[Collins] re KWM2A V13

Dr. Gerald N. Johnson geraldj at weather.net
Wed Feb 1 22:11:12 EST 2012


On the mixer stage, a shield may affect the balance. The shield base 
helps some. Otherwise its probably a matter of heat. I've seen the 
subject of shields argued for weeks on other Collins forums. There are 
beneficial thermal shields and bright polished shields (the lowest cost 
ones, of course) that tend to cook tubes like being in an oven. The best 
ones are the IERC with the black phospher bronze fingers inside that 
cool the glass and are all black. Those are the ones that snap in place, 
they don't bayonet lock. Sields also help keep tubes in the sockets in 
mobile applications which is one of the intended applications of the 
KWM-2/2A.

ASAB1004 suggests a circuit change to make V6 run cooler.

Remember the 2A is not a later 2, its a 2 with the extra crystal board.

73, Jerry, K0CQ,Technical Adviser to the Collins Radio Association

On 2/1/2012 1:59 PM, Rick Gouge wrote:
> I have one more question around this KWM2A. I have a tube sheild on V6 but there is no sheilds on V 7&  V 5. Are they left off for a reason or should i put them back on? Rick VE7RiK
> ______________________________________________________________
>


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