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Re: [TenTec] 252G Power Supply question

To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Subject: Re: [TenTec] 252G Power Supply question
From: "Mike Hyder -N4NT-" <Mike_N4NT@charter.net>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Tue, 18 Jul 2006 18:33:34 -0400
List-post: <mailto:tentec@contesting.com>
Someone else can tell you the procedure.

But I wish to alert you to a potential problem.  The 252G and supplies of 
that genre did not have a crowbar circuit.  This means that if the pass 
transistor shorts, the supply feeds some 25 volts to the rig.  Ten-Tec used 
to sell what they called an OVP, an overvoltage protective circuit.  That 
was a small circuit board which mounted inside the rear panel of the supply. 
The large red wire that goes to the power output is cut and soldered to that 
circuit board.  You can easily spot that O VP if it is installed.

Recently Ariel K4AAL provided us with a better solution, a self-contained 
device that performed the function.  I quote his email below.

From:  "Ariel M. Elam" <k4aal@comcast.net>
      Reply-to:  k4aal@comcast.net,Discussion of Ten-Tec Equipment 
      Date:  Wed, 22 Feb 2006 23:32:33 -0600
      List-post:  <mailto:tentec@contesting.com>

Here is a method for providing a quick and easy crowbar.Place a Diodes
Incorporated  1.5KE15A (NTE4920) across the power output AFTER the fuses
and before the rig. Band goes to +. It will clamp 1.5kW, about 100
amps@15 volts and blow the fuse.

I found this in "73 Amateur Radio Today", May 2002, page 38. Title "An
Ounce Of"

73, Mike N4NT

----- Original Message ----- 
From: "Craig Roberts" <crgrbrts@verizon.net>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Tuesday, July 18, 2006 6:07 PM
Subject: [TenTec] 252G Power Supply question

> Hi y'all,
> I've just acquired an old model 252G power supply which I plan to use
> with my Corsair to avoid sharing my 963 supply with my Pegasus.
> When I tried the 252G with the Corsair it tripped the overload circuit
> at about 15 amps (60 watts or so).  The incremental adjustment of a pot
> inside the supply -- which I assume is a current limiting device -- 
> cured the problem, but I'm curious as to how the setting should be made
> "by the book." This supply seems barely adequate for the transceiver.
> Many thanks and 73,
> Craig
> W3CRR 
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