[R-390] Best ballast tube resistor

[Jim Miller]

I drilled a 1/4 inch hole in my front panel to the right of the VU meter and
installed a 15W wirewound pot.  I am able to adjust the pot for optimum
operation of the oscillator tubes.  Since the changing filament voltage does
cause a slight frequency shift, this can also double as a vernier tuning
capability.  I am now working on calibrating the dial in Hz offset.  You
must be very careful to avoid turning the pot to zero however, as it will
fry the oscillator tube filaments.  I am thinking of using a sheet metal
screw as a safety stop for this purpose.

----- Original Message -----
From: <TheFirebottle@aol.com>
To: <r-390@mailman.qth.net>
Sent: Monday, May 12, 2003 9:29 PM
Subject: [R-390] Best ballast tube resistor


> Should I use a 39 or 40 ohm resistor to replace my bad ballast tube?
>
> 1%, 5% or 10% and what wattage?
>
> Someone told me that if I use a resistor, my R-390A would not work
properly.
>
> What should I do?
>
>
>
> The Firebottle
> The Original
> Accept No Substitutes
>
>
>
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