CDawg
Well-known member
Looking for brand new never used GE 6550A. Must be stapled plates and a date code around 1970. Doesn't have to be that specific year but the closer the better. Not interested in 1980s versions.
Willing to buy singles, pairs, triplets, quads, etc.
GE Sandblasted Date Codes on Glass Tubes
The sand-blasted dot codes on glass tubes represent the actual date of manufacture. These began to be used in 1952. Between 1962 and 1964 the dots sometimes "don't make sense" otherwise, the series is well behaved.
dots1.png (9.16 KiB) Viewed 27206 times
The base matrix of three rows and five columns encompasses the “W’s”, three upper “C’s” and the “Y’s”. The abbreviation “U.S.A.” made its appearance in 1960. Small and large dots occasionally appear in the upper row demarked here by the letter “X”. It is not yet understood what these extra dots represent, and the dots in the “X” row do not always line up with the lower columns. The other letters are defined as follows:
C – This center “key” column of dots is always present. The lowest “C” was added in 1972 and used through 1981. After 1981, military dates or consumer warranty dates are needed to differentiate these from 1960s counterparts.
W – These dots represent the week of the year from one to fifty three. Binary notation is used, and one must add the dots to get the week. The pattern for counting is below.
dots2.png (6.65 KiB) Viewed 27206 times
Y – These dots represent the years. Add the numbers to get the last digit of the year. ”O” is odd decade (1950s and 1970s), “E” is even decade (1960s and 1980s).
Willing to buy singles, pairs, triplets, quads, etc.
GE Sandblasted Date Codes on Glass Tubes
The sand-blasted dot codes on glass tubes represent the actual date of manufacture. These began to be used in 1952. Between 1962 and 1964 the dots sometimes "don't make sense" otherwise, the series is well behaved.
dots1.png (9.16 KiB) Viewed 27206 times
The base matrix of three rows and five columns encompasses the “W’s”, three upper “C’s” and the “Y’s”. The abbreviation “U.S.A.” made its appearance in 1960. Small and large dots occasionally appear in the upper row demarked here by the letter “X”. It is not yet understood what these extra dots represent, and the dots in the “X” row do not always line up with the lower columns. The other letters are defined as follows:
C – This center “key” column of dots is always present. The lowest “C” was added in 1972 and used through 1981. After 1981, military dates or consumer warranty dates are needed to differentiate these from 1960s counterparts.
W – These dots represent the week of the year from one to fifty three. Binary notation is used, and one must add the dots to get the week. The pattern for counting is below.
dots2.png (6.65 KiB) Viewed 27206 times
Y – These dots represent the years. Add the numbers to get the last digit of the year. ”O” is odd decade (1950s and 1970s), “E” is even decade (1960s and 1980s).