Old school Coustic Amp 160:turns on with no remote power

[spooney]

i'll give that a shot . it made quite a stink when i hooked it up backwards although there was never any magic smoke.

[Perry Babin]

That was probably the reverse protection diode (connected across B+ and ground).

[spooney]

i pulled the power supply transistors and they appear to be in working order.I also pulled a couple other small transitors near the remote turn on input but found nothing unusual

[Perry Babin]

When testing the transistors on ohms, you should have only read something other than OL when you had the red probe on the base and the black probe on the collector and emitter. Did you read anything other than OL with any other connections?

[spooney]

no i didn't. the only time i got any reading was with the red lead on the base and the black lead on either the collector or the emitter.

[Perry Babin]

They would appear to be OK.

Does the TO-220 case transistor standing in the power supply feed the small wires on the transformer?

If so, check it. If it's OK, is the voltage from leg 1 to leg 3 more than 0.3v with no remote voltage?

[spooney]

I stumbled upon the problem just a few minutes ago.I was pulling the rest of the small transistors in the power supply when I found a leaky 2n3904 transistor.I threw in an mpsa06 in its place just for a test run and it luckily worked.the amp now only powered up with remote turn on applied.Is the mpsa 06 suitable to use in this application or should i just get the 2n3904?I have plenty of the mpsa06's on hand I just don't have any 2n3904's so if the 06's will work I can get the amp up and running much faster

[Perry Babin]

The A06 is a good sub. There's no need to replace it with a 3904.