Potentiometers Serial Numbers Lookup

DATING OF POTENTIOMETERS

In case the serial number of an electric guitar is absent or has become illegible, it is possible to estimate the age of the guitar by examining the potentiometers. These components feature a code that indicates the manufacturer as well as the year and week of production, which is referred to as the EIA code.

Where to find the EIA code?

The EIA code, consisting of six or seven digits, can be observed on the back or side of the potentiometer, either stamped or punched. The code includes the manufacturer code and the year/week code, with a possible space or dash in between.

By utilizing a potentiometers Serial Numbers decoder or dating system PROVIDED BELOW, it is possible to lookup information about the manufacturer and production date of an electric guitar’s potentiometer.

If the original potentiometers on a guitar are still intact and have not been replaced, it is possible to roughly determine the guitar’s production year using the EIA (Electronics Industry Association) code on the pots. This code provides information about the manufacturer and production date of the potentiometer.

However, it should be noted that this method only provides an approximation of the guitar’s production year since there is a period of time between the potentiometer’s production and its installation on the guitar.

This method is also useful for identifying the approximate production date of guitars from less well-known brands that do not have a serial number.

Read EIA code
With help of the EIA number on the potmeter, the production date can be determined. The first 3 digits on a pot are the manufacturer code.
The last 3 or 4 digits are the date code.
With 3 digits, the first digit is the last digit of the year, and the last digit is the week number.
With 4 digits, the first 2 digits are the last 2 digits of the year.

IRC (International Resistive Company) used a different date code system.
Example: 2144190500k627 is produced in July (week 27), 1956.

Not all manufacturers have or use an EIA code on the potentiometers.
For some series of CTS potentiometers, the full code can be entered in
the decoder and, in addition to the production date, the specifications
are also deciphered.

Example: 450GT79K504B2S1422
Serie: 450G Potmeter: 500 KΩ Tolerance: ± 20% Bushing Length: 19.1mm
Shaft Length: 28.6mm Torque: standaard Gemaakt: May, 2014
Manufacturer: CTS (Chicago Telephone Supply)

Based on the production date of the potentiometer, you can determine the approximate year of construction of the guitar.
The potentiometers are of course produced earlier than the guitar, and
in addition that there always have supply in storage.
Therefore, approximately 6 months must be added to the production date, but it remains an estimate.

Fender

In the 50s, in the Fender guitars and amplifiers, mainly potentiometers of the Stackpole brand were used.

From 1963, the switch was made to the CTS brand. To save costs,
a huge stock of CTS was bought in 1966 that was installed on the guitars until 1971. Guitars made until 1971 can therefore have potentiometers with the datacode of 1966. To save costs, a huge stock of CTS was bought in 1966

Gibson
The suppliers of pots at Gibson are (were) IRC, CTS, CentraLab
and CGE (with the Gibson logo).
IRC and CGE were used in the 1950s. Due to a fragile construction of the CGE potmeters (show rapid wear over time), Gibson has therefore switched to pots from CTS and later on CentraLab.

Höfner
Höfner guitars from before 1971 often do not have a serial number. You can read on the bottom of the pots of these guitars 128KΩ or 250KΩ with a 3-digit number. Here the first 2 digits are the week and the third digit is the year.

In some cases, the EIA code on the potentiometer may be obstructed by solder. If you have soldering experience, you can remove the solder using a solder sucker or desoldering braid. However, if you lack experience or confidence in soldering, it’s best to have someone else do it for you.

When removing the solder, it is recommended to use a soldering iron with a wattage of approximately 40 and a temperature of around 700°F / 370°C if using a soldering station. The soldering tip should preferably be of the chisel type since it can transfer heat more effectively than a pointed tip. Press the braid onto the tin that needs to be removed with the soldering iron and wait for it to absorb the tin.

After removing the solder, be sure to solder the connections back onto the potentiometer.

DECODER coming soon…

All decoders: