Easy stuff forst.
Dark left, bright right is a classic across all brands. Follow the 200V
supply for the 3 color outputs. You will find a rectifier off the FBT
& a little electrolytic for a filter. Change the cap. Typical is 4.7mfd or 10mfd. Use a 350 volt or more.
Pin problem on smaller sonys this era is a small electrolytic off the pin
amp control IIIRC. Common problem.
BTW remember that cap on ANY brand TV. It causes one or more of the
following.
Dark to brite across the screen
Jail bars
smearing
Retrace lines
bright white then sometimes HVSD
Poor "not right" pix
Can fool yoy into thinking bad CRT !
And probably some I forgot
73 Zeno
LFOD !