R-388/URR Contract Info Pager388-rm1c-01.JPG (180449 bytes)

R-388/URR Serial Numbers

Contract serial numbers are stamped into the ID tag on the front panel - they start over for each contract Collins production serial numbers are stamped into the rear panel near the REMOTE terminals. They may also be painted underneath the ID tag.

Production numbers started matching contract serial numbers around 1956

 

1951 USN contract s/n: 280
r388-usn-280.JPG (128585 bytes)

1957 Signal Corps contract s/n: 58
r388-urr-id-30951.JPG (18321 bytes)

Collins # 3293
r388-usn-rear-1201.JPG (64169 bytes)

Collins # 3293 under ID tag
r388-usn-front-1201.JPG (127641 bytes)

Late model R-388 and 51J-4 have a 3-digit number ink stamped on the rear - it often matches the 51J-4 ID tag s/n.

51J-4A with stamped 3-digit number
51j4a-04.JPG (124504 bytes)


Why do Collins serial numbers and contract numbers and models seem to be mixed up sometimes?

From Collins historian Bill Carns - Collins built all equipment under a line (MCN) number and then put it in inventory. All equipment including the A-4 was not serialized until it had been purchased or scheduled for shipment to a distributor and then it went through an outgoing QC step and was serialized upon passing the QC check. After the war, and for many years, the fellow doing that function was named Gurney. The process of outing a radio became known as "Going to Gurney". Long after Gurney retired, and to this day, the process of pulling, checking and serializing a radio is known as "Going to Gurney"......even though he is long gone.

The other thing that happened (from Dennis Day and Gene Senti) is that, if there was a need for a receiver in the engineering lab (working on service bulletin issues or the like), the engineers would pull a receiver from inventory (un-serialized) and take it to the lab and use it for however long they kept it, which could be a long time. It then was returned to inventory, got pulled for an order, and then was serialized in the current numbering system and shipped. This resulted in early units being shipped much later in the serialization string.

There is another factor that aggravated, or confused the issue. Collins did not use a FIFO (First In First Out) inventory control system like many companies did. If things moved around or got in a corner they could be there a long time.

So, ... all of this makes our life a little more interesting when we try, for instance, to date a radio by component date code - They did not use FIFO on their components either.


US Navy AN/URR-23A = R-388 + cabinet + speaker

Contract NObsr-52527 (22 June 1951) for 280 systems (R-388/URR + LS-199/U + CY-1235/U)
Manual NAVSHIPS 91678

Distinguishing Characteristics?

Speaker Jack
 - no "Break-In" switch

1 tag or 2 tags

urr23a-02.JPG (228086 bytes)
Photo from NAVSHIPS Manual
urr23a-102.JPG (40040 bytes)

System ID tag on cabinet

r388-urr-02.JPG (31698 bytes)

R-388/URR Tag from NObsr-52527
note - receiver also has holes for a second tag


R-388/URR Contracts - Info originally compiled by Tom Marcotte

With ** notes added by Nick England

Navy contract summary -


Illustrative photos

r388-urr-02.JPG (31698 bytes)
Navy contract NObsr-52527
note - this unit also has holes for a second tag
r388-usn-280.JPG (128585 bytes)
Navy contract NObsr-52527
note - this unit does not have holes for a second tag
r388-urr-id-19624.JPG (14573 bytes)
Order 19624-PHILA-50
showing both tags

1908-phila-51-tag.jpg (19136 bytes)
Order 1908-PHILA-51 with 2 tags

r388-urr-id-3096.JPG (13087 bytes)
Order 3096-PHILA-51

r388-halli-00.JPG (35905 bytes)
Hallicrafters R-388 manual
Order 3131-PHILA-51-01

3109-tag.JPG (14900 bytes)
Order 3131-PHILA-51 showing 2 tags

r388-halli-1103-05.jpg (50113 bytes)
Hallicrafters R-388 manual
Order 3167-PHILA-51-01-C
r388-halli-1103-03.jpg (73730 bytes)
Hallicrafters/Collins unit
3167-PHILA-51
r388-halli-1103-01.jpg (85341 bytes)
Hallicrafters/Collins unit
3167-PHILA-51
Hallicrafters R-388 cabinet - these R-388's have rollers at the rear corners to fit into the cabinet slides.
r388-halli-1103-02.jpg (72704 bytes)

cy1260-r388-1210-01.jpg (69237 bytes)
cy1260-r388-1210-02.jpg (68230 bytes) r388-urr-id-3357.JPG (41367 bytes)
Order 3357-PHILA-52
showing 2 tags - this Signal Corps unit also has USN inspection stamps.

