Shuts off every 5 to 15 mins and blinks 7 times - cleaning vents didnt help - what should I replace ?

Open the front end of the blower.
You will find tow filters that slide out.
Clean them with water and replays them.

Go to the outside one, take a hosepipe and run a strong stream of water thru the radiator until its clean.

This will solve your problem.

Good luck.

Try the instructions listed at this site. If the problem still occurs after the reset it is usually the heater element that might be faulty.

http://www.appliancerepairlesson.com/dishwasher-2/dishwasher-clean-light-blinking-7-times/

Copy following link to troubleshoot by type of gas control valve, including directions for cleaning air intake screen, and or replacing gas control valve:
http://waterheatertimer.org/How-to-troubleshoot-gas-water-heater.html#intellivent
http://waterheatertimer.org/How-to-troubleshoot-gas-water-heater.html
http://www.thetankatwaterheaterrescue.com/forums/forum3/

7 flashes: Gas control valve might be bad.
4 flashes: FV overheat, clean air intake.
Soot indicates clogged air intake slowed combustion venting possibly causing overheating and lockout. Clean air intake screen located on bottom of unit.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Plasmas get hot, how long have you owned the unit, is it wall mounted or in some entertainment stand, make sure rear vents are clear and not full of dust, also make sure the cooling fans engage, you may have to pull rear cover off unit and get a can of compressed air and clean it out. I could not find on the web 4 blinking lights, I could find 7 and continuous... So 4 may mean something to company, is it under warranty, if so, call them up and schedule a repair.

check your sleep mode...

Common problem.
You probably need to clean
your dryer vent. Dryer vents
should be cleaned every couple of years to
prevent them from being clogged with lint. You can check the air-flow by going outside where the vents terminate. What's probably happening is on sensor dry, there's a moister sensor that tells the machine to shut off when there's no moister. The hot is is being pushed back into the dryer and confusing the sensor. That's why it's working on timer dryer because that option bypasses the moisture sensor.

I'm pretty sure that's it. Good luck.

I WOULD LOOK FOR AN ELECTRICAL (IGNITION) SHUTDOWN,CHECK WHEN IT SHUTS DOWN WITH SPARK TESTER TO SEE IF IT IS FIRING.

It's overheating. That's why it works longer the first time and you have to wait a few minutes for it to cool. Try using some compressed air and cleaning the vents out below. If that doesn't work then you'll have to remove and replace the thermal compound on the GPU and CPU.

do you have it conneting to the wall??? or threw something else???? be specific!!! it sounds like your power is not connected right!!! but explain to me in detail!!! check your connection from your ps3 or try cleaning the port from the connection!!