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The Set: Pete Deksnis's Site about the CT-100

Restoring a Vintage Color Television Set

 CT-100 Chassis and CRT

Serial Numbers

A task as trivial as assigning serial numbers takes on an ungainly demeanor in the heat of new production goals, processes, and deadlines. In the section titled Serial Numbers for 15GP22s All Over the Place, there is evidence of those problems that invariably arise when something new is put into production. Next, the speculative opus A Sibling’s Tale postulates how an early 1954 production CT-100 can wind up with a 15GP22 date code from the middle of 1954. But first, The B is for Bloomington discusses current CTC-2 serial number records.   –Pete



The B is for Bloomington


Serial numbers for the CTC-2 chassis used in the CT-100 apparently begin with 100 (B8000100). [This assumption is based on current data; no serial numbers between B8000000 and B8000099 have surfaced.]


There are three documented CTC-2 chassis numbers in this first (100–199) numerical boundary: 0162, 0173, and 0194.


Serial numbers for the CTC-2 chassis used in the CT-100 probably end around 4100 (B8004100). [Updated 6-27-2007. I have lowered the quantity from 4600 to 4100 based upon the set of known serial numbers.]


The highest reported CTC-2 serial number is 4019. Close rivals are 3801 and 3911.


A Sibling’s Tale

Along with CTC-2 donor chassis B8000173, restored chassis B8000194 is probably part of the second day’s production run. Unlike 0173, its younger sibling, which according to date codes probably completed its manufacturing cycle on schedule, chassis 0194 was sidelined in 1954, probably due to a temperamental (or perhaps unavailable) 15GP22.


Later that summer, near the end of CT-100 production, it seems 0194 was revisited and given rebuilt 15GP22 serial number IL2078 dated 4 30 (30th week of 1954). This time, chassis B8000194 did pass muster, got shipped out the door, and wound up in Texas.


Chassis B8000194 and its kin, B8000173, were separated until 2004 when they met again in, of all places, my living room in Asbury Park, New Jersey.


Serial Numbers for 15GP22s All Over the Place 


The terms rebuilt and rebuilding refer to work performed on a 15GP22 before its final installation in a new CT-100 at the Bloomington plant in 1954.


·      Usually, a serial number for a 15GP22 is located on a paper label glued to the funnel, but sometimes it is found on a band of paper around the base of a 15GP22. Some will also have the serial number etched inside the tube, and one can then crosscheck that internal serial number with the paper label.


·      There is no visible serial number inside rebuilt 15GP22 IL2078. So unlike some rebuilt 15GP22’s that were given a new serial number, IL2078 appears to be the only serial number assigned to this tube.


·      An early 15GP22 yields yet another variation. 15GP22 with date code 4 04 (4th week of 1954), was not rebuilt. Yet for some reason, the label on the funnel marked IK1273 was overwritten with the same number etched on its shadow mask and phosphor dot plate: 6255. A second 15GP22 has surfaced with similar serialization characteristics. It began life 4 17 (17th week of 1954) as IK1795, but was renumbered 10201.


These three variations are summarized in the table.













4 04


No evidence of rebuilding. IK1273 and 6255 identify the same CRT. 6255 is etched inside tube. Label overwritten with 6255.




4 17



Some evidence of rebuilding. IK1795 and 10201 identify the same CRT. 10201 is etched inside tube. Label overwritten with 10201.


4 30


Rebuilt tube with original number IL2078.


4 26


Rebuilt tube with new number IL6057. First label was peeled away and replaced with new IL6057 label.

[Table updated 6-27-2007; 10201 added.]


In conclusion, it seems that out-of-spec 15GP22’s were being rebuilt by RCA at least during the 26th to 30th weeks of 1954 and then installed in a backlog of CT-100’s. Some 15GP22’s were given a new serial number, some were not. Early 15GP22’s had serial numbers etched on their shadow mask and phosphor dot plates.