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Re: [TenTec] Switch problem

To: tentec@contesting.com
Subject: Re: [TenTec] Switch problem
From: Bob McGraw K4TAX <rmcgraw@blomand.net>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Tue, 26 Jun 2018 11:51:20 -0500
List-post: <mailto:tentec@contesting.com>
Sailor Bob;

It is a standard garden variety switch.  Probably there is a manufactures number and or name on it.  I'd take it out, connect the two wires together so you can use the radio, and measure the size of the switch.    Mouser Electronics and DigiKey have lots of switches to choose from.

Now with that said, unless the switch is physically stuck,  the switch controls the DC power relay circuit which has a 2N4124 transistor {Q2} in the relay coil path.  This relay actually turns the radio on and off.........not the switch.  The switch only controls the DC power circuit.  It s not uncommon for the 2N4124 transistor to short, thus completing the relay circuit and the relay is always energized, and the radio is always on.   See schematic 81591  DC Input Board.  Some have claimed the relay contacts welded shut and caused this,  but I've never found this to be true.

Do check the switch with an ohm meter for proper operation first.

73

Bob, K4TAX


On 6/26/2018 11:26 AM, Sailor Bob wrote:
My Omni VI power supply has the on/off front panel switch frozen, happily in the “On” 
position. It looks like a standard sort and I wonder if anyone would know of a supplier and part number. 
Looks like it is just a “Plug and play” with slide on connectors. Thanks your interest.

Bob  W2EJG

Sent from Mail for Windows 10



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