[R-390] 51J-4 in Denmark

Fri, 12 Apr 2002 06:38:36 -0500

Hi Clemens, If you are in need of a manual for your "New" find there is one
on the Collins Collectors Association website you can download.
http://www.collinsradio.com/html/manuals.html  good luck with your new find!
Also checkout http://www.collinsradio.com/51J_R388Asur.pdf  for numbers of
J-4's built. I don't remember if there are any service bulletins or service
information letters but they are all located in the CCA Archives on the
website. 73's

Larry WA9VRH
Collins Collectors Association Archive Manager
VP, Collins Collectors Association

----- Original Message -----
From: "Clemens S.Ostergaard" <[email protected]>
To: <[email protected]>
Sent: Friday, April 12, 2002 5:12 AM
Subject: [R-390] 51J-4 in Denmark

>
> Hi everyone,
>
>
> Having been away from the list for a while, I can report a lucky break. I
> have long wanted to supplement my R390A�s and SP-600 with a Collins
> 51J-4. I finally located one, perhaps ex-NATO HQ in Jutland. It turned
> out to be almost unused, the rotary dial not the usual butter-yellow from
> heat and smoking, in its original black wrinkle case, with original
> manual and RCA valves (no tools though). Not a scratch or wear mark, so
> perhaps it has been a spare, or somehow supernumerary. The VFO did not
> need end-point adjustment and it does not vary more than 1-1,5 Kcs over
> the whole range.
>
>
> The s/n is 3026 (at least on the label, on the back the receiver has the
> number 109 stamped not engraved, but I think this is unlikely to be the
> s/n since the manual is dated 1960 and 109 would be from 1957. Any
> comments? Any other places to look for dates, I don�t see any obvious
> candidates?) Front panel is black wrinkle, - personally I like the
> �non-black� versions which contrast with the many black knobs. Perhaps
> only the R-388A came like that? Is that the colour called St.James gray
> wrinkle?
>
>
> It is unmodified, apart from the usual Danish military practice of
> replacing the 51J-4 meter with a small loudspeaker. It has been possible
> (thanks to my friend Ib M�ller) to find a suitable replacement meter ,
> and copy the correct meter scale. Replacement of an electrolytic and the
> missing 100 kcs. crystal, and a thorough overhaul so it looks and feels
> like a new set.
>
>
> The little I have tested it (with a T2FD and a trap dipole) seems very
> promising. It is indeed useful to have the mechanical filter at 6
> Kcs.(and the other two) and the crystal filter gives an early version of
> a notch filter, often effective. SSB is not overly difficult to manage
> and I find the AVC-constant OK. A business-like audio, though at times
> one misses the 8 kcs filter of the R-390A. Amazingly accurate scale, it
> seems equivalent to a length of about 85 yards.
>
>
> Handling this receiver, one can understand why the DOD , on the strength
> of its early version from 1949, asked Collins to create the R-390x, which
> admittedly are a cut above it in complexity, materials and performance
> under extreme conditions. Still, the 51J-4 leaves my wrist feeling a lot
> better, has the right filters and it is a great looker. (and it weighs
> less than two-thirds of our favorite BA)
>
>
> How many were produced? 6-7000? Compared to 55.000+ of the R-390A?
> Perhaps we ought to make a caucus of 51J-4 owners if there isn�t already
> one.(OK, make that 51J-*/R388* owners). Seriously, I would very much like
> to gather any advice, any lore available about this enjoyable set. I know
> there are a number of active people around like Jose, Dallas, W3AKEY,
> Martin Boesch, Dave Knepper, - and likely many others. It is difficult to
> get relevant articles from the newsletters, because they rarely seem to
> make it over the Atlantic. If anyone can help I would  be very
> grateful for that.   I also seem to recall that there were two
> types of Kcs knob, was it improved in later s/n, did people switch it
> from the 75A-4,  and what other changes were made over the course of
> production (1957-1963)? Were the R-388A manuals more detailed than the
> �civilian� version? (which is good)
>
>
>
>
>
> Best,
>
>
> Clemens
>
>
> Clemens S.Ostergaard
>
> Stadion Alle 52
>
> DK-8000 Aarhus
>
> DENMARK
>
> +45 8611 0018
>
>
> BA�s:
>
> R-390A/URR Teledyne Systems Corp 37856-PC-63 s/n 3821
>
> R-390A/URR Motorola 363-PH-54 s/n 1155
>
> R-390A/URR Electronic Assistance Corporation
> -60    s/n 1435
> Hammarlund SP-600 JX-17 s/n 17566
>
> Siemens 745 E 310a  s/n 9/958974
> R-439a/ SRR 11, Magnavox Company, s/n 202
>
> Collins 51J-4 s/n&nbsp; 3026.
>
>
>
>
>
>
>
> --- StripMime Report -- processed MIME parts ---
> text/html (html body -- converted)
> ---
> _______________________________________________
> R-390 mailing list
> [email protected]
> http://mailman.qth.net/mailman/listinfo/r-390
>