The lack of sound and raster might be a fairly simple thing, bad fusible resistor as suggested, bad LV rectifier, (can't remember what that is on a Predicta)
Chances are though once you get it lit it will still need recapped to produce anything watchable.
You can get some idea of what you're in for by looking at Phils Old Radios page, his is a floor model but the chassis is similar.
http://antiqueradio.org/philc12.htm