Images of Ampeg ST-22, 25, or 42 or layout info?

[glebert]

Working on a 1969-ish Ampeg ST-25 Olympian (schematic here: https://ampeg.com/support/files/Sche...Schematics.pdf). The tech who worked on this before me (and didn't get it working) seems like he was a total madman. Already hard enough with no board labels and then have to wonder what someone put in that isn't supposed to be there. I found a couple of pictures on a wordpress site called the poorpresscollective and used the wayback machine to access them, but they don't show enough detail. Specifically interested in the power amp board.

Thanks,
Greg

[g1]

musicparts has the service manual with board layout. $15 is fairly easy to recoup if it saves you some time.

[glebert]

musicparts has the service manual with board layout. $15 is fairly easy to recoup if it saves you some time.

Hadn't seen that, thanks for the info!

[glebert]

OK, got the service manual. Is the squiggle line here just a wire jumper? Previous dude put a 0.47 ohm 5w resistor which has blown to open.

[g1]

I would guess it's a fuse or a piece of nichrome resistance wire. Where is it in the schematic?

[nosaj]

Since you have the service manual an we don't . Are there other squiggly lines on the drawing that may indicate what it is on another place on the PCB?

Thanks,
nosaj

[glebert]

Since you have the service manual an we don't . Are there other squiggly lines on the drawing that may indicate what it is on another place on the PCB?

Thanks,
nosaj

Yep, did this and it is just a wire. but in reality I was looking at the wrong part anyway, the 0.47 ohm that I was looking for isn't even supposed to be there. For some reason it is hooked up directly from the 40V in the middle of the output section directly to ground. No wonder it burned out. Thanks for all the help.