GE TV 13GP241/ TX826TB Cycling Problem

I have a GE TV model 13GP241 with a TX826TB chassis
The problem I am having is when the set powers up, after 2 or 3 seconds
it starts cycling on & off continiously.

I have no schematics for this set & its not really a cost effective
repair if I have to spend hours trouble shooting to find the problem.

I have soldered alot of cold solder joints I spotted but that made no
diference.
Does any one have any ideas on what is causing this or what I should
check ?

Thanks in advance, Roger

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