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Re: Help with CJ PV-10AL please, hum on both channels

Posted by unclestu52 on July 15, 2006 at 16:45:11:
The PV 10 uses a regulated B+ supply: thats the MJE 340 on the heat sink. Check the voltage being sent to the tubes. Voltage should read about 300 to 330 volts, nothing really higher. Most likely you'll have to replace the mje 340 and the driver which IIRC was an mps a42 (or was it an a92, I can never remember!) There are MPS u10 and u60 equivalents also which may have been used. These are usually the problematic things.
The Large heat sink has the 7812 heater regulator, and you can check that one easily by measuring the filament voltage. r=Remember that CJ runs the filament ground about 45 to 50 volts above true ground, so measure across the filaements for this one.

Stu