Model Pro97 - the brightness changes from dark to bright after about
30 minutes, and will stay at this brightness until the set is turned off and let cool down. I have checke/ resoldered pretty much the entire power board for bad solder joints, etc. Tried using a heat gun to find the problem and nothing so far. Hoping someone in this group has seen a similiar problem and maybe direct me in right area. Thank as always group.
Have you tried cooling spray???
You should use both cooling spray and the heat gun to find the component. This definitely sounds like a thermo sensitive component.
Changing brightness would obviously be in the CRT bias or in the blanking circuits. It is also possible to be a fault in the HV multiplier. I have had that module go defective in some TV sets causing your description.
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JANA _____
30 minutes, and will stay at this brightness until the set is turned off and let cool down. I have checke/ resoldered pretty much the entire power board for bad solder joints, etc. Tried using a heat gun to find the problem and nothing so far. Hoping someone in this group has seen a similiar problem and maybe direct me in right area. Thank as always group.ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.