r388-c25.jpg (12957 bytes)
Order 3357-PHILA-52
Serial C 25 - what does that mean?

r388-urr-id-3362.jpg (18517 bytes)
Order 3362-PHILA-52 

r388-1302-01.jpg (9926 bytes)
Order 3470-PHILA-52

r388-91.jpg (19993 bytes)
Order 25635-PHILA-53-36

r388-92.jpg (44951 bytes)
Order 25635-PHILA-53-36

 

r388-urr-id-25067.JPG (95281 bytes)
Order 25067-PH-54-55
tag and Signal Corps stamps

56-138-tag.JPG (246669 bytes)
Order 21318-PH-56 s/n 138 (also has "138" stamped on rear) - thanks to RJ
56-138-rear.JPG (69285 bytes)

r388-urr-id-30951.JPG (18321 bytes)
Order 30951-PH-57

r388-62-294.jpg (48278 bytes)
Order 37003-PC-62

r388-uscg-1201.JPG (50700 bytes)
USCG Order TCG-38466

51j3-201.jpg (51102 bytes)
51J-3 ID tag - is this original or a repro?

51j3-man-01.JPG (51032 bytes)
51J-3 inspection tags
51J-3 part number is 505-2193-035

51j4-tag-11.JPG (14258 bytes)
Early 51J-4 ID tag? But I think it is actually a reproduction, not an original.

51J4-tag-5501.jpg (626469 bytes)
Later 51J-4 ID tag

r388-raytheon-01.jpg (559789 bytes)
USMC overhaul contract NOm72487
r388-raytheon-02.jpg (756881 bytes)
USMC overhaul contract NOm72487
r388-raytheon-03.jpg (652935 bytes)
USMC overhaul contract NOm72487
r388-raytheon-04.jpg (806757 bytes)
USMC overhaul contract NOm72487
r388-urr-03.JPG (21950 bytes)
R-388 with Navy anchor inspection stamp (behind missing ID tag) - but with Signal Corps second tag

r388-usn-sc.JPG (66045 bytes)
Navy anchor inspection stamp overlaid by Signal Corps stamp

r388-usn-front-1201.JPG (127641 bytes)
Collins production # ink stamp under ID tag and Signal Corps stamp

6109-usn.jpg (22512 bytes)
USN inspection stamp on crossbar (s/n 6109) 

 

 


6109-anchor.jpg (10098 bytes)
Navy anchor inspection stamp (s/n 6109)

r388-usn-rear-1201.JPG (64169 bytes)
Collins production # stamped on rear

  r388-inspec-01.JPG (952859 bytes)
1956 inspection stamp
Order 21318-PH-56

r388-3914-jack.JPG (43607 bytes)
speaker jack  (3096-PHILA-51)

r388-25067-switch.JPG (22527 bytes)
break-in switch ( 25067-PH-54-55)


