well i have yet to pen it up yet, but i was playing last night, and i tried tapping on the head with the volume all the way down and i can still make it pop. Hopefully ill have it apart this weekend and i can get her fixed up.

 

Well i got it apart on my bench right now, and may have already found the problem,,, (I hope). The footswitch jack on the board is totally loose, and all 3 solder joints are broken. I never even realized it, but the nut holding the jack to the face plate was missing, which is probably why the joints broke in the first place. Hopefully this is the problem!!!!

 

Good, you found it. :lol:
Put a dab of glue on the replacement nut. Don't tell my wifey, I steal her nail polish. Shhhhh.

__________________
Uncle $crooge

 

Yes, nail polish is great for sealing screw threads :lol:

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

never tried nail polish, ill have to try that out. Well, as always, i somehow made things worse. I got everything together last night, and took it home and plugged it in. What do you know, i can tap and the crackle is gone. So i am thinking great, fixed. About 5 min later as i am getting my guitar out of the case the amp just starts humming. I plug the guitar in and no sound can be heard, just a loud hum. NO matter what channel i use or anything. I really dont know what could have happened. I was very careful removing the board and i know i did not have any solder drip. I did notice some discoloration around 2 diodes near the speaker output, but i never smelled any burning. Guess ill check them first, but I wonder what caused this..... Keep you posted

 

Okay, one of the two diodes that i saw disoloration is shorted. I think it is a 1n535. I have no problem replacing these, but what would cause it to short like that? I made sure there were no places the board was grounding out or anything like that.

 

What's the circuit reference on the PCB?, so I can see what they do!.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

cr56 and cr57 on the pcb. I dont have the schematic you sent me with me so i assume these labels are on the shemcatic also.

 

Yes, that's the reason for the labeling.

They are 16V 5W zener diodes, used to provide the +/-16V rails from the main +/-40V supply.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

I had my multimeter on the wrong setting, neither is open or shorted. I have 16 and -16 at the correct test points. So what should i look for now? All i get is a loud hum. Does not change with volume, guitar inputs or anything.
I apologize for turning this into such a big post, I probably should have just taken it to the repair shop

 

If it's a seriously loud hum, it could be the ouput stage blown, measure the DC voltage on the output - it should be zero (or VERY close to it).

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

Well its definitely not 0. It is at 40V.

 

It rather looks like you have blown the output stage then :cry:

If you've got 40V DC sat across your speaker it won't have done that any good either!.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

Well i did not leave the amp on for very long so i hope my cabinet is okay.
Upon closer look at the board, i noticed that cr27 diode was not near as low to the board as the other 3 on the heatsink bar. I pulled on it a bit and sure enough it was not even soldered in, or had broken at the joint. Could this have caused it to blow? Is it worth trying to repair the output stage? Thanks again, sorry for all the questions.

 

Yes, if that was OC it would blow the output stages, it's one of four series diodes that set the output quiescent current - if the diode goes OC then the transistors all turn hard on, with disasterous results!.

I would suggest checking all four output transistors, and see if any read SC between collector and emitter. They are commonly available darlingtons, and wouldn't be too expensive to replace.

But make sure you solder CR27 first (and check the other three), if you're REALLY lucky (how many times did you win the lottery last week?), soldering the diode 'might' be all that's required?.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk