Hello everyone.
I found a dot matrix code following the part number or name in several tubes (mainly of the compactron kind but not exclusive). Mostly in newer units. Does anyone know what it mean?
It seems to be independent of the manufacturer (RCA, SYLVANIA, DELTRON).
I found a dot matrix code following the part number or name in several tubes (mainly of the compactron kind but not exclusive). Mostly in newer units. Does anyone know what it mean?
It seems to be independent of the manufacturer (RCA, SYLVANIA, DELTRON).
Attachments
The dot matrix codes were GE's method for identifying the date and place of manufacture of the tube. I have seen a site on the web somewhere that shows how to decode them, but I can't find it now. Some info is in the link below. It is used by GE exclusively, so it means that all the tubes you show were made by GE regardless of the actual brand on the tube. GE adopted this method sometime in the 1950's depending on who you talk to.
Each manufacturer also had an EIA code number. GE is 188 (often seen as 188-5, where the -5 is the place of manufacture). Sylvania is 312 and RCA is 274. Usually the EIA code, if printed on the tube will show who made it, but I have seen examples where this is incorrect.
GE uses the dot codes and the letters U.S.A. with the periods.
Sylvania uses the type number with USA (no periods) directly underneath the type number.
RCA puts the type number inside the familiar octagon "stop sign."
This applies only to US made tubes, and at least one Japanese manufacturer used a non symmetrical octagon for the type number (wider than it is tall).
https://www.antiqueradios.com/forums/viewtopic.php?f=19&t=230932
Each manufacturer also had an EIA code number. GE is 188 (often seen as 188-5, where the -5 is the place of manufacture). Sylvania is 312 and RCA is 274. Usually the EIA code, if printed on the tube will show who made it, but I have seen examples where this is incorrect.
GE uses the dot codes and the letters U.S.A. with the periods.
Sylvania uses the type number with USA (no periods) directly underneath the type number.
RCA puts the type number inside the familiar octagon "stop sign."
This applies only to US made tubes, and at least one Japanese manufacturer used a non symmetrical octagon for the type number (wider than it is tall).
https://www.antiqueradios.com/forums/viewtopic.php?f=19&t=230932
I had read the link and is quite intetesting.
The advantage is that the part number doesn't erase with time, that isn't true when simply painted.
Thank you again.
The advantage is that the part number doesn't erase with time, that isn't true when simply painted.
Thank you again.