To All- I wanted to share an article I have recently written for the New Mexico Radio Collectors Club in Albuquerque, New Mexico. Since we are collectively radio amateurs, some antique radio and classic amateur radio equipment enthusiasts, this may be helpful to you. Anyway enjoy the information below and your comments are certainly welcomed.
Bob WB5YYX Unraveling The Mystery of Source Date Codes or How One Can More Precisely Determine an Antique Radio's Age By Bob Scupp WB5YYX We obtain a new find antique radio and wish to know how old is it. What is the manufacturing date? One can look at any collector's guide and get the date production started. But how long was this model/chassis manufactured? Can we determine somehow more precisely the year is was produced? The answers to all of the previous questions are YES, YES and YES! Starting during the 1940's electronic component manufacturers begin printing Source Date Codes on their parts. Over the years they have grown from 5 digits to 6,7 and 8. The first three or four numbers are the manufacturer code (which company made this part). The last four digits tell us the precise week and year the component was manufactured. Is this helpful in determining an antique radio's age? You bet it does! Let's take a better look at how it works. I recently purchased some items at the Albuquerque Tailgate Swapfest on April 23. One of them was an Emerson model G-1705a Lifetimer II AM/Clock radio. It was not listed in my collector's guide to tell me the original production starting year. I queried the AWA and Nostalgic Air Internet message forums and asked if anyone could tell me the first production year. I also requested a copy of the schematic and parts list. One person answered and told me it was in Sams 615-6 issued February, 1963. Therefore the first year of production for this model was 1962. But how many years did Emerson manufacture this model number? In the scheme of things what specific year was the one I had made in? Was this asking too much? Apparently not. Another who responded gave me a hyperlink to research Source Date Codes on electronic components. It was there that it became clear to me how to unravel the mystery of Source Date Codes. The first three or four digits in the SDC tell who the manufacturer was. For example, any electronic component beginning with 106 is Allen-Bradley. A component beginning with 137 is CTS Chicago Telephone Supply. CTS was a major electronic component manufacturer and sub-contractor for many other companies including TRW. I remember while working at Electronic Parts Company in Albuquerque our line of TRW products. Many of their resistor products, such as trimmer potentiometers and variable potentiometers had CTS stamped on them. The stamped part number began with 137! Of course TRW had their own part number as well. I noticed on the Emerson G-1705a that the tone control had a 1376404 number series stamped on it's back. The 137 is the code for the manufacturer CTS (Chicago Telephone Supply). The 6404 is the code for manufacturing date of the fourth week of 1964. Since it would be highly unlikely that Emerson would have stocked parts for a year, I determined it's production during the year 1964! The speaker had a part number of 180263, but it turned our to be Emerson's part number not the SDC. By the way, the speaker according to Sams 615-6 was manufactured by Quam. Can this SDC system be used elsewhere? ABSOLUTELY YES! These electronic components are common to many other electronic devices such as guitar amplifiers, TV's, etc. The website on the Internet for reading these SDC 's is http://www.provide.net/~cfh/pots.html. Enjoy the ability to date electronic products through the Source Date Code system! I will follow-up this article with more Source Date Code research as it becomes available to me. -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.322 / Virus Database: 267.3.1 - Release Date: 5/31/2005
