/***
NOTE: Just edited for troubleshooting update. Wanted to test channels before I took the amp apart again.
Also inserted a jumper on FX loop just incase.
BTW this is fun, many folks may be discouraged by issues, I eat them up , burp and smile.
**/
/** 1st Updated note:
After todays test I am really thinking somehow I have damaged something in the channel switching circuit. Right now and I mean right now I am able to switch between all modes and all is fine. Each channel sounds great. Well except the RED and ORANGE OD channels which to some who like gain may sound great. Leaving the amp on the rest of the day so I can enjoy playing around with the channels. Also not I have a jumper on FX loop.
Will remove jumper and test later today.
**/
/** 2nd update
Changed v7 again. I do not think is v7 issue, someone mentioned it as a possibility. (I was actually thinking a socket connection
may be bad.....)
If I select a Red or Orange channel than power off and on the channel works fine and so do all the others as long as it is not green that is selected when I power on. Thinking I damaged the IC5a which looks like it controls channel switching or I damaged something in the path. Anyways Amp is working again as long as I do not power up on green.
Leaving as is for awhile so I can practice. And AMP sounds more dynamic than before the choke and xfer mod. Like it is "awake".
**/
Goes to show you no matter how careful you are something goes wrong sometimes. I thought I had taken all precautions but apparently I caused something to fail in the amp after the choke mod.
Replaced output transformer before the choke mod. thinking that went ok as Green clean channel is working.
I operated standby switch with power off to drain the caps before I started. (Read that someplace)
Photographed and drew all the connections to the main board so that I was sure I had everything connected right when done.
Was careful with the drilling and cleaned metal shavings away as I saw them. Shook amp chassis around to make sure I got all the metal shavings out.
I had no issues heating leads on R106 up, used a solder sucker to suck the solder up. R106 popped out. Soldered in the two choke leads with no issues.
I am sure I do not have a cold solder joint as clean GREEN works fine.
Rebiased amp after I was done. (205h so 35mv)
The main board did give me a small issue when I was reinserting. The power tube sockets were a pain to get lined up, used a pencil to assist guiding them in place, I was though careful handing the board. I used the eraser end of the pencil. This is where something could have damaged the board.
The main board was never placed solder side down on any surface.
What I tried:
A visual inspection showed no signs of burnt or melted components.
A good sniffing picked up no burned smells or aromas.
Rechecked connectors and wires
Switching preamp tubes
Amp reset (tried several times)
Effects loop and wet/dry check
Switched the grey control cables from front panel board to main board, switched back.
What I have NOT tried:
I have not switched the power tubes.
I have not reinstalled R106
I have not done a continuity check on every connector
Connecting guitar input straight to effects loop (read this was a good way to see if preamp section has issues)
Continuity check of fuses, just checked visually.
Symptoms:
Edited as apparently I didn't try enough combos.
Clean/crunch channel
Green always works.
Orange works if I first go to OD channel and if the OD channel is working (see OD notes) and I switch back to Orange, Orange works.
Red will work if Orange is working, if not I switch to OD if Red or Orange on OD are working I switch back to clean and Red works.
OD channel
Green sometimes will sound broken up then sound normal after 3 to 5 seconds when first switching to it.
Orange and Red if not working I only have to strum a strings and it pops alive.
Unless my dog or wife played with the parts while I had them apart I thought I was using good techniques. The air here is super dry at the moment I am thinking static electricity got me somehow. My music room is a rubber gym floor and I wear rubber soled shoes... Cotton jeans and shirt.
I was not wearing a anti-static device.
I always touched the chassis before doing anything.This is the price for messing around and I am happy with that. I love pushing big rocks around. I am going to take the amp apart next weekend again and check everything inside and out. If still weird off for an amp repair. I am hoping that the issue is with a component I can replace.
