I would like to know if you can help me whit this issue.
I'm going to explain the failure clearly so you can imagine which is
the problem. I have a KV-27TS27 TV Set, I recently repaired it from
the power supply. Everything is working fine except when the TV set
tunes a brighter image. When it happens, there's a loud hum in sound
and the edges of the image were wiped. When the image changes to a
darker scene the failure ends, an so on and on, (only whit brighter
images). I have noted that even in darker images or scenes the edges
of these images were slightly wiped.

Which is the cause of this failure?
Is there any aged components such as electrolytic caps causing the
trouble?
In which part of the TV set can I start to look for the trouble?
What can I do to fix it?

Please help me, I will be very grateful about your help.