[Hallicrafters] HT-37/32 bias

[wb8jkr at juno.com]

  The bias should be set at -49 volts with the
rig keyed, but it shouldn't make any difference
if there is RF output or not. The reason being is 
the 6146's run in the AB1 mode which means NO 
grid current, without grid current there can be
no current load on the bias supply so the voltage
between key down with or key down with RF output
should not change in potential.
 Unless of course you are in the CW mode and can
manage to drive the tubes hard enough to cause
grid currnt flow, but even then you'll only be taking a few ma.

Mark  WB8JKR

On Sat, 21 Aug 2004 22:45:51 +0600 Bill <k2wh at optonline.net> writes:
> Al,
> 
> You say the -49 volts must be measured in transmit mode.  I assume 
> you
> mean key down RF out.  The service manual on this adjustment does 
> not
> state this.  It states the bias should be set at -49 volts in MOX
> position.  This could be an important clue to my hot tubes since it
> seems this would allow them to cook at -49 volts in receive or 
> standby
> position.  In transmit, the bias would go even lower.
> 
> I did set my bias in the MOX position, but without any RF output 
> simply
> because I had yet to connect a keying circuit.  I will measure this
> tomorrow and report back to all on my results.  Very interesting!  
> BTW,
> I have just
> started a restoration of an HT-32.
> 
> K2WH


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