[ARC5] Starting work on BC-453B

[Todd Bigelow - PS]

David Stinson wrote:

> Jim Mandaville wrote:
>
> > 1.  What is likely to be causing the oscillation? (I'm suspecting bad
> > bypass caps) or voltages too high on the R.F. stage).
> Most definately bad caps.  You can get around this problem
> without changing the caps by running both filaments and B+
> at 24 VDC.  An amplified speaker will give you plenty of audio-
> the are available and cheap from any computer surplus outlet.
> All control and audio connections are available from the
> connector on the back skirt- no need to drill anything.
>
> > 2.  Is 47 mA about the right current draw, or does this indicate leaky
> > caps?
>
> > 3.  What caps should I check as most likely to be leaky (I'm assuming
> > the ones that handle plate or screen voltages or those in the input
> > filter.
>
> The caps mounted in the round tubs on the side are ALL bad- I promise.
> Those that are not leaking now will be leaking
> after several hours at full B+.  This will cause the failure of
> other componants when they short.  If you run the rig at low B+,
> it is likely you'll not have to change any of them, or at most
> one or two.

I'm guessing there's no trick for doing this (24v B+) if you intend to use
the original dynamotor because it creates all the necessary voltages
including 250v? Part of the reason I want to restore mine is to use them in
the original configuration with the DM-32s. The only thing that comes to
mind is changing the pins inside the radio on the dynamotor base and wiring
them both to the 24v pin and disconnect the 250v altogether? Minimal mod,
but I still hate to do it.