Field Change break-in switch (s/n 6109)
Note different "O" lettering
r388-urr-05.jpg (123788 bytes)
R-388 showing Collins production # 6626 stamped behind missing ID tag
r388-urr-rear-note.JPG (49726 bytes)
R-388 rear showing MFP stamp and Collins production # stamped into metal
3109-01.JPG (59519 bytes)
R-388 reworked per 1953 MWO with flat finish, new lettering, and break-in switch
r388-urr-04.JPG (77129 bytes)
R-388 with Navy ID tag and break-in switch - this seems wrong as the break-in switch didn't appear until later
r388-urr.jpg (163364 bytes)
R-388 with two missing tags and speaker jack
r388-urr-102.jpg (16376 bytes)
R-388 contract 37003-PC-62 showing FCC Part 15 certification stamp in center, yellow AGC jack, and green DIODE LOAD jack - MFP treated
r388-62-294-04.jpg (73423 bytes)
Order 37003-PC-62 serial 294
almost the last R-388 built?
r388-62-294-01.jpg (48278 bytes)
r388-62-294-03.jpg (46305 bytes)
R-388 contract 37003-PC-62 showing FCC Part 15 certification stamp in center, yellow AGC jack, and green DIODE LOAD jack - not MFP treated
r388-62-294-02.jpg (102443 bytes)
R-388 contract 37003-PC-62
r388-1705-01.jpg (171544 bytes)
R-388 contract 37003-PC-62 s/n 168 with "0035" and winged logo stamp on rear
R-645/GPQ-3 (51J-3) s/n 7
Collins production s/n 9151
"Look, ma, no handles...."
r645-gpq3-02.jpg (16454 bytes)
R-645/GPQ-3 (51J-3)
r645-gpq3-03.jpg (15412 bytes)
R-645/GPQ-3 (51J-3)
r645-gpq3-04.jpg (21604 bytes)
R-645/GPQ-3 (51J-3)
r645-gpq3-05.jpg (19885 bytes)
R-645/GPQ-3 (51J-3)
r645-gpq3-08.jpg (17930 bytes)
R-645/GPQ-3 (51J-3)
r645-gpq3-13.jpg (122193 bytes)
R-645/GPQ-3 (51J-3)
r645-gpq3-14.jpg (130302 bytes)
R-645/GPQ-3 (51J-3)
r645-gpq3-15.jpg (114543 bytes)
51J-3 rear panel with MFP, production # 6027
51j3-202.jpg (142363 bytes)
Early 51J-4 - no FCC stamp, no AGC or DIODE LOAD jacks, "313" ink stamped serial number - not MFP treated  
51j4-rear-early.JPG (83166 bytes)
Later 51J-4 rear showing FCC Part 15 certification stamp in center, "457" ink stamped serial number, yellow AGC jack, and green DIODE LOAD jack - not MFP treated  
51j4-rear-02.JPG (18177 bytes)
Later 51J-4 rear closeup  
51j4-rear-03.JPG (18841 bytes)
51J-4A - Westrex Corp. 
- thanks to KA0JW
Please e-mail with any additional info
51j4a-01.jpg (2514817 bytes)
51J-4A
51j4a-02.jpg (662460 bytes)

51J-4A rear
51j4a-03.jpg (1157200 bytes)

51J-4A stamped "225"
51j4a-04.JPG (124504 bytes)

Australian 51J-4
51j4-aus-01.jpg (129183 bytes)

51J-4 Collins test unit - s/n 105
Collins production # 048
51j4-gray-105.jpg (216683 bytes)
51J-4 gray test unit with R-388 ID tag
51j4-gray-1312-01.jpg (92516 bytes)
51j4-gray-1312-02.jpg (89657 bytes) 51j4-gray-1312-03.jpg (98071 bytes) 51j4-gray-1312-04.jpg (124009 bytes)
 JK1VXE's interesting site with photos of  several R-388 models (in Japanese)  

Info on Reproduction R-388 ID tags


R-388 Data Base - please send me more info

- contract s/n is on ID tag and started over with each contract
- Collins production # is stamped into metal on rear and/or inked behind tag - continuous numbering
- info gathered from web photos, email submissions, & personal observation
- note "FC" means obvious Field Change switch installation

R-388 Listed by Order Number (Contract Number)

Contract & contract s/n ID tag holes Break-In Switch
or Speaker Jack?
AGC/Diode jacks on rear? Meter Manuf Collins production # & Other Info

Navy Contracts

NObsr-52527  2 tags speaker jack no holes for 2 tags but only 1 installed
NObsr-52527  2 tags speaker jack no holes for 2 tags but only 1 installed
NObsr-52527  2 tags speaker jack no holes for 2 tags but only 1 installed
NObsr-52527 ??  1 tag speaker jack ? (I can't read contract number)
NObsr-52527 (s/n 97)  1 tag speaker jack no # 4229 
NObsr-52527 (s/n 97)  1 tag speaker jack no # 4823
NObsr-52527 (s/n 160)  1 tag speaker jack no -
NObsr-52527 (s/n 243)  1 tag speaker jack no # 5462 (MFP 11/51)
NObsr-52527 (s/n 256?)  1 tag speaker jack no # 1196 (MFP 11/51)
NObsr-52527 (s/n 265)  1 tag switch- factory? no # 8771 (possibly wrong tag?)
NObsr-52527 (s/n 280)  1 tag speaker jack no # 5480 (MFP 11/52)
Navy ???  ***  1 tag speaker jack no (MFP 1951) - anchor stamp
Navy ???  1 tag switch- factory no # 2818 (MFP 3/52) anchor stamp
Navy ???  2 tags speaker jack ? anchor stamp

