A little tangential to Apple IIs, but related. I have an Amdek Video S500 Amber CRT (always wanted one as a kid in the '80s).
It "works", but the image is soooooooo faded. Even with brightness and contrast turned up full, the image will be there for maybe 30 seconds, but very dim and then fade away.
Anyone ever fixed a CRT? Based on some Googling, I am suspecting the fly back transformer (is that the right name)?
I have opened it up and looked around. Nothing glaringly wrong. I have not gone as far as to ground/de-energize the CRT and start pulling wires (yes, I know, there is dangerous voltage. I was also hit by lightning when in the Army, soooooo I think I'm indestructable. ;-) )