[Milsurplus] Smart People: BC-9A Opinions Needed

[AKLDGUY .]

Hi Dave

I believe you have the polarity of the 120-V battery back to front. The way
you have it would put -ve
onto the first tube's plate. The green wire in my opinion is the effective
"Ground".

73 de Neil ZL1ANM


On Wed, Jan 4, 2017 at 4:51 AM, David Stinson <arc5 at ix.netcom.com> wrote:

> Good morning.  There's precious little specific information technical on
> the WWI-era BC-9A
> (SCR-77A) battery-operated, portable CW set.
> Some general descriptions but no clearly-copied schematic.
> https://goo.gl/photos/uVYek56Zoja1jqQq6
>
> There is a schematic on the inside of the cover, but mine was stained and
> missing a large part
> of the center of the diagram.  I have worked with what I could find to
> re-create the diagram.
> Please look at this photo.  The re-created part
> is in the green outline.  It is close to the smeared,
> obscure copies I've seen but not certain.  Does
> this circuit make sense to you?
> https://goo.gl/photos/RCMKFHrZKZBHoeLc7
>
> Next:  I'm working on power supply solutions
> (other than the obvious batteries.)  I need to do some RF bypassing in the
> supply lines and need
> a point I can call "Ground" in this circuit.
> This diagram- Red lines appear to me to be
> what one would think of as "RF Ground," while
> the 120 and 40 B- lines reference in green.
> That puts B- above the "RF Ground" by the filament bias, adding to the
> grid bias on the tubes.  Do you think my analysis of
> the red line being the place I could think of as "Ground" is sound?
> https://goo.gl/photos/bucwyMuC12jdfWWT7
>
> Thanks for your input and prosper in 2017.
> 73 DE Dave AB5S
>
> ______________________________________________________________
> Milsurplus mailing list
> Home: http://mailman.qth.net/mailman/listinfo/milsurplus
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Milsurplus at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/milsurplus/attachments/20170104/bd89f20c/attachment-0001.html>