[Collins] 20V-2 motor driven rheostat

Fri May 7 03:14:55 EDT 2004

Dave,
I did not see anything such as you describe in my 20V-3 manual. Keep in mind
there were very few service bulletins on the 20V line. My guess is that this
is someones  "Midnight Engineering". You maybe better off to put it back
stock until you get the 20V-3 on the air.
73 Larry WA9VRH

----- Original Message -----
From: "David Knepper" <[email protected]>
To: <[email protected]>
Sent: Thursday, May 06, 2004 4:58 AM
Subject: [Collins] 20V-2 motor driven rheostat

Could someone please tell me what the purpose is for the motor driven
rheostat that is located on the right rear wall of the cabinet.  I have one
here for my 20V-3 but I believe that Collins deleted this unit since my
schematic/manual makes no mention of it.

Specifically how is the unit connected?  I did connect the wiring from the
front panel lever switch to the unit and applied 120 volts AC.  It does work
but I have no idea where the terminals go on the rheostat itself.

I suspect that it was used to vary the screen voltage on the final amplifier
tubes so as to vary the power output.

Any assistance would be appreciated.

Thank you.
Dave, W3ST
Secretary to the Collins Radio Association
Publisher of the Collins Journal
www.collinsra.com

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