[Amps] General question on filament life

[Gary Schafer]

I think that the tube manuals somewhere state that the 813 should be turned
off if it is idle for more than 30 minutes. ?? Not sure on the time.

73
Gary  K4FMX

> -----Original Message-----
> From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com] On
> Behalf Of Larry
> Sent: Friday, February 09, 2007 11:00 AM
> Cc: Amps
> Subject: Re: [Amps] General question on filament life
> 
> Back to filament life, when I was still working there was a RF heating
> unit buried deep in a classified area. I only knew about it because a
> pair of 3CX1000's would show up on my buddies desk about once a year. He
> said they would go bad because the filaments were left running all the
> time and anode power was only applied when it was needed. I got a pair
> and checked them and sure enough, NO EMISSION! Seems I've seen this
> written up by Eimac or some other manufacturer. Running thoriated
> tungsten filaments without anode current shortens the life time faster
> than on-off cycling. Any comments on this failure mode?
> 
> 73,
> 
> Larry - W7IUV
> DN07dg
> http://w7iuv.com
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