http://forums.peavey.com/viewtopic.php?f=19&t=22056

Scroll down to the 7th post. Someone posted a picture of the poweramp board from a 260 H. The one to the left is most definitely 680.. at least I think! I am seeing blue, grey and brown. The other resistor is more difficult to see. Certainly did not try to measure! They are both burned completely in half.

i used the diode test function on my dmm to test the output transistors. I checked for shorts only, and found none.

Recently purchased this head from a guy on Craigslist for $50... Once I got home, I plugged it in, and then... nothing. There is a "thump" when you plug the cab into the amp, though. Checked the output and I am getting almost 40vdc from the speaker output. Cool.

Two resistors were completely fried, and one of the driver transistors was actually melted. I tested the four to-3 output transistors, and they checked out OK. The driver transistors seemed bad. at least one had a short between collector and emitter/base. I tested all the smaller to-92 transistors on the board, and wasn't able to come to any real conclusion, but am going to assume they are BAD. In any case, I ordered all new transistors, except for the output ones.

In the picture, the fried resistor to the left (680 ohm) reads -42v on one side, and 21 on the other. I assume this is a symptom of a dead transistor. The other fried resistor is a 100 ohm.

Anyway, just want to make sure I am on the right track here. No schematic available, only a few pictures online. I've e-mailed peavey for a manual.

That was a mistake, the voltage is positive on both sides! While poking around, I noticed that Q13 is getting very hot, and is likely shot. I'll update after I replace the suspected components.

my power rails are fine, and cr1 has been replaced, +19vdc/-19vdc on either side of the diode. speaker is most definitely good. Is there any one "good" source to purchase these transistors? Mouser has these:

2N5190G: http://www.mouser.com/ProductDetail/ON-Semiconductor/2N5190G/?qs=sGAEpiMZZMshyDBzk1%2fWi7XVVUd4Z%2fsloAY%2fGWX12hs%3d (unsure if the g suffix renders this unusable)

2N5193: http://www.mouser.com/ProductDetail/STMicroelectronics/2N5193/?qs=%2fha2pyFaduhbgd5uuHMvGRKH%252bqgO6VbWRtgqLDohffA%3d (appears out of stock)

2N4921G:http://www.mouser.com/ProductDetail/ON-Semiconductor/2N4921G/?qs=sGAEpiMZZMshyDBzk1%2fWi%2fPUgtclNldlaxfxMPQa9Mo%3d

Thanks for the help!

Thanks for the replies. I drew in red the location of the "mystery" resistor that does not appear on the schematic.

teemuk; it is more likely revisions were made and the schematic was not updated. It is definitely the schematic for this amp, I was unclear on that.

There is no DC voltage being sent to the driver. I use (impedance matched) "junk" speakers when testing, anyway. I had a bulb limiter that I built, but it was lost in a move and have yet to build another.

Hello all, (obviously) my first time posting here. I've been building and repairing tube amps for some time, but solid state technology is uncharted territory for me.

I recently acquired an old Jordan Entertainer amp. There is very little information available online regarding this amp. In fact, the schematic inside of the amp is actually wrong. The amp was working for awhile, until it was jostled while playing, and made a loud hum. I found that the rectifier diodes were physically damaged. i replaced them, and the amp worked for awhile. I was playing, and the same thing happened, this time taking a resistor with it. this resistor is wired in series with a diode, connecting the base of two output transistors. the schematic inside of the amp does not show this resistor, only the diode. the resistor was so completely burned, that it couldn't be identified. i replaced the resistor with a 22k and replaced the diode as well.

so now, the amp powers on again, and stays on with no issues, but no sound. only the slightest bit of 60hz hum, which is not noticeable until your ear is placed right on the driver. with the volume maxed out, the hum gets only SLIGHTLY louder. the amp has spring reverb, and you can actually HEAR sound coming from the springs/tank itself. So, SOMETHING is working, but it isn't the output section.

Seems it would be obvious to replace the output transistors, but before I do that I want to make sure there isn't something else I might be missing?

EDIT: I suppose I should clarify, when I say "the same thing happened" I'm referring to the symptom (hum), and not the physically damaged rectifier diodes.