[Boatanchors] JOHNSON 500 speech clipper mod?

[gary skillicorn]

Not familiar with the 500 but being around from the tube days I recognize that the 6AL5 and 6C4 are entirely different, dual diode vs triode.  Entirely different functions. For starters you sure correct tubes are in place?
Gary. K3GS

Sent from my iPhone

> On Sep 26, 2016, at 5:26 PM, Gary Franklin <franklin6209 at att.net> wrote:
> 
> I have a Johnson 500 which has developed a problem which I believe to be in the audio chain up to the 6B4G driver.  The factory tube line up is:  12AX7 ( first and second audio amplifier),  6AL5 (audio peak clipper), 6AU6  (third audio amplifier),  6B4G (audio driver).   My transmitter has been modified in the clipper stage. Instead of a 6AL5 it has a 6C4 ....  Anyone know of this modification?  could it be a WA1HLR mod??    I also have a small board mounted to the bottom of the chassis which has a SK 3021  NPN power transitor. Handles 300 vceo,  500 vcbo, 35 watt, 2amps in a TO-66 case. On the board is also (3) diodes and a 10K ohm 2 watt resistor.  What mod might this be ???  may or may not be related to the 6C4.
> 
> Gary
> 
> K8BKB
> 
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