This indicates the power supply is not getting the proper feedback from related boards - or the power supply, itself is damaged.
Not having any history on the TV may turn out to cause additional monies being spent to get an actual "repair" - as the power supply failed for a reason - either from an outside issue (power surge, power outage, power spike, etc) or an internal parts failure which is causing the power supply to shut down.
Throwing money blindly (without proper testing and equipment) at the TV for repair is not advised - as you will have spent more than simply taking it to a shop for diagnosis.
The power supply is $360 itself... plus labor. CLICK HERE
for the available parts. Likely why the set sat unrepaired.
There is not an end-user quick fix or simple fuse replacement.
You might try a cursory inspection and look for bulging or leaking capacitors on the power supply board. This would indicate at least PART of the problem.
A local shop will charge a small fee (usually 1 hour labor) to investigate and pinpoint the problem(s) then quote you a price. If you decide to repair - the small fee is credited toward the repair (as most of the work is already done).
The TV MIGHT be worth about $500 in today's market, and you will need to decide if a repair is cost effective. Since it was left behind - the previous ownres likely decided the repair was not.
Thanks!Warning: TV circuits are dangerous, make sure you follow all safety procedures. It is suggested you should have at least a little knowledge of electronics and the dangers associated before attempting any repairs without proper training. Electronics (especially TVs) contain potentially LETHAL amounts of electricity that must be completely and properly discharged before attempting or troubleshooting repairs.
If you decide to attempt a DIY repair - do it only if you have full and total confidence in yourself and your abilities, and understand the consequences of working in this type of environment un-trained.