[Boatanchors] 51J3 receiver

[Jim Wiley]

To all BA types -


I have a Collins 51J3 receiver that is excess to my needs. This is a 
genuine Collins manufactured set, not a military contract clone.  If 
anyone on this list is interested, I would prefer it go to someone who 
will appreciate what's there.  If no one here expresses an interest, it 
goes up for auction.


The gory details:  It powers up, it is reasonably clean, and is complete 
(no missing or substitute parts) - I would rate it a "good" overall, not 
showroom excellent, but a bit of time, elbow grease,  and some judicious 
use of cleaners could restore it to factory fresh appearance.  No 
modifications, extra holes, or other non-factory stuff.  No dents in the 
metalwork, no significant paint dings or scratches.  Black wrinkle paint 
typical of the era. One military type acceptance stamp on the top corner 
of the front panel.  Serial number 4786. 


The 51J3 is typical of the Collins receivers of the era, extremely well 
built, literally mil-spec construction.  The 51J3 is basically a general 
coverage version of a 75A3 ham receiver, although some of the circuitry 
is necessarily different to permit the wider  coverage.  Coverage is 500 
KHz to 30 MHz, continuous, in 1 MHz bands.  Of course it features the 
famous Collins PTO frequency control with 1 KHz resolution direct 
readout, just like the "75A3" receiver.  I can provide a photo on 
request, but a quick search of a Collins collectors information site 
will doubtless bring up what you need. I don't have the book or 
schematic, but these are available for free download from BAMA or other 
archival sites. 


All controls work smoothly, all functions work, dial plastic is not 
yellowed, no cracks observed on any of the plastic parts, dial  bezel, 
or knobs.  Controls are "free" and not "noisy".  Dial drum shows slight 
yellowing, but I think that is an artifact of the anti-fungus coating 
the military loved to spray over everything.  It receives signals on BC 
and several short-wave bands, the crystal calibrator says it is pretty 
much on frequency.  Have not checked the tubes, and would not be 
surprised to find some weak ones.  I will supply brand new tubes, where 
I have them, on request.   There is a small chip missing from the dial 
drum that affects only the 29.8 MHz area of the 29-30 MHz band, and is 
not visible on other bands.  This could be repaired by someone with 
patience and some rub-on (dry-transfer) lettering. Alternatively, I have 
seen replacement dial drum overlays offered by various sources.  


The set could  probably benefit from an overall alignment, but I have 
neither the time or the instructions needed to do this.  It did seem to 
meet spec as far as sensitivity goes - roughly 1 microvolt for 10db 
signal+noise to noise at 3.8, 7.2, 10.0, 14.3, and 15.0 MHz.  I didn't 
try other bands, but the "noise" picked up on a short antenna definitely 
indicated it was working. 


The date stamps stay 1952 vintage.  Has top and bottom covers, but no 
cabinet.  Mounts in a standard 19" rack - or in a ten and a half inch 
high 19" rack cabinet.   I removed the top and bottom covers to see if 
any smoke escaped when I was bringing it up, but no problems were 
found.   I did bring it up slowly on a Variac.   Main power supply 
capacitor has been correctly reformed, and shows no leakage at 400 volts 
DC.  The capacitance is within spec (supposed to 30 + 30 uFd, measures 
40 + 42 uFd).  I can supply a NOS "spare" replacement for this plug-in 
part.  Most of the other caps are either micas or oil-filled paper 
"bathtubs".  No "black beauty" type caps.   Has both 600 Ohm and 4 Ohm 
audio output connections.   Requires external speaker - not supplied.   
50-Ohm SO-239 type (standard "UHF" type) coaxial antenna connector.   
Has a standard 2-wire line cord.  In the interest of safety, I would 
suggest changing that to a more modern 3-wire grounding cord and plug.  
Your call there.


This is a relatively heavy set, and would come in at about 75 lbs. after 
being packaged.  Shipping via insured FedEx ground will run about 
$100.00.  Packing material (double boxed and bubble wrapped) will be 
about $25.00.  According to the local FedEx representative, shipment 
will  actually be via air cargo  from Anchorage to the FedEx hub nearest 
your town, then via ground for the final stage.  I could probably get it 
to you for somewhat less by the postal service, but that would be your 
call.  I tend to trust FedEx more than the USPS with fragile items. 


Asking $ 400.00 + shipping or best offer.  I accept checks, Visa or 
MasterCard, or pay-pal.  Again, please contact me off list:  KL7CC (at) 
ARRL.NET   


Questions?  Ask I and shall try to answer. 


- Jim, KL7CC
Anchorage, AK