[Hallicrafters] When do you replace tubes?

[peter A Markavage]

I replace the tube, if the tube is suspect, when the receiver doesn't
work, bellows smoke, or starts to emit strange sounds with random
settings. If I relied on tube tester readings all the time to gauge the
overall tube performance, I probably would be buying a lot more tubes.
Many times, tubes in receivers can be driven almost into the dirt,
barring filament, gas, or element short failure, before they really need
to be replaced.

Pete, wa2cwa

On Tue, 4 Jan 2005 14:56:17 -0800 Waldo Magnuson <magnuson at mac.com>
writes:
> Hi,
>     My question is when do you replace tubes in Hallicrafters 
> receivers. 
>   I use a Hickok 6000A tube tester which is a dynamic mutual 
> conductance 
> and reads out Gm.  As an example in a SX-100 receiver I'm working on 
> I 
> read some of the following measurements:  For a 6AU6 (book value) 
> 2300 
> (measured) 1475 or 64%, For a 6C4 (book) 2200 (meas.)1700 or 77%, 
> And 
> for a 6SC7 (book) 1000 (meas.) 350 & 200 or 35% & 20%, and so 
> forth.
>     My inclination is to replace any tube below 75% Gm reading of a 
> new 
> tube.  What are other opinions?  Thanks.
> 73,  Skip Magnuson  W7WGM