DC Offset?

[Enzo]

Thud is right, if it now blows fuses, but didnlt before, then we have to think you did something to the amp during service.

[dyermaker8]

Ok guys, I'm freakin out a little bit,. I went thru this thing looking for shorts,. open resistors and caps,. and came up empty handed. Looked like all I lost was the two power transistors for the left channel,. so I swapped those out along with q6 & q7 per Enzos suggestion,. put a new fuse in,. put in my series bulb,. turn it back on and the bulb is glowing dim, (if theres a short it would glow bright wouldn't it? Anyways,. first thing I notice is its still stuck on the drive channel,. and still 2 vdc on u7 pin 7 ,. bummer. i'm thinking ok,. nothings getting hot thats good,. and i'm only seeing about 13v on q3 controls channel switching and should have +- 15 v there,. maybe it just needs more juice? So I plug straight into the wall with no bulb,. still stuck on drive channel,. its on for about ,. oh 30-35 seconds ,. and then,. hiss ,. fizzell,. pop,. there goes my left channel power transistors again,. with. I don't bother measuring to see if there bad when they have holes melted in them. my fuse didn't even blow. what gives? I don't get it,. where do I start here ,.

once again,. thanks for the help guys,.

[loudthud]

Those power amps are kind of strange. They look normal until you notice the 220 ohm resistor from the output that drives the junction of the caps bypassing the opamp's filter caps. If your DVM has a diode check function, check the biasing diodes CR30,31,32 and 33. If one of those is open, the output transistors will melt. CR34-37 are a crude current limit, check those as well. That circuit should power up safely with the transistors removed. Verify that the base-emitter voltage is 1.2V or so.