One more.

Here's one

Sorry for the confusion in my earlier post.

Peavey Standard 260 from 1972. Isearched for schematic, came up dry. Waiting on PV is to get back.

I installed the new caps correctly. 42 v + & - no access detected.
There seems to be an issued with power to the pre amp. Later versions of this unit specify -15 v on the pin that feeds the cable, ground center.

The p.a. pin reads 42 volts, the center ground, and the pin that should read - 15 reads nothing. I don't know where to start.
I took a couple of pics, one back lit hoping maybe for a clue while I wait for a schematic.
Any hints where to start and what to look for ?

Many thanks.

Wrong schematic. Waiting on PV. Meanwhile, a pic or two
Can you point me in the right direction what to test ?

I have a second identical head which works fine, and I tested around and compared things just to get familiar and everything tested very similarly.
I still have the same weak distorted output.


This is from the post previous to yours. Sorry that wasn't clear in the one you quoted. Here is a schematic too.
Thanks for your help.

  Here is my update :
I got some fuses, fired things up and found I was getting plus and minus 42 v.dc on the rails, I could not detect any ac with my meter.
I have a second identical head which works fine, and I tested around and compared things just to get familiar and everything tested very similarly.
I still have the same weak distorted output.

Here's something I discovered I hope will give you a clue :
On the three pin connector that goes to the pre amp, the pa pin reads -0- the minus voltage pin less than 1volt. If I touch the - voltage pin, I get a weak but audible open ground sound in the speaker,, like when touching a live guitar cord.

I compared it to the working unit, which had + 42 v on the pa pin, and less than 1 v on the - voltage pin. There was no open ground sound when touching the - voltage pin.

Could be. I also discovered one of the solder joints on the cap repair failed. I've had to steal fuses to keep other stuff going, I'll retest and be back.

On a related tangent I have this 150 watt power section from a KB 300 amplifier. Visually it seems a more modern version of the same theme.
If I can connect it to the existing preamp, maybe I would do this. It is dimensionally almost exact.

It seems erratic. A couple of times, it read 48 volts on plus and minus, but then was all over the place.

Thanks for the push,  now I shall learn. I found a schematic in another thread, I am green as a gourd.
The schematic said + - 39 volts, I see where the transformer feeds the rectifiers and the leads off the f.c.'s on the same connector ?
Where do I read the rail voltage ?

Well fellas, as I practiced putting filter caps In a second Peavey amp head I bought to tinker with and learn on,  I made the bonehead move of getting one of the cans reversed and when I fired it up it blew the fuse.

I rewired them correctly and everything powers up fine, but the amp has no output power.
I get a very weak signal to the speakers that is very distorted .

Is it likely I just cooked the caps, or that other things got cooked as well ?
Any clues appreciated, and ridicule richly deserved 

I like that. Simple is good.  :dbtu:

Update, I don't have a scope but do have a decent meter. I'm reading up on how to use it to check for ripple voltage.

I did go ahead and changed out the  filter caps because it was an easy first step as I learn. The old ones discharged a good zap but when the new ones went in everything quieted down a lot,
I do want to learn the test procedures too, I'll be  puttering when I have the time.

This old beast sounds remarkably good with guitar, the distortion circuit is more over- drive voiced IMHO, and gets a nice grit w/o being harsh or tinny. It has a short reverb tank that sounds a little funky, but fine in my view.

It's a little thin for bass in my view, but I like a fat tubey tone. Actually I think this old beast would fit right in with the modern voiced bass amps such as class D etc. but with my Harke bass driver in front it sounds great !

Thanks for the info  Enzo.

I'll go with what you suggested, I just saw the alternate value suggested in an old post. I'll give the other stuff a try as well.

Thanks !

Hey folks,

Thanks for the help already received on this fine forum.

My latest question : I have an old Peavey 260 Standard that has a good bit of hum in the output so it seemed replacing the ancient filter caps would be a good start , (right ? ).
i am aware by search that the originals are no longer available, 5000 uf 55 volts and that some have used these higher values. Will they work ? Thanks.