Hi, I have a Pioneer SX-780 that I got for free out of someone’s garage. It lights up, source lights come on, and the am/fm meter moves. There is no output, and I’ve tried resoldering the transistors already. None of the fuses are blown or have gone bad. I’ve seen mention of testing the power packs, but I was having trouble getting a voltage reading, so instead I tested for continuity between pins 2 & 3, and 8 & 9 on both packs. Both had continuity on both packs. When I switched to diode tester, I didn’t have a reading. Does this mean the packs are bad? Could someone explain In a detailed way how I test the voltage, more specifically where to put the ground probe?