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Philmore 12ax7 tube phono oscillator -PA49 AM transmitter
6/25/2006 2:00:21 PMDavid
Hello, I got my hands on this little phono transmitter, but cannot get it to work or power up the tube. I have the original operating instructions, but no schematic. Is anyone familar with this? It is kind of tightly packed into a chassis, so before I start trying to replace caps or check resistors I would like to get some information.
Thanks
David
6/28/2006 11:00:29 PMDavid
Really need help on this one.
6/28/2006 11:19:27 PMNorm Leal
Hi David

Maybe we can help with powering up the tube? Pin #4 and #5 are filaments. Pin #9 is center tap of the filament. To light a 12AX7 you must have 6 volts between pin #4 and #9, also between #5 and #9. Pins #1 and #6 are plates in a 12AX7. You need to end up with B+ on these pins through resistance. I would expect 100 volts or so on these pins.

Norm

:Hello, I got my hands on this little phono transmitter, but cannot get it to work or power up the tube. I have the original operating instructions, but no schematic. Is anyone familar with this? It is kind of tightly packed into a chassis, so before I start trying to replace caps or check resistors I would like to get some information.
:Thanks
:David

7/2/2006 4:13:19 PMDavid
Thanks I will try that. Hopefuly I will be lucky and find a schematic later.


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