[R-390] Another (perhaps) silly ballast question

[Barry]

Well, I was going to wait until I tried it to make sure there weren't any
"gotchas", but it appears someone else (Dan?) has mentioned this recently.

I kept trying to think of a clever way to get 12.6VAC to the oscillator
tubes -- even to the point of adding a filament transformer somewhere (it
would be cheaper than a ballast tube costs these days and last longer) -- 
when it occurred to me that if the 26.2VAC winding were center-tapped, that
voltage could be used.  That's when I looked at the schematic (and confirmed
on the unit) that the 26.2VAC winding is indeed center-tapped.  This tap can
be run through unused pins from the PS deck to the IF deck.  From the IF
deck plug, I plan to run the wire to an unused pin on the ballast tube
socket and plug in a jumper from that pin to pin 7.  This allows the
original oscillator tubes to be used and if someone decides they want to use
a ballast tube, all that will be necessary is to unplug the jumper and plug
in the ballast tube.

Barry - N4BUQ


> Oh?  Well TELL us what the plan is!
>
> Roy
>
>
>
> - Roy Morgan, K1LKY since 1959 - Keep 'em Glowing!
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