help with an admiral

[jamie]

first off, i have very little knowledge about working on these sets or tvs in general but i have what i have been told is an 1955 Admiral CA2246. It comes on fine(takes a little while to come on though but i assume that's normal?) I hooked it to my cable with the 75 ohm antenna adapter but get no picture no matter what channel the set is on. I do get sound off what would be the local channels but no cable channel sound. I hooked it up to a vcr as well and still get no picture but do get sound. What should i check for first that causes no picture?