[NJARC] BC-348Q Power Questions(2 of them)

[Jim Whartenby]

You must either have put in a series resistor in the B+ line of the
power supply or you have a leaky capacitor somewhere in the radio that
is causing a tube to draw excessive current.  350 volts peak X 0.707
should give you 250VDC RMS.  For whatever reason, you have an
additional loss of 60 volts in the B+ power supply.

Open the B+ line and check the current drawn by the radio.  If it is
more then the dynamotor is rated at, then you have an issue to resolve.
 Also check the audio output tube for the negative bias on the control
grid to chassis ground.
Jim

--- Scott Roberts <ng19delta at yahoo.com> wrote:

> Visit our web site - See http://www.njarc.org
> _______________________________________________
> Hi John-
> I was shooting for 228VDC, after rectification, filter
> & 2 electrolytics, it was 350VDC. Under load, it is
> 190VDC or so. Just powering up the radio brought it
> down there.
> 
> Scott
> 
> --- john ruccolo <jr6v6gt at yahoo.com> wrote:
> 
> > Visit our web site - See http://www.njarc.org
> > _______________________________________________
> > Hi Scott,
> > 
> > How did you finally get the B+ down in that power
> > supply? Hopefully *not* by overloading it with a
> > low-value bleeder resistor. Do you know how much B+
> > current you're drawing?
> > 
> > I thought you said you needed (or wanted) 250V?
> > 
> > BC-348's are fun to play with, aren't they?
> > 
> > Regards,
> > 
> > John
> > 
> > --- Scott Roberts <ng19delta at yahoo.com> wrote:
> > 
> > > Visit our web site - See http://www.njarc.org
> > > _______________________________________________
> > > Well, after the meeting Friday, I got onto
> > > tightening
> > > up the power supply I was building, and finally
> > got
> > > all fitted in and set up last night. End result-
> > > 190VDC under load, so not so bad I suppose. I seem
> > > to
> > > be pulling in signals on all bands at this point.
> > > I'd
> > > had a small issue with the BFO adjustment- I'd
> > > absent-mindedly and inadvertantly turned the shaft
> > > with the knob off, and had to reset it. Happily, I
> > > had
> > > directions to do so in the BC-348-Q tech manual,
> > and
> > > it took only a minute to find the zero beat, and
> > set
> > > it. Seems to work quite adequately. There is still
> > a
> > > slight hum, I need to figure out where to throw in
> > > another electrolytic to filter it out... May just
> > be
> > > the volume control needs cleaningI do notice
> > > differences with vc fiddling)
> > > 
> > > Now if I can improve the antenna...
> > > 
> > > So far, I've been pulling in signals from assorted
> > > hams, Canadia,(where Canadains come from), Radio
> > > Havana, Cuba(very loud and clear &
> > > non-pro-American),
> > > Canadian time signal, Chinese broadcasts...Oh
> > yeah,
> > > religious all over the place, as usual. Had a nice
> > > vox
> > > received and listened to for a bit- one e nd was
> > in
> > > Wisconsin, and it was a nice strong signal.
> > > 
> > > On to the next project!
> > > Scott
> > > 
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