 led never came on after power cycle. The middle 203 led is always off - never blinks. No bongs on bootup - only a slight normal buzz sound. Does same thing if I disconnect all cables on the cpu board except power.
Before this issue, I was having switch matrix short problems. One column was out that controlled lower playfield CONGO target switches and AMY switches. Hitting one of those switches got a row short. Replacing the U20 chip fixed that but it happened again later. Only thing I did was pull the playfield out and rest it on the rails (power was off). I threw in another U20 chip and it was working fine for several days. Perhaps related to current issue.
The cpu board was treated for some minor battery corrosion last Fall but someone local. It was working fine at the time but wanted to make sure it was not an issue later. I don't think anything was replaced - just neutralized, cleaned up, and battery holder replaced. I've used a remote battery holder since I got the game so no chance of new corrosion. Some of the solder joints still look a bit suspect, though. Not sure what it looks like when bad and doesn't look as bad as some pics I have seen. I also don't like the looks of the chip marked "BA10339 523 L03" and the D28 thing next to it. Looks like corrosion or something leaking. I suspect the cpu boards need repairs but like to have some idea of what is going on. Any help would be appreciated.