[ARC5] [Milsurplus] ARC-5 or SCR-274-N ID Question...More UPDATE

[WA5CAB at cs.com]

The maintenance manual on the AN/ARC-5 LF/MF/HF components started life as 
AN 08-10-195 VOL. 1 dated 23 February 1944.  It was revised several times 
between then and 15 December 1954, when it was rewritten and reissued with 15 
December 1954 being the new basic date.  The publication number was also 
changed (probably in 1945 and probably again in 1946), becoming AN 16-30ARC5-2. 
 I have an original revised through 15 August 1950 which I sell a reprint 
of.  I had an original of the 1954 rewrite but didn't think it was as good a 
manual and sold it years ago.  I do have a somewhat poorly done PDF of it, 
though.

Anyway, having discovered the 3rd IF transformers (except for R-23, 23A and 
148) were missing from the parts lists in both manuals, I set out to 
rectify that, having found something today that the information proved useful for. 
 What I found was that the 1954 manual contains a lot of errors.  It says 
that all of the IF transformers in all of the receivers are 85KC.  On one 
drawing, it says that all of the transformers in all of the AN/ARC-5 receivers 
are the same as in the ARA.  That's only partially true.  Some are and some 
aren't.  And in one case it says that the 1st and 3rd IF transformers have 
the same part number.  Which can't be true for both electrical and mechanical 
reasons.  Anyway, I made up a quicky chart listing the IF transformer part 
numbers (A.R.C. Drawing Numbers) of all of the IF transformers from the 
several places they are shown in both manuals.  I eliminated the obvious errors, 
voted for the later numbers in case of that difference, and revised page 
92A in the 1950 revision of the manual.

If there is anyone still on either of these lists to whom I've sold a copy 
of this manual over the past 30+ years and who wants a copy of the revised 
page, let me know.  

In a message dated 10/25/2009 6:11:14 PM Central Standard Time, 
jfor at quik.com writes: 
> A brief update:
> 
> The 3rd IF on the R-25 is a 9687, not 9587.
> 
> Sorry,
> -John
> 
> ===============
> 
> 
> ReHi Robert.
> 
> On the basis of the data you supplied the UFO set is an R-25/ARC-5:
> 
> You said:
> 
> "To answer an earlier question, the RF coil racks have the same A.R.C.
> number (6220) in both the 46104 and the R-25.  As do the BFO transformers
> (5854).
> 
> But the IF transformers are different.
>         46104   R-25
> 1st IF   7271   9681
> 2nd IF   7272   9684
> 3rd IF   7273   ?   (missing from manual)"
> 
> =====
> 
> The unit in question has IF transformers:
> 
> 9681
> 9684
> 9587
> 

Robert & Susan Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480