Thread: 21fb j p22
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Old 10-13-2023, 11:53 AM
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Quote:
Originally Posted by timmy View Post
So why is it that they say the red gun is very inefficient and seems to be the first gun to go in the 21fb j tubes. I would think that they have to put out even.
This has been discussed in various places on AK. The problem is not differences in the three guns but differences in the efficacy of the three phosphors. Red phosphors always had seriously less efficacy than green or blue until the rare-earth reds came along. This required the red gun to supply correspondingly higher current to get good color balance, hence the red gun would wear out first. When a rare earth tube was used to replace the tube in an older set, there was usually a service bulletin to change some resistor values in the video output so the three guns would be driven more equally.
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