Re: Filament Issue

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Steven Ward" <srward16-at-hotmail-dot-com> 

You bet its a problem!  The tube needs to be a certain temperature for it 
to go into its normal emission state.  4V is a far far cry of 
10V!  Normally, we use something like a -2%/+5% tolerance for tubes.  So 
you want like 9.8-10.5V on that filament.  Your lucky you did not destroy 
the tube already. Its very bad to run a tube that is not fully heated.  Get 
a new filament supply!


>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: tesla-at-pupman-dot-com
>Subject: Filament Issue
>Date: Mon, 01 Dec 2003 08:03:34 -0700
>
>Original poster: "Jim Mitchell" <electrontube-at-sbcglobal-dot-net>
>
>Hi, I was testing the voltage to the filament on my 813 tube in my VTTC, 
>and I noticed that it was like 4v, when the 813 has a 10v filament!  I am 
>wondering, is this a bad thing?  The filament does get hot, and the VTTC 
>works, but it doesn't work optimum, could low heater voltage cause this?
>
>Regards - Jim Mitchell