Picked up a late '70s Marantz SR-6000 receiver (sorry, no pics before disassembly) in superb condition but not working. Turned in on using the DBT -- the bulb dimmed and it clicked out of protection. Took it off the DBT and turned it on in order to start troubleshooting. Bad move. Within seconds there was a popping sound from the voltage amp board (page 14 of manual) and then a flame out. RN23, a 330 ohm resistor, turned into a heap of molten slag, took out the neighboring diode and blackened the board. The transistor QN07 caught fire and cracked like an egg. Cool stuff! (see pics 1 & 2). I pulled it apart, removed all the burnt bits (pic 3), cleaned the board (pic 4), tested neighboring parts out of circuit, and have since rebuilt it. One thing I did notice was the DC offset pot -- RN09 -- on that side was set to maximum when the flameout happened. Because of my limited knowledge, a couple of questions before I put it all back together and try again: 1) Could the maxed-out offset pot cause the fire or should I be looking elsewhere? 2) I want to check out the power supply board before reassembly. Can I turn the receiver on and get accurate voltages on that board without connecting the other boards? (given the modular nature of most Marantz gear) 3) What's the chances that the STK modules have been taken out? Thanks.