Depending on the exact chassis check the 330 ohm resistor
on the bottom left of the 9-90 horz board. Replace with a
1 watt flameproof.
For snow try the RF AGC on 9-87 board. With a STRONG signal
adjust til the snow JUST clears up & you have no jitter.
As far as the S3 looking better it has an EFL CRT & will be brighter
& sharper. It may also have a comb filter which makes a huge
difference in resolution.
73 Zeno
LFOD !