Hi Jeff : Do the socket contacts have plenty of spring action to grip the tube
pin ? If not, they get hot and lose their tension. I have had trouble with this
in the past. RCA phono connectors frequently fail to grip the center pin after
a while and this has given me and others grief. 73, Dan, N5AR
Jeffrey Steinman wrote:
> I have an Alpha 78 that one tube occasionally goes "cool" in, as if the
> filament isn't on. Then it
> will come back on and put out full power. Hard to say what causes it to
> change from OFF to ON.
> It just turns on one way or the other at start up. A good smack to the side
> of the cabinet can
> bring it back ON too.
>
> I have pulled the tube out to clean the pins, which looked okay.
> And I used a round toothpick to clean the socket contacts. Seems like that
> helped some, but occasionally
> the tube in question will still be cold at turn on.
>
> Ideas?
>
> Thanks,
> Jeff N5TJ
>
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