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These are codes often seen stamped on components found in US made vintage tube equipment. This list is circa 1955, and some codes have been reassigned or added since that time.

Code formats were not completely standardized, but a little deciphering will generally yield the info of interest. Note that many makers also stamped OEM (Original Eqipment Manufacturer) part numbers above or below the EIA code, in some cases parts makers or the customer elected not to include the EIA codes, so not all parts have them.

They generally follow the following format: (example)

322 5904

where 322 is the manufacturer code (in this case Tungsol), 59 is the year (1959), and 04 is the week.

One alternate scheme is:

274 940

274 is the EIA code (RCA) 9 is the last digit of the year (in this case 1949). Usually single digit date codes are from the 1940's, but have on occasion shown up in later decades, even up to the 1970's. If one has a general idea of the age of the piece in question, usually the decade can be divined from that.

Another alternate is in the format following:

188-5 69 32

188 is General Electric. 5 is the plant code (in this case, Owensboro, Kentucky). 69 32 is 1969, 32nd week.

And another is like this:

322 6104-1

322 is Tungsol, 6104 is 1961, 4th week, 1 is the shift code (1 would probably be the day shift)

After about 1960, many tube manufacturers went to encrypted alphabetical date codes., such as:

KE

188-5

The reason was purportedly to allow factories to track the dates of manufacture of defective tubes (especially important in the case of OEM customers that might send back entire batches of tubes), but avoid possible consumer complaints about "stale" tubes. This sounds perhaps a little silly since the shelf life of tubes is decades, at least (indefinite in practical terms), but some OEM's might have beenn a bit irritated by occasional consumer complaints such as "my 1961 model TV has 1959 model tubes in it!"

Tubes made for the US military, or certain OEMs (such as some test equipment manufacturers) that requested it, continued to carry numerical date codes.

In years past, EIA (Electronic Industries Association) also went by the name of RETMA, and the original acronym of RMA (Radio Manufacturer's Association).
EIA Code Lists for:
Tubes
Capacitors
Transformers
Potentiometers (controls) & Resistors
Speakers
Other Manufacturers
 
Tubes and CRT's EIA code
Amperex (USA)  111
Bendix 125
DuMont 158
Eimac (Eitel-McCullough, Inc) 162
Electronic Tube Corp 169
General Electric Co (USA) 188
Hytron (CBS-Hytron) 210
Machlett 231
RCA (Radio Corp of America) 274
Raytheon 280
Superior Tube Co 310
Sylvania (Hygrade Sylvania Corp) 312
Tung-Sol 322
United Electronics 323
Western Electric 336
Westinghouse 337
Zenith Radio Corp (CRT's) 343
Nortn American Philips Corp 423
Taylor (aka Cetron-Taylor) 713
Lewis & Kaufman 738
National Electronics (also Cetron) 749
Penta Laboratories 771
Vacuum Tube Products 781
Varian Associates 809
Litton Industries 879
Electrons, Inc 935
Capacitors EIA code
Aerovox Corp 102
American Condensor  109
Centralab 134
Chicago Condensor 135
Aerovox Hi-Q Division 163
John E Fast 178
General Electric 188
Mallory 235
Micamold 240
Millen 242
Radio Condensor Company 273
Solar 296
Sprague 303
Gudeman 438
Good-All 446
Barker & Wiiliamson 461
Pyramid 472
United Condensor  516
Electrical Utilities Corp 569
Illinois Capacitor (Condensor) 616
American Radionic 648
Sangamo 658
Ajax 705
Standard Condensor  710
RMC (Radio Materials Corp) 732
Condensor Manufacturers 885
Transformers & Coils EIA code
Stancor (Chicago-Standard) 138
Coil Engineering 141
Ensign Coil 172
Freed  183
General Radio 194
Jefferson Electric 218
Thordarsen-Meissner 238
Merit Coil & Transformer 239
Standard Coil 305
Essex (Transformer Division) 352
New York Transformer 366
Altec Lansing-Peerless 391
Foster Transformer 394
General Transformer 412
United Transformer Corp (UTC) 418
Radio-Television Products Corp 489
Empire Coil 452
Caledonia 503
Triwec Transformer 524
Midwest Coil & Transformer 549
Standard Winding Co 550
F & V Coil Winding 572
Woodward-Schumacher 606
Central Coil 637
Electrical Windings 682
Grand Transformers 757
Forest Electric 773
Ogden Coil & Transformer 776
Triad  830
Better Coil & Transformer 831
Acro Products (Acrosound) 878
Mohawk 883
American Transformer 892
Tresco 897
Coilcraft 906
Aerocoil 908
Acme Coil & Transformer 928
Magnetic Coil Mfring 933
Northlake 1005
Pacific 1052

