RedSam

Last week I was working on a Peavey M-2600 amplifier. The amplifier was used at the local YMCA youth club and was repeatedly abused. There is an auto-limiter on the amplifier which can be disabled by pulling out the volume control knob. As this potentiometer is physically broken, the knob was pulled out all the time. Volume on max. Enjoying the distortion. It took a while, but the amplifier gave up a couple of years ago. It has been waiting for a repair in my cellar ever since. It sounded back then as if the final transistor stage had given in.

Now that I got my function generator a couple of weeks ago I thought I would finally have a look at it. I disassembled it a couple of years ago so it took me some time to get it working again. I also desoldered some overheated 22$\Omega$ 1W resistors back then which were missing now. I replaced those with four $1\over{4}$W resistors. I hooked up the function generator, scope and some 8$\Omega$ 50W load resistors and turned it on.

Well, it turned out to be working again. It easily delivered lots of power into the load resistors without distortion. I've tested the transistors by measuring the current through the emmiter resistors of the power stage and all of the transistors were taking their part. So after I've replaced the potentio I think I can test it on the original speakers. I don't have any heavy-duty speakers here to hook it up and I won't risk my own living-room speakers for it.

Well, here are some pictures which also show a portion of my working spot: