tdiaz@apple2.info wrote:
If it's one of the primary colors getting brighter, (Red, Green or Blue), then the problem is on the neck PCB. If I had a picture of the PCB I can spot the component, but if you look at the schematic that issue is in the vicinity of Q601, Q602, or Q607. Either that transistor is opening up and allowing full voltage through or the associated diode is doing so.
It's every color which gets brighter. Everything. I can take some photos if you're interested in seeing. The effect is as if I turned every brightness knob/pot up to its fullest. (Except that, obviously, I'm not)