[AMRadio] Intermittent Filament

WE0H we0h at yahoo.com
Mon Sep 17 23:35:11 EDT 2007

Does the pins or socket contacts look like they got over heated? Any 
solder dropped out of the pins? I have read about resoldering pins but 
the plating eventually is gone so the solder won't stick. Even so too 
much heat could compromise the pin to glass seal. If that is the case of 
soldering, I would try silver soldering if you could get in there and do 
it fast with a high wattage iron.

Just what I have read online, no experience personally. If indeed that 
is the failure, make sure you run better cooling on the sockets when you 
do repair it or replace both the sockets and tubes so the contact to the 
pin is absolutely perfectly clean and super tight.


Rick Brashear wrote:
> I have a 828 pentode with an intermittent filament.  When I tap on the glass
> it will usually stay lit as long as power is applied and sometimes comes
> back on when I've removed power.  When it's lit it works beautifully.  It
> seems I've heard guys talk of a hit and miss method of restoring filaments
> in some cases.  Does anyone know anything about this?  I know we used to
> rejuvenate picture tubes by applying certain voltages to them.  I think I
> still have my old CRT rejuvenator/checker around here some where.
> Any info would be much appreciated.
> Thanks,
> Rick/K5IAR

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