Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist gang
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Mike -
Yeah, it's not as easy to crowbar a 700V power supply as it is a 13.6V one!
Probably simplest is a thyristor across the AC line (after the fuse!
:-) ) and drive it through an optocoupler from the bias supply. An R/C
delay on the coupler to give the bias supply a few seconds to come on,
and after that if the bias drops to x volts POP! It really shouldn't
happen but once, and a fuse is cheap compared to finals, etc.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B & C-Line Service Supplement CDs
<www.k4oah.com>
Mike Bryce wrote:
Mike Bryce <[EMAIL PROTECTED]> made an utterance to the drakelist gang
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Gosh..
I thought about that, but here's no way to crowbar the bias circuit.
in the old supplies, the damage is caused by a "lack" of bias. So, if
there is a failure of the bias supply, i.e. it quits, how can you fix
that?
the only way I could come up with would have been a system that
deprives the transformer of it's primary voltage, shutting down the
supply. It would have to default in the off position too, as you would
not want the supply to cycle on, find the missing bias, then shut
down, the power up, find the missing bias supply, shut down and on and
on.
mike
Mike, WB8VGE
SunLight Energy Systems
The Heathkit Shop
http://www.theheathkitshop.com/
J e e p
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On Dec 15, 2007, at 5:28 PM, Bill Horne wrote:
Bill Horne <[EMAIL PROTECTED]> made an utterance to the drakelist
gang
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Is there a provision in the kit for a crowbar circuit to safeguard the
rig if the bias (or other) supply fails?
Bill, W1AC
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