Hey guys. I grabbed this Tascam 302 unit for $15 and its clean inside and out but does not power up at all. I checked the power button and voltage selector on the back and they were good. I measured the voltage out of the power transformer and it read 18.6v DC. The schematic I looked at said it should be 12v but maybe 18v is ok since nothing is on and there are no loads. I removed the main PCB and the other two and they are all squeaky clean on both sides. No bulging caps or anything. What should I look at next?