If that hoz drive is the source it must be coming from somewhere &
getting passed along. Its a classic ring that refreshes every line.
A few things....
If you cut open a jungle IC you see its a PKG of many IC's. Each usually
has its own GND & VCC pins.
I would also look at the blanking circuit. I have seen resistors in Sharp
& others cause this. Go up in value.
Mr squirrel give good advice, If you give him some peanuts & sunflower
i am sure he will help you further !
When I get ambition I will pull the Sams so I can see everything at once
73 Zeno
LFOD !