Re: [TenTec] 260 vs 961 PS

["Bob McGraw - K4TAX" <RMcGraw@Blomand.net>]

In general the supplies are rated for ICAS.  Typical of a 100 watt output 
radio is the requirement for about 20 to 22 amps at 13.8 VDC.  The supply 
has a AUX output rated at 3 amps.  So figure the supply good for about 25 
amps but this is not 25 amps CCS but ICAS.  The over current trip is 
adjustable and usually set for about 22 to 25 amps.
I've noticed with high duty cycle modes such as RTTY, Slow Scan, high speed 
CW and such that additional cooling is desired.  I used a 12VDC fan, powered 
from one of the AUX jacks,  made a couple of metal "L" brackets bolted them 
to the fan and gently pushed the legs between the top of the heat sink and 
the top of the power supply case with the airflow directed at the heat sink. 
No holes were drilled in the supply.  It allows the supply to run a lot 
cooler.
All in all, I've encountered one power supply failure in 15+ years and with 
only one of the 4 that I've owned.  That failure was the bridge rectifier 
mounted on the base plate.  In examination of the failure, I found 
inadequate heat sink compound thus inadequate conduction cooling of the 
item, to be the likely cause of failure.  I replaced the item, added a small 
amount of white heat sink compound and the supply came to life and lived for 
10+ years.  I have since sold the unit and I presume it is alive and well.
As I recall, the difference between the 961 and 962 is the over voltage 
protection circuit in the 962.  Tentec offers the same trade-in value on 
either of them.
73
Bob, K4TAX


----- Original Message ----- 
From: "N4NT" <mike_n4nt@embarqmail.com>
To: <Gary@doctorgary.net>; "Discussion of Ten-Tec Equipment" 
<tentec@contesting.com>
Sent: Thursday, September 27, 2007 8:09 PM
Subject: Re: [TenTec] 260 vs 961 PS


> People say that one power supply will supply 20 amps, another 22, etc.  In
> my opinion, it doesn't matter.  Amateur service is almost always very
> intermittent so overheating is not a problem.  The components of all the
> supplies discussed are fully capable of supplying 22 amps (or 24 amps). 
> The
> only change that would need to be made is in the overcurrent trip point.
>
> Look at it this way: if a supply is rated at 20 amps, then no doubt the
> rating is actually 20 amps PLUS OR MINUS something.  Plus or minus 10% 
> gives
> you 22 amps.  This stuff just isn't that critical.
>
> 73, Mike N4NT
>
> ----- Original Message ----- 
> From: "Gary Smith" <Gary@doctorgary.net>
> To: <tentec@contesting.com>
> Sent: Thursday, September 27, 2007 4:46 PM
> Subject: [TenTec] 260 vs 961 PS
>
>
> > Hi,
> >
> > I'm wondering what the differences are between the 260 & the 961. The
> > most I found out was there were two color variations on the 260 to
> > match the Corsair I & II. I heard there is a greater current carrying
> > ability on the 961 but on this web page it shows both at 20 amps:
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