Coast Guard Contract 

TCG-38466 (s/n 45)  1 tag speaker jack no # 1769 (MFP 1/52)

Air Force Contract 

AF 30(635)-778 (s/n 7)  1 tag speaker jack no # 9151 R-645/GPQ-3

Army (Signal Corps) contracts

19624-PHIL-50 (s/n 2) 1 tag switch- FC no # 446
switch added and front panel refinished
19624-PHILA-50 (s/n 146) 1 tag speaker jack no # 235 (MFP 7/51)
19624-PHILA-50 (s/n 402) 1 tag switch- FC no (MFP 9/51)
"MWO 11-5820-0202-35/2"
19624-PHILA-50 (s/n 495) 1 tag speaker jack no Burlington  photos
19624-PHILA-50 (s/n 666) 1 tag speaker jack no -
19624-PHILA-50 (s/n 816)  1 tag speaker jack no # 267
19624-PHILA-50 (s/n 1005)  2 tags switch- FC no non-wrinkle paint - photos
19624-PHILA-50  2 tags speaker jack  ? Marion  photos
1908-PHILA-51 (s/n ??)  2 tags switch- FC no # ??
1908-PHILA-51 (s/n 2)  1 tag  switch- FC no # 8465 - late for contract date
- glossy black panel repaint
1908-PHILA-51 (s/n 404)  1 tag switch- factory no # 8756 - late for contract date
1908-PHILA-51 (s/n 478)  2 tags speaker jack no # 1072 (MFP 10/51)
1908-PHILA-51 (s/n 694)  1 tag switch-factory no # 7352 - late for contract date
1908-PHILA-51 (s/n 706)  1 tag switch- factory no # 8386 - late for contract date
3096-PHILA-51 (s/n 148)  1 tag speaker jack no # 3353 (with add-on mech. filter kit)
3096-PHILA-51   1 tag speaker jack no Burlington  photos (with add-on mech. filter kit)
3131-PHILA-51 (s/n 116)  2 tags speaker jack no - TEST jack # 1404 no MFP
3131-PHILA-51 (s/n 281)  2 tags switch - FC no # 3109 - switch added and front panel refinished per MWO SIG 11-264A-1 for AN/GRC-26A (1953)
3131-PHILA-51 (s/n 413)  2 tags speaker jack no # 1575 (MFP 12/51)
3131-PHILA-51 (s/n 432)  2 tags speaker jack yes - FC # 2498 (MFP 02/52)
3131-PHILA-51  2 tags switch - FC no -
3135-PHILA-51 (s/n 1363)  2 tags speaker jack no # 4134 (MFP 07/52)
3164-PHILA-51 (s/n 33)  2 tags speaker jack no   # 4214 (MFP 07/52)
3164-PHILA-51 (s/n 129)  2 tags speaker jack no # 4009 (anchor inspection stamps)
3164-PHILA-51 (s/n 184)  2 tags speaker jack no # 5810 (USN and anchor inspection stamps)
3167-PHILA-51 (s/n 227)  2 tags speaker jack no # 4622 (MFP 8/52)
with Hallicrafters CY-1260/G cabinet
3167-PHILA-51 (s/n 364)  2 tags speaker jack no # 3517 (MFP 6/52)
3167-PHILA-51 (s/n 405)  2 tags speaker jack no # 4551 (MFP 8/52)
3167-P-51-01-C (s/n 710)  2 tags speaker jack no # 6016 Hallicrafters manual and cabinet
3357-PHILA-52 (s/n C 25)  1 tag switch - FC? no strange tag s/n - # 6707
3357-PHILA-52 (s/n 14)  2 tags speaker jack no # 5595 (MFP 12/52)
3357-PHILA-52 (s/n 82)  ? switch - FC? no once used in Naval Reserve
3357-PHILA-52 (s/n 95)  2 tags switch- FC no # 6300 (USN and anchor inspection stamps)  1952-53 component dates
3357-PHILA-52 (s/n 98)  2 tags speaker jack no # 5645 (MFP 12/52)
3357-PHILA-52 (s/n 230)  2 tags speaker jack no # 5749
3362-PHILA-52 (s/n 109)  1 tag speaker jack yes - FC Burlington # 6168 (with add-on mech. filter kit)
photos
3362-PHILA-52 (s/n 180)  1 tag speaker jack no # 6363
3362-PHILA-52 (s/n 182)  1 tag speaker jack no   -
3362-PHILA-52 (s/n 225)  1 tag speaker jack no # 6405
3469-PHILA-52 (s/n 140)  1 tag speaker jack no # 5313
3470-PHILA-52 (s/n 1437)  2 tags speaker jack no # 5564 (MFP 12/52)
(USN & Signal Corps inspection stamps)
25067-PH-54-55 (s/n 61)  1 tag speaker jack no   -
25635-PHILA-53-36 (s/n 135)  1 tag switch- factory no # 6840 (note - has 3 tags - MWO and CAUTION tags added later and held on by only 2 screws each)
