My Samsung TV will turn itself off, 30 seconds later it will turn back on. Then the cable box will turn off, then on again after 15 seconds. There is then a blue screen that says "no single or weak single" then the blue screen begins a series of 5-15 strobe like flashes. Then the picture will return and everything will be fine until the next time (5min. - 2 hours). Cable people have been out 6-8 times and replaced the cable, the connectinons, and four different cable boxes, still the same results. I took off the back and sprayed everything with can air. There has been some improvement ( about 60% fewer times) but are still getting the same as before. I also looked at the capasitors and they were flat on top, so I don't think its them. I also have changed out the wall outlet and grounded that outlet. Still the same.

Borrow a small flat TV and see if it's the same. If it isn't the box, the cables (inside house and all the way outside to the pole, if you aren't in a city), or your house wiring - what's left? The TV. How old is yours?

Try blocking your IR detectors, do you have remote Ir's plugged in the back of the boxes. A Remote malfunctioning?