Facing TV Problems? Ask a TV Technician.
Hello, The set cycling only "OFF" is an issue with the power supply capacitors. However the set cycling OFF and back "ON"- is caused by the Mainboard (this is even documented in Samsung's service notes). The Mainboard contains the EEPROM and produces the power supply on and off commands. In order to fix this you would need to replace the Mainboard- which is the board with the AV and HDMI jacks located on it.
Feel free to reply back if you need more help, or want to reply back with more details. It does not cost you anything more to reply back once you've rated. Please do rate me positively (at least 3 STARS) and I will continue with you until this is sorted. The positive rating ensures I am credited for my work.
What level tech are you, and do you have an IC extractor? The EEPROM is a many pin surface mount component- not something easily replaced.
Okay, I don't personally repair these boards down to a component level I board swap, so I won't be of too much help here, and I've seen many techs chase their tails trying to repair a Mainboard. I will have to opt out on this one I'm afraid.