Screen turning black and white sometimes?

i don't know if its some kind of capacitor overheating or something but sometimes when i turn it on it has color for about 10 minutes before it turn black and white and when i unplug and replug same thing. i have to turn it off for a long period of time and turn it on and its back to normal which made me think it might be something overheating but then a strange thing happened.. where while it was on and black and white and turned into color. which now makes me think that it might not be an overheating component? idk maybe someone can help me. its a Sonya C1461TX-C and im use a Nedis HDMI in - SCART out converter box VCON3461BK to connect it to my pc. i am from europe and do use the pal setting and everything so is the tv.