Could you please provide the model number found on the back of set ?
This bizzarre behaviour is the lamp, its reflector goes high resistance this causes the set to draw more current which trips the set the lamp cools and the cycle is repeated
Here is the manual to download which on page 39 explains how to replace the lamp
Here is where to purchase the lamp I would recommend the sony original but its your call here as their is a cheaper replacement
Sorry for delay had a work commitment
It doesnt because the sensor for the lamp is not reading it as being faulty it will only do this if the lamp fails altogether or sometimes when the lamp has well exceeded its lamp hours
Also outside of this the lamp has a life of about 2 years of normal use and should not be left any longer than this as its exceeding its life envelope and could damage the light engine