Fred -
That technique is normally done when troubleshooting a 'new' piece of
gear to protect power transformers, etc. when a radio is in unknown
condition. It's really not indicated for operation.
The AC-4 power supplies all THUMP at turn-on, depending upon where the
AC waveform is at the instant the switch closes. I've never seen a bad
transformer in an AC-4 that hadn't been destroyed by too big a fuse or
other mis-treatment.
The 'correct' fix is a 'thermistor', or 'inrush current limiter', which
is a device shaped like a large disc ceramic capacitor. It is a
temperature dependent resistor that has a specific resistance when cold,
that drops considerably when it heats up from the current through it.
They are not expensive, but do get quite warm in operation, and of
course affect power supply regulation. Selecting the appropriate one is
a bit of a pain, you want one that starts out high enough to limit that
initial inrush current, yet drops to a low enough resistance when hot to
minimize regulation.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs
<www.k4oah.com>
[email protected] wrote:
/Has anyone heard any additional information about using a light bulb
in the AC line ahead of your radios ac input to reduce the inrush
current to the rigs as they are turned on. I would like to hear more
about doing that if the information is available. It seems there is
quit a surge when I turn on the transmitter Drake T4xB./
//
/Thanks /
/73 de Fred WD8ADG /
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