[Amps] 3-500ZG brands

[Pete Smith]

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
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