[Milsurplus] FS T368 DRIVER TUBE SUBSTITUTES ETC.

[mac]

No transformer required for the 6AV5, just rewire the driver socket  
from the 6.3 volt line brought into the exciter chassis for the  
multiplier string and the PTO.  The 25AV5 works just fine off the 26.5  
volts already wired into the driver socket.  With either tube, though,  
the screen circuit will need to be altered or the plate current will  
be to high.   Replace R120 (the original screen dropping resistor)  
with a  15K 10W  unit and add a 25K ww pot to ground.  The screen is  
then fed from the arm on the pot which
can be mounted on a bracket behind the front panel.  Adjusting the pot  
for 25 - 30 ma driver plate current gives 10-12 ma drive to the 4-400  
on all bands.

Dennis D.  W7QHO
Glendale, CA

****************
On Jun 16, 2013, at 4:30 PM, JOHN Freeman wrote:

> I HAVE SEVERAL  TUBES THAT CAN BE SUBSTITUTED FOR THE  EXPENSIVE  
> TYPE 6000 DRIVER TUBE  IN THE T368 XMTR.ONE IS THE 6AV5GT, ALSO HAVE  
> 3   25AV5GT WHICH REQUIRES ADDING SMALL FIL XFMR TO T368  TO SUPPLY  
> THIS ONE TUBE. ALL NOS IN ORIGINAL BOX UNUSED.  ALSO HAVE ONE NEW   
> EIMAC 4-65A AND ONE GOOD USED ONE. ANY OFFERS?  W7KPB. 		 	   		
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