[ARC5] Why is the ARC-5 Tx rack so hard to find?

[Michael Hanz]

On 3/13/2016 4:22 PM, WA5CAB--- via ARC5 wrote:
> Second, it is actually possible, if you through luck or hard work and 
> much money have all of the other necessary components, to utilize a 
> PL-153 or a PL-153-A at the MD-7 and at whatever control box you have. 
> To do this, first you have to plug socket contact #1 in the PL-153 for 
> connector keying purposes.  Then you drill a clearanance hole for Pin 
> #1 in the face of the connector so that you can physically plug it 
> in.  Second, by default all MT-71 are strapped such that the two 
> transmitters are #1 and #2.  You must re-strap J-75 and J-76 in the 
> mount such that the two transmitters are either #2 and #3 or #3 and 
> #4.  Then you wire the PL-153 per the schematic in AN 16-30ARC5-2 but 
> omitting the wire for SEL #1.  And of course you cannot have four 
> transmitters in the system.

Robert's suggestion above is an innovative one that I had never thought 
of.  If by chance you can find at least one correct 18 pin connector for 
the modulator, some perusal of the 274N and ARC-5 schematics over the 
last few minutes shows a relatively easy pathway to making the 
transition in the cable itself.  Of course, it begins like the recipe 
for rabbit pie:  "First catch the hare..."

Another alternative that Robert frequently mentions is finding a later 
ARC 19830 19 pin connector with the ceramic insert that was used in some 
of the postwar sets - it will fit both the ARC-5 and earlier sets and 
you can plug whichever hole needs to be blank for the set in question.  
I may have one of those around here somewhere if anyone gets desperate.

> A bit of trivia, apropos of nothing in particular, but some combined 
> installations that include AN/ARC-5 did actually use a pair of 
> PL-153.  Just not between the modulator and control box.

Man, I can _really_ appreciate that bit of trivia...  Finding the 
connectors for the ARC-5 set in the aafradio "flight deck" drove me nuts 
for years.  There were a lot of mix and match decisions by the ARC 
engineers, with puzzling choices in when and where to use PL-*** versus 
four digit ARC-5 connectors, especially when you get into the less 
common peripherals mostly associated with the junction, interphone, and 
audio control boxes.  Ya gotta love it or you'll go blind...

That's one reason I suggested that Brother Mcvey give us an idea of what 
he is shooting for in terms of a finished system.

73,
Mike  KC4TOS
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