25635-PHILA-53-36 (s/n 351)  1 tag switch- factory no # 7056
25635-PHILA-53-36 (s/n 445)  1 tag switch- factory no # 7150
25635-PHILA-53-36 (s/n 558)  1 tag switch- factory no -
25635-PHILA-53-36 (s/n 610)  1 tag switch- factory no # 7135
25635-PHILA-53-36 (s/n 719)  2 tags switch- factory no MFP Aug 1964 (??)
25635-PHILA-53-36 (s/n 861)  1 tag switch- factory no # 7536
25635-PHILA-53-36 (s/n 1xxx)  1 tag switch- factory no Burlington  photos
25635-PHILA-53-36 (s/n 1292)  1 tag switch- factory no # 7997
25635-PHILA-53-36 (s/n 1319)  1 tag speaker jack? no # 8024
25635-PHILA-53-36 (s/n 1647)  1 tag switch- factory no -
25635-PHILA-53-36 (s/n 1881)  1 tag switch- factory no # 8637
25635-PHILA-53-36 (s/n 2072)  1 tag switch- factory no # 8778
25635-PHILA-53-36 (s/n 2256)  1 tag switch- factory no Burlington  photos
25635-PHILA-53-36  1 tag switch- factory no Burlington  photos
25635-PHILA-53-36  1 tag switch- factory no DeJUR  photo
25635-PHILA-53-36  1 tag switch- factory no -
25635-PHILA-53-36  1 tag switch- factory no -
25635-PHILA-53-36  1 tag switch- factory no -
25635-PHILA-53-36  1 tag switch- factory no -
25067-PH-54-55 (s/n 140)  1 tag switch- factory no Burlington  "140" ink stamp on rear
25067-PH-54-55 (s/n 242)  1 tag switch- factory no  "242" ink stamp on rear
25067-PH-54-55 (s/n 327)  1 tag switch- factory no  "533" on rear
25067-PH-54-55   1 tag switch- factory no -
21318-PH-56 (s/n 28)  1 tag switch- factory no "28" stamped in metal on rear
21318-PH-56 (s/n 72)  1 tag switch- factory no 6/56 inspection stamp
"72" stamped in metal on rear
21318-PH-56 (s/n 101)  ?  ? ? ?
21318-PH-56 (s/n 113)  1 tag switch- factory no  "444" ink stamp on rear
21318-PH-56 (s/n 138)  1 tag switch-factory no  "138" stamped in metal on rear
30951-PH-57 (s/n 58)  1 tag switch- factory no Burlington?  photos
30951-PH-57 (s/n 67)  1 tag switch- factory yes - FC Simpson "67" stamped in metal on rear
30951-PH-57 (s/n 193)  1 tag switch- factory yes - FC? Simpson  photos
30951-PH-57 (s/n 211)  1 tag switch- factory  ? Simpson  photos
30951-PH-57 (s/n ??)  1 tag switch- factory  yes - FC? Simpson  photo - more photos
37003-PC-62 (s/n 95)  1 tag switch- factory  yes -
37003-PC-62 (s/n 107)  1 tag switch- factory  yes -
37003-PC-62 (s/n 145)  1 tag switch- factory  yes -
37003-PC-62 (s/n 168)  1 tag switch- factory  yes "0035" ink stamp on rear
FCC part 15 compliance stamp
37003-PC-62 (s/n 294)  1 tag switch- factory  yes FCC part 15 compliance stamp
37003-PC-62 (s/n 300)  1 tag switch- factory  yes no Collins production # on rear
Signal Corps - unknown contract - - - -
(Signal Corps) ???  1 tag speaker jack  ? (I can't read contract number)
(Signal Corps) ???  1 tag speaker jack  ? (I can't read contract number)
 (Signal Corps) ???  1 tag speaker jack  ? (I can't read contract number)
(Signal Corps) ???  1 tag speaker jack  ? (I can't read contract number)
(Signal Corps) ???  1 tag speaker jack  ? (I can't read contract number)
(Signal Corps) ???  1 tag switch- factory  ? (I can't read contract number)
(Signal Corps) ???  2 tags speaker jack ? (I can't read contract number)
(Signal Corps) ???  2 tags switch- FC  ? (I can't read contract number)
(Signal Corps) ???  2 tags switch- FC  ? (I can't read contract number)
*** this one had a U(anchor)S stamp where the tag would have been
      - but overlaying part of the anchor stamp was a red SC triangle
      - meaning it was Navy first and Signal Corps later? - how's that for a mystery????

