This article is from the comp.sys.ibm.pc.hardware.video Frequently Asked Questions, by Michael Scott with numerous contributions by others. (v1.0).
The sad fact is that even if you can obtain a new CRT, the cost to replace and make the needed color and geometry adjustments will likely be prohibitive. As noted in the section on Monitor Life - the CRT is the heart of the monitor, preserve it by turning the monitor off When not in use for an extended period of time. Screen savers do not help.
 
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