It`s hard to say - see the answer to the similar message. You can try to measure all the voltages on tube sockets, even without opening the cover. If you don`t know how to mesure HV safely and check the bias - maybe trip to the tech is in order?
I checked all the pin voltages on both 6L6's with the tubes pulled. They are as directed. Got nice heater volts, 500v B+, and -50v bias on the grid. I'm lost. Short of simply changing out the electrolitic caps, I'm looking for a techy guy to take over! Thanks again JAMES
If all those voltages are OK, then chances are that you`ve just had the bad tube. Try another good tubes, but look to the plates - if they turn red, switch it off immediately! (The proper metod, of course, would be monitoring cathode current through small R=10 Ohms between cathode and the ground - 30...40mA of standing current.)
Well, this might be my lucky day. With all the voltages okay, I used a trouble light and magnifying glass and found some cold solder joints where the tube socket meets the PC board. A few minutes later, bingo! I THINK the trouble has been resolved. Can tell more later. Again thanks for all the tips and ideas...JAMES
With absent negative "bias" voltage on g1 (pin 5), the tube "draws" large current and quickly overheats. PCB traces can be "intermitent" `cos of heat, vibrations and by pushing tubes in the sockets. Clean burned carbon marks (conductive) on the tube socket, if old tubes remained any. Good luck!
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