Where can i find the schematics for bugera 333xl

SOURCE: Bugera 333XL Amplifier does not power up. Valves do not light.

Steve,
That's a nice amp head.... If it is still blowing fuses, you've got a dead short somewhere, that probably is in the power supply section. The power supply is solid state, (diodes for the rectifier), so either one or two didoes went bad or one of the big filter caps shorted out. Look for a blackened area around these components. Sometimes the caps will have just a "puffed-up" look to them, but.. BE VERY CAREFUL! Some tube amplifiers do not have bleeder resistors on the caps and they can hold a charge of up to 450 volts... Very dangerous! AND can KILL.
If you don't know what those components are, or how to use a volt/ohm meter, you should take it to a technician.

Donald DCruz

• 17130 Answers
• Posted on Jul 24, 2010

SOURCE: bugera 333xl every few seconds there is a loud buzzing. from

It looks as though you have ripple noise that amplifies into the output. First of all check if the mains voltage is going down to produce the low voltage hum. If not you will have to check the DC filter capacitors , couple in parallel to confirm the capacitor. IF the buzz is still coming through then you will have to isolate the preamp and wait it the fault is coming in. If not connect the preamp output to another amp to hear the same buzz to confirm the preamp to be faulty. If so you will have to trace by a voltage check when the buzz occurs to confirm if the preamp IC or the selector Ic is faulty. Some logic IC's can also produce this noise on static switching. If teh noise is appearing on both the channels, then I would still bet on the power section. So check once again on the rectifier/ regulators and capacitors. Hope this advice helps. Good day