Did I get a dud PS3, or is just a dud T.V.?

I bought a PS3 from someone in my family that needed the money. When I hook it up to my tv, I get sound but no picture. I have tried 2 different tv’s but I get the same result. My tv’s are old standard tv’s and I think she had it hooked up to a high def tv, so I tried the reset where you hold the power button down until it beeps twice and there is no change. We have actually gotten a picture a couple of times but then it froze up, so I don’t know if it’s my tv or the ps3?!