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Old March 10th 07, 06:22 PM posted to rec.radio.amateur.boatanchors
Chuck Harris Chuck Harris is offline
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First recorded activity by RadioBanter: Jun 2006
Posts: 270
Default nc-140 running hot

K3HVG wrote:
I'll second that. Both my NC-183,183D, and various other vintage rigs
ran very hot at my nominal line voltage, here, of about 120-125 volts. I
now use a Variac in power distribution line for the older radios and set
it at 110v. The drop in temp of the transformers was dramatic....
There may, of course, be other problems like leaky caps, etc. so a
complete check may be necessary. de K3HVG



One trick you can use to achieve 110V from a 120V nominal power line is
to take a 12.6V filament transformer with a secondary current rating that is
greater than the current drawn by the load, and hook it up as a series
bucking auto transformer... The primary goes across the 120V power line,
and the secondary is in series between the power line, and the radio to
be powered. Pick the 12.6V secondary's polarity so that the voltage drops,
rather than raises. If 12.6V is too much of a drop for your situation, you
can always use a 6.3V transformer to get 115 to 117V.

Much cheaper than a variac.

-Chuck