[sdiy] calling tube gurus...this old rare one has the most peculiar filament problem

[Roy J. Tellason]

On Wednesday 23 January 2008 05:20, Bob Weigel wrote:
> What could be going on here.   I've got a Teisco amp ..a very old one
> that I'm repairing for a guy who does the Teisco amp page.  It uses a
> 6Z-DH3A  and yup that is the actual tube number.

I sure don't run into those too often.  :-)

> It's a preamp tube.  I fortunately have a working one but it measure real
> low on quality check.  But at least it lights up.  This one does not
> HOWEVER...both filements measure good on dc test. Both a little under 4ohms. 
> 3.5 and 3.8 on the bad one..which..is actually a brand new tube I believe.

That might be a bit of manufacturing variance there.  Maybe.

> Resoldered the bottom but did no good but now I see that it obviously
> wouldn't.

Are we talking about an octal base here?  I don't seem to have a datasheet on 
that one.

> That filament is stone cold but theo ther lights in my Jackson tester.  I
> get no measure on it of course at all since the filament..really really
> isn't lighting at all.  I can shield the tube from light and there is no
> glow at all. -Bob 

I'm not sure what you're saying here,  you get no heat on which one?  But you 
measure good DC resistance on both of them?  Please elaborate...

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