Re: [Amps] 3-500ZG brands

[Pete Smith <n4zr@contesting.com>]

At 10:04 PM 8/11/2004, Clay  W7CE wrote:
> I've just acquired a Kenwood TL-922A which needs a new pair of finals (one
> of the filaments doesn't light up).  Does anyone have experience using the
> Taylor or RF Parts branded 3-500ZG tubes in this amp?  Does the cathode bias
> need to be changed when switching to the 3-500ZG?  Any recommendations will
> be appreciated.


Clay, before you do this, check to be sure that the filament hasn't simply 
opened due to overheating of one of the filament pins.  This is a common 
failure because the tube socket springs weaken with age and the resulting 
resistance between the pin and the socket causes local heating.  I have 
successfully repaired one that had gone this way with silver solder that 
Rich Measures sold me (cheap), and have another awaiting the same treatment.

73, Pete N4ZR
The World HF Contest Station Database
was updated on August 2, 2004
2753 contest stations at
www.pvrc.org/WCSD/WCSDsearch.htm  

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