[ARC5] R-23/ARC-5

[Robert Downs]

Robert,

 

All of the MF and HF AN/ARC-5 receivers used the same part number tube cover.  So the storage stud for the simplest of the tuning keys is there in all of them.

 

Robert Downs

 

From: arc5-bounces at mailman.qth.net [mailto:arc5-bounces at mailman.qth.net] On Behalf Of kg4kgl at gmail.com
Sent: Thursday, February 28, 2019 17:17
To: Mike Morrow
Cc: arc5 at mailman.qth.net
Subject: Re: [ARC5] R-23/ARC-5

 

I apologize for not appending my name at the end of my questions. 

 

As for the 9554 key being with it. I guess this access cover probably came from another receiver, because the cover does have the threaded place to store the key. 

 

Thank you,

 

Robert S Jenkins

KG4KGL 

Sent from my iPhone


On Feb 28, 2019, at 17:38, Mike Morrow <kk5f at earthlink.net> wrote:

Someone who withholds his name asks:

 

> 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?

 

No, it is NOT original to any version of the R-23.  It seems to be connected to drop the filament voltage to the 12K8, which is in series the 12SK7 filament.  Normally this would be used if the 12SK7 filament drew more current than the 12K8 filament that is in series with it.  But it does NOT.  So unless some non-original tube types with differing current consumption had been installed in the 12SK7 and 12K8 sockets, that non-original current balancing resistor is harmful and should not be used if the 12SK7 and 12K8 will be used with their filaments in series with 24 vdc applied.

 

> The inside of the top access cover has a small dial on it...

If it is calibrated for the R-23/ARC-5, then that is Remote Tuning Dial ID-25/ARC-5. It is to be installed on remote control box C-26/ARC-5 or panel C-125/ARC-5.

> ...and an adapter for the front tuning mechanism.

That is the A.R.C. 9554 Lock-Tuned Receiver Tuning Key. It is normally found only on the stabilized MF/HF communications receivers R-25 to R-27/ARC-5, which were tuned on the ground to the desired frequency using the 9554 key. The 9554 key was then removed from the tuning shaft, turned around, and then screwed on, over the fixture for the  nonexistent tuning cable.  In these common AN/ARC-5 installations the pilot had control of audio level only...no control of emission mode (always MCW) or frequency (fixed before flight).

The 9554 key was not normally supplied with the R-23/ARC-5 (nor R-24) navigation receivers because those were NEVER lock-tuned and always used a C-26 or C-125/ARC-5 remote control.

The 9554 key is NOT intended as a normal local tuning device. That would have been the VERY different screw-on A.R.C. 6743 local tuning control.

 

Mike / KK5F

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