[ARC5] R-23/ARC-5

[AKLDGUY]

If that's meant to be a criticism of what I wrote, please look at the R-23
circuit diagram and re-read what I wrote. Where do you get the notion that
the resistor is across the 12K8 supply? It's now in series with the 12SK7
heater across the 12V line, making it likely that a 6SK7 was fitted.

Neil ZL1ANM


On Saturday, March 2, 2019, Mike Morrow <kk5f at earthlink.net> wrote:

> If the filaments have been rewired to be parallel instead of the original
> two-in-series configuration, it makes absolutely no sense to have added a
> resistor across the 12K8 filament supply.
>
> Mike / KK5F
>
> -----Original Message-----
> From: AKLDGUY
> Sent: Mar 1, 2019 12:16 PM
> To: "kg4kgl at gmail.com" , ARC-5 List
> Subject: Re: [ARC5] R-23/ARC-5
>
> 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?
>>
>
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