HI Melvin. It is hard to diagnose issues like that over the net. But my first suspicion would be the bandswitch, if so equipped. Contacts can get dirty. I just had a look at your radio's photo, and it looks to be the age of a set that would have a bandswitch.
If you are experienced at romoving the rear of the cabinet, you may be able to see the band switch. It is full of contacts. You can use a contact cleaner, (make SURE it is safe to use on plastics) spray a little on the wafer switch, the work it back and forth.
[img]
http://antiqueradios.com/gallery/d/109664-1/philco+band+1.JPG[/img] This is what a typical bandswitch looks like.
This is the most common reason a set will not pick up on some bands. Pushbutton operated radios is the next common cause of no reception on certain bands. I strongly doubt it would be from an open coil or other major issue.
Good luck an hope you get the set working.