R-388 Listed by Collins production serial number (with contract when known)

production # stamped in rear
(Contract Number)
ID tag holes Break-In Switch
or Speaker Jack?
AGC/Diode jacks on rear? Other Info
#   28  ( 21318-PH-56)  1 tag switch no late production
#   72  ( 21318-PH-56)  1 tag switch no late production - 6/56 inspection stamp
#   129  (21318-PH-56?)  1 tag switch no late production MFP 7/56
#   138  (21318-PH-56)  1 tag switch no late production
#   235 (19624-PHILA-50)  1 tag speaker jack no  MFP 7/51
#   267 (19624-PHILA-50)  1 tag speaker jack no   -
#   445  1 tag speaker jack no MFP 8/51 - has USN anchor stamp overlaid by Signal Corps stamp
#   446 (19624-PHILA-50)  1 tag switch- FC no  -
# 1072 (1908-PHILA-51)  2 tags speaker jack no MFP 10/51
# 1196 (NObsr-52527)  1 tag speaker jack no MFP 11/51
# 1404 (3131-PHILA-51)  2 tags speaker jack no - TEST jack no MFP
# 1542 (3131-PHILA-51)  2 tags speaker jack no MFP 12/51
# 1575 (3131-PHILA-51)  2 tags speaker jack no MFP 12/51
# 1769 (TCG-38466)  1 tag speaker jack no MFP 1/52
# 2002  1 tag speaker jack no MFP 11/52
# 2076 (51J-3)  ? ? ? Delivered 3/53
# 2090 (51J-3)  ? ? ? Manuf 1/53, MFP 1/53
# 2207  1 tag speaker jack no 1953
# 2618   1 tag speaker jack no with add-on mech. filter kit
# 2818   1 tag switch- FC no MFP 3/52 anchor stamp
# 3109 (3131-PHILA-51)  2 tags switch - FC no switch added and front panel refinished per MWO SIG 11-264A-1 for AN/GRC-26A (1953)
# 3293  1 tag  speaker jack no has mech. filters added
USN and Signal Corps stamps
MFP 9/52
# 3353 (3096-PHILA-51)  1 tag speaker jack no MFP 9/52
# 3517 (3167-PHILA-51)  2 tags speaker jack no MFP 6/52
# 3849   1 tag switch - FC no MFP 6/52 with signal corps marks
# 3914   1 tag speaker jack no MFP 9/52
# 4009 (3164-PHILA-51)  2 tags speaker jack no MFP 7/52 anchor stamp
# 4134 (3135-PHILA-51)  2 tags speaker jack no MFP 7/52
# 4139  2 tags speaker jack no MFP 7/52 anchor stamps on sides
# 4214 (3164-PHILA-51)  2 tags speaker jack no MFP 7/52
# 4229 (NObsr-52527)  1 tag speaker jack no   -
# 4323  2 tags speaker jack no  MFP 8/64 - why so late?
# 4551 (3167-PHILA-51)  2 tags speaker jack no MFP 8/52
# 4582  2 tags speaker jack no MFP 8/52
# 4622 (3167-PHILA-51)  2 tags speaker jack no MFP 8/52
# 4703  2 tags speaker jack no MFP 9/52 "4703" stamp on rear and under ID tag
with CY-1260/G cabinet
has anchor stamp on side panel
