Then 134-6320 would become 134-320 and the specifications of the instrument should be used for determining the approximate year or decade the particular instrument was built.
Here is a brief listing of the manufacturers Source Code numbers: 34 – Cornell-Dubilier Electronics (made capacitors used on early Fender Guitars and are the ones that were paper and wax coated.
They now make polyester film capacitors) 106 – Allen-Bradley Corp.
(Make potentiometers and from El Paso, Texas) 117- Credence Speakers, Inc (Kevil, Kentucky) 124- Alpha Wire Corp. You can find old spools of wire and see codes and dates on the reels) 134- Mepco/Centra Lab, Inc. Philips Corp.) 137- CTS Corporation (made amplifier and instrument potentiometers and are based in Elkhart, Indiana) 140- Clarostat Mfg. (made pots for early Fenders and had code stamped in blue ink) 145- Illinoise Capacitor, Inc.
If the code does not fit the above criteria, don’t force it and skew your dating results.
Part Number: 137-8916 10k Date Code: AH9715 Manufacturer: CTS This 10 turn “BALL POT” 10K Ohm panel mount Potentiometer has a 1/4″ diameter shaft 3/8″ long with a threaded bushing 3/8-32 thread 3/8″ long and wire solder terminals for instrumentation controls. The multi-turn feature allows for accurate setting of the Potentiometer.
This is information from the Engineering and Publications department.
In addition to a source code, it may be desired to identify the date of production.
When dating an instrument by the ‘pot code,’ keep two things in mind: The potentiometers must be original to the piece (new solder, or a date code that is off by ten or more years is a good giveaway to spot replacement pots); and the pot code only indicates when the potentiometer was manufactured!
The codes were created by the Electronic Industries Association (EIA) in 1920s to identify the product source and date of manufacture.
The first string of numbers is usually the part number, or sometimes the pot value.
The diameter of the POT is 1″ and the depth behind the bushing is 5/8″.
It comes with 2 standard 3/8-32 nuts and is packaged in lots of 10 units per bag.