For what it is worth, here is my experience....I put a circuit board from a computer monitor (whose BGA re-scaler chip lost good electrical connection) in my kitchen oven at 375F for 8 minutes. After re-install, the original screen blinking problem went away. (for 2+ months so far!) No preheat of board/chip, I just turned on the oven and when it hit 375F, I put my board in and waited 8 minutes. I removed the board and let it cool down before re-installing. No reballing. Pretty crude, but it worked.
Anectdote...The problem was caused by the large amount of heat generated by the monitor's built in power supply. It is a 30 inch monitor, so it generated a lot of heat. I left the back cover of the monitor off, so the heat now easily escapes. Others who reflowed their scaler chips in the kitchen oven, but put the monitor back cover back on had their re-scaler chip separate again. I also put a heat sink in the rescaler chip (with double sided thermal tape) and attached a usb powered fan. The heat sink doesn't even get warm, so I think it is probably unnecessary. Just leaving the cover off (faces the wall) seems to have solved the problem.