I put a diode in series with the relay coil to make it an amplified
polarity protector too. I also put a diode across the relay coil to
squelch inductive kick.
It was intended that the switch in the rigs controlled the power supply
primary. Supposed to survive better that way. Same thing was planned in
the Collins 32S transmitters and KWM-2 and those switches (looked like
switches from a pot mounted on a rotary mode switch) also are known to
fail. Its beginning to be a popular mod to add a power relay to the
Collins AC supply because those switches are special and hard to find.
I presume replacing the switch on the Corsair is not a trivial shopping
task. Used to be you could find a distributor of TV and radio parts that
could make up any control combination, but that's no longer true. For my
part of the Collins 821A-1 I made up a control out of TV parts that had
the switch at the clockwise end of rotation. Took some cobbling and
soldering to make the first one, but once written into a specification
production units were on hand when I needed them even for a production
run of only 9 units (that were completely replaced once so I used at
least 18 special pots). I didn't ask the price. Just that for a manual
PA drive pot, I wanted a detent and switch at full drive, which was full
clockwise end of rotation.
Even more commonly if it was a volume control with tubes it invariable
was a half meg audio taper and the one variations needed were in the
shaft and those kits had a wide assortment of shafts from smooth to
serrated to splined to split and serrated with and with out flats that
fit every possible knob variation. Sometimes similar pots are available
from distributors of parts for fixing guitar amps these days.
73, Jerry, K0CQ
On 1/2/2011 2:48 PM, Bwana Bob wrote:
> Jerry:
>
> Thanks. I have the original breaker that Ten-Tec used on the Corsair
> and it translates to an Airpax "instant trip", which are scarce. The
> fast trip appears to be an acceptable substitute, though. I'll look
> into the specs on the ATC fuses. A 5 amp fuse might be a good choice for
> my Century 22, instead of a breaker. ATC fuses are certainly cheap and
> plentiful. Good idea on the relay, too. My Corsair on/off switch
> controlled the AC input to the power supply, but it still eventually
> burned up. I haven't gotten around to replacing it. I just use the
> switch on the T-T power supply.
>
> 73,
>
> Bob WB2VUF
>
> On 1/2/2011 1:29 PM, Dr. Gerald N. Johnson wrote:
>>
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