[Boatanchors] Johnson T-R Switch # 250-39

[rbethman]

On 9/23/2015 9:59 PM, Ron Youvan wrote:
>
>> Based on other Electronic T/R switches I have seen the Power Transformer
>> is most likely 125 - CT - 125 volts 50 ma high voltage side and the
>> filament is 6.3 volts at an amp. A Stancor PS-8416 may work
>
>   I have seen similar transformers in one tube audio turntable preamps
> and slightly more robust ones in two tube (stereo) preamps, but either
> may have 12 Volt filament windings.  (for the 12AX7 which is operable
> with 12 or 6 Volts)

The Johnson T-R Switch, Catalog # 250-39, supplies 190VAC to the 6X4 on 
pins 1 and 6, with a Center Tap to ground, and then the 6BL7 is fed 
170VDC during receive on pins 2 and 5, the two plates.  During transmit 
the 6BL7 plates are at 190VDC.

It is NOT like others!

Regards, Bob - N0DGN
[ Tired Old Sarge ]