Tv Issues

[howie789]

Well I bought a 27" (CRT)TV off Craigslist on the cheap..everything's OK except when I turn on the set, or within the first few minutes- the picture gets snowy, and I lose reception..the coaxial cable is on tight. I read where it could be a loose solder. I cant afford a repairman, but what are some non-technical remedies to prevent this from happening again -other than whacking it? or do I have to live with it...