Eden 800 wt: nothing out of left side

[rockman627]

This went out, user complained knobs were scratchy. The roadie opened up the top and sprayed the knobs. Then there was nothing out of the left side. I figured something got disconnected but I'm rarely that lucky. Everything looked good so I downloaded a schematic. I can follow a fender schematic pretty well but this thing sucks.
Well this has got left and right outs so I start swapping out. On the power supply board there are left and right amp outs and left and right speaker outs. Then there are two separate power amp boards.
So first I swap speaker out cables : there is sound out of left, none on right.
Next I swap amp out cables: right amp out to left board, I get sound out of right side; left amp out to right board, nothing anywhere.
This suggests to me that either left amp out is bad or preamp signal doesn't get to left amp out.
Does the signal split in two at the preamp board or at the power supply board?
ps I find it strange signal seems to go from preamp to power supply board to the power amp board then back to the power supply board and out to a speaker output.

[Helmholtz]

Schematic?

[rockman627]

Oops, sorry
this amp has a pm400 board

[Jon Snell]

Just to reitterate, you moved the working amp to the non working side and there was then nothing from either?
Did you put it back and fine the originally working channel started working as it was , or what?

[rockman627]

original problem was left side not working
I removed cable from left speaker out connector, attached it to right speaker out connector, got sound from left speaker
I removed cable from right speaker out connector, attached it to left speaker out connector, got no sound from right speaker
this tells me both speaker outs work. Then I re-connected to original state
I removed cable from left amp out connector, attached it to right amp board, got no sound from either speaker
I removed cable from right amp out connector, attached it to left amp board, got sound from right speaker
this tells me left amp board works. this also tells me signal goes from preamp to power supply board, to amp out, to the amp board, back to power supply board then to speaker out.
I figure the left amp out is not getting signal from the preamp or is not passing it along.
I could narrow my troubleshooting if I knew where the signal splits into left and right.

[rockman627]

I hope this helps. Hopefully the numbers are visible and they are
1 right amp out
2 right speaker out
3 left speaker out
4 left amp out
5 right speaker jacks
6 left speaker jacks
7 right power amp board
8 left power amp board

[Jon Snell]

On the pre amp board you have a volume control, connect pins 1 & 2 of P2 together and if the main mix is OK you will have sound from both amplifiers. Then you can disregards all after the volume control.
Does the bridge mode work?
The way the schematic is drawn will get you to follow the links between the connectors to find what happens with the signal.
Horrible little amplifers.

[rockman627]

Will do when I go back to work Tuesday, thanks. I couldn't find a connector marked P2, but it may be under the preamp tube shield. Bridge mode I forgot to check.

[rockman627]

I found P2 under the light green board next to the tube shield. It doesn't look like the schematic so I did some more hunting and found the attached which matches better although this new schematic seems to be a pastiche of wt800, 500, and 600. It seems you want me to connect post eq fx send to post eq fx left return (p2 pins 1 and 2) , is that correct? Can I just run a cable from their corresponding jacks in the back?
I 've done these things:
Plugged a bass in the front, turned down the master volume, connected first the pre eq send to a deluxe reverb then the post eq send. Got sound both times. Put the master back up.
Plugged a bass into pre eq return, only got sound from right side.
Plugged a bass into post eq left return, only got sound from right side.
Plugged a bass into post eq right return, only got sound from right side.
Put a banana plug into bridge output. With front button on, no sound either side. With front button off, sound only on right side.