Peavey CS 800 Blows fuse

[gtrplayr1976]

Here is another link: http://www.geofex.com/Article_Folders/SPO_Test.htm

THAT'S the one I was trying to find ...lol...I knew you or Enzo would post this...

[arambharose]

Thank you ,Thank you,Thank you guys for all the info.So much info so little time.So sad,but keep it coming.
Thank you.

[Jazz P Bass]

Google.
A tech's best friend!

[Enzo]

RGs Geofex web site has lots of little treasures.

On this particular topic, just entering the term in google brings up a TON of the same thing dressed in many ways.

[arambharose]

Is the power to the output boards the molex socket with red,blue,yellow and black I think (thicker wires) .I am about to separate the power supply from the rest of the unit.

[Enzo]

Yes, the four wire connector. It plugs onto the power transistor board itself, not onto the little driver board perched under there. Just unplug it from each power amp module, and power up the amp to see if the basic power supply works. I bet it does. But just for safety, do a quick check on the 35 amp bridge down in the bottom to see if any of the sides are shorted, before powering up.

[arambharose]

Hi Enzo.Amp powers up fine when I separated the power supply from the rest of the circuits.Power LED is on,fan runs and am getting about 80v(+ -)across the rectifier as said on diagram 'C' as you said.I am almost finished building my light bulb limiter as you suggested...will put it into use today.Just thinking ahead a little: 1)PO trans test somewhat like diodes, small resistance one way and open the other. 2)What causes a PO tran lets say in the middle of the row to burn out rather than one at the end....it this related to some component upstream or downstream of this particular tran. 3)Where are you currently buying PO trans from.I live in Boston. 4)One of the rotary knobs on the front panel is missing and the pull out spindle is broken clean off...piece is still stuck in there(got the amp this way). Any ideas where I can get a replacement.I guess that is enough for now.Thanks

[Jazz P Bass]

The output transistors are in parallel.
If one goes belly up in the middle of the row, it was probably hogging current & failed.
There are ballast resistors on the emitters that help with current sharing.
So check those to make sure none of them are open.
But, if the transistor was failing, it failed.
Parts can be purchased direct from Peavey.
They are a great group of people and will go out of there way to assist you.
Peavey Parts Department
To order replacement parts, please call us at 877-732-8391

[Enzo]

Why does this one fail instead of that one in a row of several? WHo knows? I am sure there are reasons a physicist could unravel, but they would not be useful bits of information to you or me. In the middle or in the end doesn;t matter. Although in your case, one end transistor of each row are wired as drivers.

Peavey will sell you any parts you need. I buy the transistors generrically. Most of the MJ15xxx series I buy from Allied, but I always check price at Mouser too.

I don't think Peavey has that volume control any longer, after all, the amp is 30 years old. But ask them. A plain control of teh same val;ue will work, and we just do without the pull switch function. We replace the switch with a wire for on or with nothing for off.

[arambharose]

Hi guys,glad to see we're back up and running.I got both channels to work separately(changed 6 output trans{3 and 3}and 1 diode...P600D I believe..on the power board) but not together.I believe the triac on ch B is gone,because when i flip flop the boards (power and driver together) they work fine.I noticed triac board A is different from triac board B. I drilled that broken gain control out,put a self thread screw in and pulled the broken piece out.Do I need that spindle in there to monitor clipping?Thanks.

[arambharose]

Hi guys,as I said before I got both channels to work separately but not together.Changed both triacs,still same.Any ideas

[Jazz P Bass]

Hi guys,as I said before I got both channels to work separately but not together.Changed both triacs,still same.Any ideas

Exactly what are you trying to do.
There should be a switch on the rear of the unit.
Bridge/Stereo.
Bridge is for running both internal amplifiers into one speaker (cab).
Utilizing one input.
The RED & RED speaker binding posts are used to hook up the speaker..
Stereo is just that.
Two inputs. Two outputs.
If you are looking for a parallel input, that will require an external patch cord to "jumper" both inputs.
Here is a link to the manual:http://www.peavey.com/assets/literat...s/80300991.pdf

[arambharose]

Channel A works fine..When I input a signal into labelled input,sound comes out of the speaker on channel A.When I do the same for channel B no sound comes out of the channel B speaker.Mode is set for stereo.Did you mean the RED and BLACK speaker binding posts or when in bridge mode you use RED & RED.

[Jazz P Bass]

Stereo mode: Red & Black binding posts.
Bridged mode: Red & Red.
So it appears that channel B is dead, huh.
First thing to check: is the Ch B signal reaching the driver board.

[arambharose]

Yes,both channels work(driver and power board combination)when I flip flop them.How do I check if signal is reaching channel B driver board.