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

[john rose]

The ARA has pin 7 J3 tied to HV+. There is nothing wired to pin 7 of the rack.
The ARA has pin 5 J3 tied to the screen voltage. There is nothing wired to pin 5 of the rack.

The test setup used (test set 7918 for the ARA) is well thought out. Plug the RX into the test rack, turn on the +28v and in less than a half minute all the "usual suspects" of trouble are pointed out. Saves lots of work and headache.

----------------------
> Date: Sat, 20 Jul 2013 09:57:44 -0700
> From: jfor at quikus.com
> To: aaf-radio-1 at aafradio.org
> CC: arc5 at mailman.qth.net
> Subject: Re: [ARC5] R-27/ARC-5 Hookup Question
>
> Do earlier radios in the family also have it?
>
> -John
>
> ==========
>
>
>
>> 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
>>
>>
>>
>
>
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