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Later Leslie motors have a sticker on them indicating their manufacturing date.The formula is XXX-YYWW, where XXX is the manufacturer EIA code (190 indicates General Instrument in the present example), YY is the last two digits of the year of manufacture, and WW is the week of manufacture.Some of the entries on the age list show actual known production dates and can be used as markers to guage the quality of other entries around them.Until this work is published, the Age List will continue to function more or less as it has; a quasi-definitive source of this information and a registry of Hammond and Leslie product owners.To help determine the manufacturing date of Hammond organs and Leslie speakers.Use this form if you would like to submit your Hammond Organ for inclusion in these tables.
Please include an email address so I can contact you if I have a question. With a production history covering more than forty years, determining the exact manufacturing date of tonewheel Hammonds used to be difficult; new models were not introduced every year and production changes that were made were often subtle.Thanks to the Electronics Industry Association (EIA) code conveniently placed on them by the manufacturer, many individual components can be dated to the year and week of production.Due to Hammond and Leslie purchasing components in large quantities, using these codes as definitive signposts will not produce an accurate "born on" date.3227204 is a Tung-Sol tube manufactured during the fourth week of 1972.
Tung-Sol 6550 tubes made for other companies (like RCA) have a four-digit date code only.Even the above is fraught with some risk, as replacement parts used for repair or modification will occasionally skew the overall picture.