[TenTec] Non-Ten Tec PS Switching Methods

Dr. Gerald N. Johnson geraldj at weather.net
Sun Mar 28 12:34:28 PDT 2010



On 3/28/2010 12:49 PM, Curt wrote:
> I power my 540 with an SEC switching power supply rather than using a Ten
> Tec 262M or 252M.  This after reading about pass transistor failure issues
> and retrofitting crowbar circuits it just seemed too much trouble and risk
> to try using these old supplies.
>
> The only issue I'm wondering about is turning off the rig by turning off the
> supply.  Of course the rig slowly dies as the PS caps bleed off.  I guess
> maybe the Ten Tec supplies somehow avoid this when mated with a 540.  What
> are other folks doing if anything to connect up to a non-Ten Tec power
> supply.

The tentec supplies do nothing about that, except to put the power 
switch on the volume control, so to turn the supply off you turn the 
volume control so you don't hear the rig die slowly as the power supply 
runs down the capacitors. Its also possible that the TenTec supplies 
don't store as much energy in their filter capacitors and their output 
voltage drops faster because of the high drops of the linear regulators.

What I did with my Corsair II with my station supply was to make up a 
power cable with a relay. The relay coil has a diode in parallel with it 
to kill inductive kicks and then I put a diode in series with the low 
power line voltage rated switch in the Corsair II to make the assembly a 
reverse polarity protector. I used an automotive 30 amp cube relay. The 
spade lugs made assembly convenient.
>
> 73, Curt KB5JO
>
>73, Jerry, K0CQ


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