The picture is to big for the screen it doesnt

if you are using a cable box you must go to settings on your cable box and zoom out there is an option not sure where its located on which cable box your using . If the tv is hooked directly to the cable outlet itself its a menu option on your tv there is a zoom option and some remotes also have a zoom botton.

The replacement picture tube new "if available" would cost more than a new set, unless you are lucky enough to find a good used one. but it sounds like the shadow mask inside the original tube has shifted, not sure how effective degaussing will be.

Is this the actual model # AV-32F475?
If so, sounds like you have a shorted color filament within the picture tube. Could also be a video output going bad, causing intermittent shutdown when the CRT's beam current reached overload.

No sound coming out from my jvc av-48p575.

Is your cable bill paid, I know that some cable companies could lock your tv if you are in arrears. I hope this is not it...

I usualy fix broken boards but if the crack is around a very small circuit traces it will be almost impossible to fix it.

most likely a sync problem

The black box is called a text box and it is a selection in the
closed caption feature or CC......go thru each menu page until
you find CC....cycle thru choices until you get to off or try each selection until Text box and CC are off.................T.

try unplugging for a few seconds the plug it back in

it sounds like a pin-cussion correction circuit failure. A tricky circuit to troubleshoot even for an experienced tech. check servicemanuals.net for info