Before checking any other issue, verify the power cord is ok, and the
surge protector and outlet (electrically) is verified ok before proceeding
with further repairs. Especially check for bad electrical grounds. I usually
verify these things before cracking open the TV, because it is efficient
this way and saves time, in addition to ruling out some external cause
for creating an internal problem. Then think to the time of the failure of
the TV for a moment. Was there an unusual situation when it failed? Was
there a storm? Was there a brown out or black out? Anything else unusual?
Again, ruling out external causes relating to the internal problem you suspect
is on the TV.
If it is indeed a problem with the TV internally, then I would check with the
usual suspects, based upon the common failures or problems associated
with that model. Someone mentioned swollen capacitors, there's also power
supply issues, regulated B +, Invertor board issues, resistors, diodes, and
a plethora of the usual suspects in terms of other electronics components,
not to mention checking for bad solder joints, bad connections, etc...
There is a lot of time spent tracing problems out. Based upon the model,
I would hone in on the usual suspected causes of failure, then look for
the isolated cases to determine cause and efficiently provide for a more
pinpointed, accurate diagnosis. Consult the service manual and other
professionals for assistance. Use your tools and equipment effectively
and wisely to help provide for a solution to the problem.
Good luck.
Charles Lucas