# 4823 (NObsr-52527)  1 tag speaker jack no  -
# 4930   2 tags speaker jack no MFP 9/52
# 5313 (3469-PHILA-52)  1 tag speaker jack no -
# 5373 (?)  1 tag speaker jack no MFP 10/52
# 5462 (NObsr-52527 )  1 tag speaker jack no MFP 11/52
# 5480 (NObsr-52527 )  1 tag speaker jack no MFP 11/52
# 5564 (3470-PHILA-52)  2 tags speaker jack no MFP 12/52
# 5595 (3357-PHILA-52)  2 tags speaker jack no MFP 12/52
# 5645 (3357-PHILA-52)  2 tags speaker jack no MFP 12/52
# 5677   2 tags speaker jack no  -
# 5749 (3357-PHILA-52)  2 tags speaker jack no -
# 5810 (3164-PHILA-51)  2 tags speaker jack no USN and anchor inspection stamps
# 5926  2 tags speaker jack no -
# 6016 (3167-P-51-01-C)  2 tags speaker jack no Hallicrafters CY-1260/G cabinet and manual
# 6027 (51J-3)  1 tag speaker jack no MFP
# 6109  1 tag switch - FC no USN and anchor inspection stamps
# 6168 (3362-PHILA-52)  1 tag speaker jack yes   -
# 6300  (3357-PHILA-52)  2 tags switch- FC no (Signal Corps tags but with USN and anchor inspection stamps) 1952-53 component dates
# 6314    2 tags switch-FC no anchor inspection stamps
# 6363 (3362-PHILA-52)  1 tag speaker jack no -
# 6405 (3362-PHILA-52)  1 tag speaker jack no -
# 6594  ? speaker jack   -
# 6626   1 tag speaker jack no   -
# 6707 (3357-PHILA-52)  1 tag switch-FC no strange contract serial "C 25"
# 6730  1 tag switch-factory no -
# 6840 (25635-PHILA-53-36)  1 tag switch-factory no   -
# 7056 (25635-PHILA-53-36)  1 tag switch-factory no -
# 7135 (25635-PHILA-53-36)  1 tag switch-factory no -
# 7150 (25635-PHILA-53-36)  1 tag switch-factory no -
# 7532 (1908-PHILA-51)  1 tag switch-factory no 1953 DATE CODES
# 7536 (25635-PHILA-53-36)  1 tag switch-factory no -
# 7997 (25635-PHILA-53-36)  1 tag switch-factory no -
# 8024 (25635-PHILA-53-36)  1 tag  speaker jack no -
# 8200  1 tag  speaker jack no -
# 8386 (1908-PHILA-51)  1 tag switch-factory no s/n seems late for contract?
# 8465 (1908-PHILA-51)  1 tag switch-FC no s/n seems late for contract?
# 8637 (25635-PHILA-53-36)  1 tag switch-factory no -
# 8756 (1908-PHILA-51)  1 tag switch-factory no s/n seems late for contract?
# 8771 (NObsr-52527)  1 tag switch-factory? no s/n seems late for contract?
# 8778 (25635-PHILA-53-36)  1 tag switch-factory no -
# 9151 (USAF R-645/GPQ-3)  1 tag speaker jack no Blue front, no handles
No ID - - -   - 
???  2 tags speaker jack no  (MFP 1964)
???  2 tags speaker jack ? -
???  1 tag speaker jack ? -
???  1 tag switch- factory no -

51J-4  Data Base - please send me more info
  - note no R-388A/URR tags seen yet
  - units appear to be commercial, not military - only a few with MFP treatment
  - what's with the FCC Part 15 compliance stamp?
  - Click here for black 51J-4 mystery photos

