[ARC5] R-23/ARC-5

[AKLDGUY]

Re: the resistor fitted between pin 7 of the 12K8 and pin 7 of the 12SK7.
It's most likely that the heater circuit has been rewired for 12 volts with
pin 2 of the 12K8 now grounded. Pin 7 of the 12SK7 has been disconnected
from that pin and connected via the resistor to the 12V line at the 12K8's
pin 7. The most likely reason for doing this is that someone fitted a 6SK7
instead of the 12SK7. Pull all the tubes and identify them, then check that
the heater wiring is correct for that configuration. 12SK7s aren't hard to
find.

Neil ZL1ANM


On Friday, March 1, 2019, kg4kgl at gmail.com <kg4kgl at gmail.com> wrote:

>
> Good afternoon,
>
> I recently bought a somewhat hacked on R-23. My goal is to get it working
> as a Q5’er with a 12SA7 pentagrid converter frontend for 80 and 40m. I also
> want to keep it looking as original as possible.
>
> I have schematic diagram in front if me and there is a part that installed
> that is not on the diagram. It looks like a ceramic wire wound resistor
> (grey in color) with USN markings. It is connected between pin7 of the 12k8
> and the 12sk7 pin7 next to it. Is this a factory part?
>
>
> Another question. The inside of the top access cover has a small dial on
> it and an adapter for the front tuning mechanism. What is the dial for?
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/arc5/attachments/20190302/eccd4613/attachment.html>