Acoustic 125 guitar combo issues.. no output!

[crowguitar]

Thanks for the help ..

Thanks for what you've done so far.. getting closer to getting this thing back up and runnin..

For now Ive been runnin out the preamp out into my Tube 100 power amp and back into the speakers.
Just stinks seeing the power section sitting on my workbench lookin lonely and undone..lol

[J M Fahey]

Hi.
Start by using a series lamp, don't plug straight into the wall.
With the amp off check for shorts in all transistors.
If in doubt, pull the suspect one to measure better, but as a general rule pamper the board, avoid pulling components "just in case" .
Measure also the power ones, that's easier because they are socketed, but don't connect them yet to the main board.
Replace what's missing.
Even if you lack a part, see what is still connected to those pads through track or wire, and identify what's missing.
It might help printing a couple schematic copies, and check it part-by-part against the actual board.
Pencil every part you identify on the schematic and, if you wish, mark a small white dot on the actual part on the board, with an office typist correction pen.
Soon you'll be certain of what is mising, and where.
If you can't source 40409/10 you can replace them with Tip31C/32C, *but* the pinout will differ, and you must join the pads where the heat sinks were soldered with a piece of wire, Acoustic designers used them as jumpers.
Your board should work properly, that's to say have around 1/2 Vcc/+B on the + pin of C14, you should have signal there, (without speaker load, output transistors , even without C14) and you should have around 400 to 500mV DC across R¿21? and R24, the ¿50 ohm? resistors. The voltage across those is the actual bias voltage for the power transistors. Acoustics were biased hot, but I preferred to lower that a bit, even risking some slight crossover distortion, because of their non-use of emitter resistors.
Only when you have the board working you can connect the power transistors.
If the wiring is somewhat corroded, (what happened to our friend above), unsolder them (one by one), cut 1/4 inch of the insulated part, peel, tin and re-solder it on the pad, to avoid it cutting when moving the board.
When the amp is fully working, add 0.33r/5W emitter resistors to each power transistor, you don't need a board for that.