27" (diagonal screen) Panasonic regular crt TV few years old, no serial # on front and too heavy for me to look at back.
Picture comes on great, then a grey (NOT BLACK) screen covers 99% of screen with a...
It will be good to check the capacitor on the +B voltage that goes to the power section in the main board. A filter capacitor of about 47mF/160 V can be defective.
Next check the capacitor on the HT line to the grid-22mf/250V replace.
If possible loop on capacitors in the horizontal section particulary the IC.
Now the tip I can offer:
If the fault occurs on heating shcek out htis area to confirm and isolate the component.
But finally I understand that when you press any key the picture is good.If so check the memory IC/cmos IC in this section for logic control, it might be having a switching fault, a conflict or the video noise is coming on in default but goes off in the data selection mode. Do a soldering around this section on the IC , capacitor and see if the fault goes off or becomes irregular when this section is heated, if so there is a semiconductor producing this noise error .
So start from the begining so that we have a clean voltage inside.
I hope my advice helps.
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