Bugera 6262 crackling/power amp board issue...

[psycle_1]

Still getting 421V on R9 after lifting the socket side of R1 and R3. Not sure where else to go with this.

[psycle_1]

Disconnected MAIN_B again and measured, tube side of R9 is -32V, MAIN_B from preamp board is 421V. This leads me to believe that C56 on the preamp board coming off of pin 1 on the PI has shorted. Correct?

[The Dude]

Then it almost has to be C56. Put everything else back as it should be, unsolder one side of C56, and see if your voltages go to normal.

Edit: Sorry, I was typing when you last posted, but I agree. And, sorry to lead you in circles. I mentioned the coupling caps in post #2, Mick in post #6 and again in post #9. I wrongly assumed that you had checked that cap long ago.

[psycle_1]

Completely pulled C56. Still getting 421V on MAIN_B coming from the preamp board.

And don't worry about me going in circles. I've been going in circles with this whole thing myself before I even posted for help. LOL.

[The Dude]

It has to be a bridge somewhere then. Maybe somebody got the wiring wrong/crossed when they hardwired the connector? That, or there's a solder or trace issue somewhere.

[psycle_1]

Finally got it figured out. R95 on the preamp board (goes to the power tube screens) had burnt slightly on the bottom. Guess what trace runs directly underneath that resistor.... MAIN_B! Pulled the resistor, cleaned the board, and replaced. Voltages back to normal.

[Jazz P Bass]

AWESOME!