{Collins} Re: Tube compatibility.



Justin:

I would only put very late production tubes in this unit and any you get 
you should test in the unit.  What they do to cut the power back
in the tune position is to cut back on the screen grid voltage in these 
tubes.  When they do this the voltage regulator is disabled as well
in order to accomplish this. If you by chance get tubes that are have 
excess gas in them it will cause the screen grid voltage to fall below
what was intended in the tune position and you will have problems with the 
unit exhibiting the proper characteristics during tune up.

This transmitter is not tolerant of tubes that are not just right.


Kurt Keller



At 08:51 PM 10/16/2004, you wrote:
>I am looking at purchasing a pair of 4X250B tubes for a KWS-1 transmitter
>(So I can have spares) and I was wondering if anyone has had any luck with
>substituting a 4CX250B, 7203, or 4X150A?  I have seen varied reports of
>compatibility on line, but wanted to get some general feedback before
>trying anything.
>
>Thanks,
>
>Justin.
>Sponsored by the Collins Collectors Association http://www.collinsradio.org
>Nets: Tues: 3.805 Mc-2000 Central / Thur: 3.875 Mc-2000 Central
>Fri: 3.895 Mc-2000 Pacific / Sun: 14.263 Mc-2000 UTC
>1st Wed (of the month) AM Net 3.880 Mc-2000 local (ET, CT, MT, PT)
>Sun AM Net: 29.050 Mc-1200 Central

Sponsored by the Collins Collectors Association http://www.collinsradio.org
Nets: Tues: 3.805 Mc-2000 Central / Thur: 3.875 Mc-2000 Central
Fri: 3.895 Mc-2000 Pacific / Sun: 14.263 Mc-2000 UTC
1st Wed (of the month) AM Net 3.880 Mc-2000 local (ET, CT, MT, PT)
Sun AM Net: 29.050 Mc-1200 Central






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