Egnater Tweaker 40 Channel switching doesn't work

[tripwire]

Bought this amp with a bum PT; put in a ClassicTone, and it came to life, but..... no channel switching. I can't seem to find a pre-amp schematic (I have the power section available here). I emailed Egnater, and they said to plug in the foot switch (duh) and make sure the output ohms switch is good. Any other emails (with pics) haven't been answered. Should be a simple fix..... anyone done one? Right now I have the preamp board out, which is a major PITA on these amps. Thanks for any help.

[pompeiisneaks]

If the channel switching isn't working you'd want to troubleshoot the relay power supply etc.  Check that you're getting the right voltages at the relay coils when it's engaging.  That or make sure the relays themselves haven't gone bad for some reason.  Did you fix the reason the PT fried?  It may have taken out some of the SS components tied into the switching PS like a regulator etc. 

~Phil

[tripwire]

Thanks for your reply. I'm stuck on checking for voltages without the benefit of a schematic. Lots of relays in these things. Someone changed a diode on it in the relay section, so I'm starting there. Hope that someone has one of these that they're working on, as I have another question about a jumper that is on the bottom of the board, but it may be factory. Still no response from Egnater. Don't buy one of these things.... an old amp is much easier to work on.

[VMS]

Did you see this old thread, maybe tubegeek can help you:


http://el34world.com/Forum/index.php?topic=16958.0

[pompeiisneaks]

Weird that you're having a hard time with their support, Bruce is all over Facebook on the amp groups responding to questions and starting his amp building classes etc.  If you're on FB you may want to look up the groups like

tube guitar amp builder
tube guitar amp modifications

stuff like that.  I don't recall the exact group(s) he's on, but several I think.  I'm on like 5 different ones related to amps.

~Phil

[tripwire]

I went directly to Egnater. My first question was answered by Blad. The other 2 questions are still out there. I just wanted to know if the jumper on the bottom of the preamp board is stock, and to get a schematic. I'll try Gear Page later. This is a great site, though!

[pompeiisneaks]

Sadly I don't know the amp myself, if I had a schematic, I too could look it up.... sorry!

~Phil

[MFowler]

I put in a replacement power transformer in one of these and had to get data to understand all the connections.

Mark

[sluckey]

Bought this amp with a bum PT; put in a ClassicTone, and it came to life, but..... no channel switching.

Which ClassicTone transformer did you use?

I'm looking at the spreadsheet for all ClassicTone power transformers and I don't see one that has secondary windings capable of powering all that SS circuitry in that amp.

[mresistor]

It's probably this one Steve   -    http://www.classictone.net/40-18104.html

[tripwire]

I think this amp may have had channel switching problems even before the transformer blew. One of the diodes near the relays has been changed, and they did a crappy job. There's a jumper on the bottom of the board that goes to a couple relays. I was hoping to get a schematic to see if it's a factory jumper. There's a seperate schematic for the pre-amp. The schematic posted here was for the power section (which was handy when I installed the transformer).

[mresistor]

On an engineered and factory produced PCB I doubt there would be any jumpers underneath.

[tripwire]

Good point!

[pompeiisneaks]

On an engineered and factory produced PCB I doubt there would be any jumpers underneath.

I guess that depends on what you qualify as a 'jumper' in my head dual sided boards with connections on the bottom aren't visible but are technically jumpered no?

~Phil

[mresistor]

Well he wasn't specific but I assumed he meant "someone added a jumper" to the bottom of the board.

[tripwire]

2 jumpers in fact. I'm removing them and putting it together to see what it does. Probably a blown relay; the diodes seem fine around the switching relay. Sorry I wasn't more specific.