[ARC5] R-27/ARC-5 Hookup Question

[Mike Hanz]

On 7/20/2013 10:22 AM, J. Forster wrote:
> I am still puzzled as to why they'd go to the trouble of bringing out the
> terminal. Some assembly line ladies spent years putting in that wire,
> after all!

The marginal cost of including the stripped wire in a laced cable and 
soldering at both ends in a production line doesn't seem very high to 
me, but YMMV.

> If it was useful to serve as a sort of BITE it makes sense- a sort of
> quick final test at the depot or radio maintenance shop- to decide whether
> the radio was OK to go in a plane or needed service.

That seems to me to be a perfectly reasonable context, John.  A quick 
check of the five readings on the I-84 to see whether they were all in 
the proper range would be a way of checking the box on "okay for flight".

> I don't really buy it was put in solely to test the 2x 7000 Ohm divider
> resistors.

I doubt that was the sole reason...there are seldom singular drivers for 
such things, but it was certainly a reasonable way to make an overall 
check...particularly if a given receiver had a log of its five readings 
over time.  I'm not defending the engineering rationale for including 
the capability...it might have been one of those government 
specification gotta-dos that drifted over from the RAT, which also had 
the screen voltage fed to the same rear terminal.

> Can anyone think of another radio that has such a provision?

Don't recall any, but that doesn't mean there weren't one or two others.

  - Mike