 
Resistor & Potentiometers EIA code
Allen-Bradley 106
Centralab 134
CTS (Chicago Telephone Supply) 137
Clarostat 140
Erie 173
IRC (International Resistance Co) 214
Mallory 235
Muter 244
Ohmite 251
Speer 300
Stackpole 304
Ward Leonard 532
Milwaukee Resistor 722
Dale 816
Atlas 932
Speakers (Drivers only, not cabinets) EIA Code
CTS (Chicago Telephone Supply) 137
Jensen 220
Magnavox 232
DuKane (Operadio Corp) 252
Quam (Quam-Nichols) 270
Rola 285
Utah 328
Western Electric 336
Altec Lansing Corp 391
North American Philips (Norelco) 423
Oxford  465
Waldom Electronics 555
Electro-Voice 649
Russell Speaker Co 748
Quincy Speaker Mfr Corp 767
Klipsch 843
University 847
Oaktron 934

Other commonly seen manufacturers
 
Company Product Code
Admiral Corp TV's, Radios 101
Alpha Wire 733
Amphenol Sockets, plugs 554
ATR Vibrators 551
Anaconda Wire 547
Arvin Sears radios & TV's 248
Astatic Phono cartridges 345
Belden Wire 579
Bell Amps 708
Bogen Amps 589
BIC British imports 409
Cannon Connectors 440
Cinch Sockets, connectors 139
Collins Radio gear 439
Connector Corp Sockets, connectors 888
Consolidated Wire 607
Crosley Radios 152
Drake RF gear 851
DuKane (Operadio) Amps 252
Eby Sockets 160
Empire Phono cartridges 452
Essex Wire 175
Gates RF gear 187
General Cement Adhesives, Testor's paint 396
General Radio Test Equip 194
Hallicrafters  Ham & SW gear 199
Hammarlund Ham & SW gear 201
Harmon-Kardon Hi-fi gear 794
Hickok Test Equip 508
International Rectifier Semiconductors 845
Jackson Tube Testers 216
E F Johnson Sockets, ham xcvrs 222
Kester Solder 224
Keystone Hardware 699
Lenz Wire 228
Littelfuse Fuses 230
McIntosh Hifi gear 793
Methode Connectors 720
James Millen Sockets 242
Muntz Cheap TV's 772
National Co Ham & SW gear, hifi 245
Newcomb Amps 437
Packard Bell TV's radios computers 254
Philco Radios & TV's 260
Philmore Hardware 262
Pickering (Stanton) Phono cartridges 631
Pilot Hifi tuners & amps 264
Pioneer Cheap recievers 706
Precision (Grommes) Hifi & PA amps 871
Radio Craftsmen Hifi gear 275
J P Seeburg Jukeboxes 289
Shure Brothers Phono carts, mics 590
Mark Simpson (MASCO) PA Amps 295
Simpson Electric Meters 614
Sonotone Phono cartridges 787
Tetrad Phono cartridges 842
Triplett Test equipment 321
Wells-Gardner Monkey Wards radios 334
Weston Test Equipment 338
Zenith Radios & TV's 343

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