Contract ID tags Break-In switch? Diode/AGC jacks
on rear
FCC part 15 compliance stamp Notes
51J-4 (s/n 16) 1 tag  speaker jack no no "16" ink stamped on rear, MFP
51J-4 (s/n 36) 1 tag  speaker jack no no "36" ink stamped on rear, MFP
1-53 date code on filter cap
51J-4 (s/n 53) 1 tag  speaker jack no no "343" ink stamped on rear
unusual Collins ID tag - photo
51J-4 (s/n 105) 1 tag  speaker jack yes yes "048" ink stamped on rear
Collins gray-front test unit
51J-4 (s/n 125) 1 tag  speaker jack no no -
51J-4A (s/n 207) 1 tag  speaker jack no no "225" stamped into metal on rear
Made for Westrex - photos
51J-4 (s/n 505) 1 tag  speaker jack no no "505" ink stamped on rear
51J-4 (s/n 814) 1 tag  speaker jack no no -
51J-4 (s/n 952) 1 tag  speaker jack no no "952" ink stamped on rear
51J-4 (s/n 1062) 1 tag  speaker jack no no -
51J-4 1 tag  speaker jack yes yes "165" ink stamped on rear
51J-4 1 tag  speaker jack yes yes "457" ink stamped on rear
51J-4 (s/n 1979) 1 tag  speaker jack yes yes "1979" ink stamped on rear
51J-4 (s/n 3516) 1 tag  speaker jack yes yes "199" ink stamped on rear - photos
51J-4 (s/n 5360) 1 tag  speaker jack yes ? 1960 date
51J-4 (s/n 5501) 1 tag  speaker jack yes ? "30" ink stamped on rear
51J-4 (s/n 5928) 1 tag  speaker jack yes yes -
51J-4 (s/n 5987)  ?  ? ? ? -
51J-4 (s/n 7021) 1 tag  speaker jack yes yes S-line knobs 
51J-4 (s/n 7263) 1 tag  speaker jack yes yes S-line knobs  - photos
51J-4 1 tag  speaker jack yes yes -
51J-4 1 tag  speaker jack yes yes -
51J-4 1 tag  speaker jack yes yes -
51J-4 1 tag  speaker jack yes yes -
51J-4 1 tag  speaker jack yes yes -
51J-4 1 tag  speaker jack yes yes  - photos
51J-4 1 tag  speaker jack yes ?  - photos
51J-4 1 tag  speaker jack ?? ? -
51J-4 1 tag  speaker jack ?? ? -
51J-4 (gray panel) 1 tag  speaker jack yes yes -
51J-4 (gray panel) 1 tag  speaker jack yes yes -
51J-4 (gray panel) 1 tag  speaker jack yes yes -

Here's a story from W4OKW about R-388's used in Navy service.

   "I was enjoying a couple of days off in Athens and after seeing the Parthenon, etc, managed to find myself in an incredible flea market area quite close to downtown. Much to my surprise there were a number of electronic stores including some that were devoted to surplus, mostly US stuff.  Way in the back of one store was a pile of R-388s that made me think I had stumbled into "Fair Radio East"!
   Most of these were in pretty sad shape, having been "de-milled", but probably salvageable.  Some had missing meters, no tubes, but no outright ball peen hammer damage, i.e., the dials and knobs still turned reasonably easily.  The owner of the store was a ham and said that he had resurrected a couple by combining parts and they were nice receivers (I think the kids would say "Duh!" at this point).
    He claimed that the receivers came from the NAVCOMMSTA at Nea Makri and the USAF station at Helinikon AB near Athens, as well as the San Vito/Brindisi Italy stations.  They were all "spook" stations, so I am sure were involved in surveillance somehow.  
   I did see a couple at the Weather Det. at Rota, Spain being used for HF Weather Fax links.  They had the nicest field of Rhombics and Log Periodics at Rota in a field across the runway from the hangars and base proper.  They had HF links from Rota to Sig to Nea Makri, etc.
    I still regret not buying a bunch of them and sticking in the C-130 for the ride home to Rota!  Boatanchors were just so much junk to me in those days!"

Major mystery questions