What is wrong with my tuner?

Yesterday I bought a Realistic TM-101 solid state AM/FM tuner for $2 at a church fair. I hooked up an RCA indoor TV antenna, using the 300 ohm connector cables to the VHF/FM part. Pulled out the rabbit ears and turned it on. I get some poor AM, but that's par for the course here in our region. I really wanted FM, but I get nadda! Is the FM part of this old tuner broke, or am I doing something wrong? By nadda, I mean there is not even any static. I have to turn my volume in the Integrated Cary tube amp to 3/4 to hear a little hiss. The AM is clearly audible at 1/4 volume. Any advice would be appreciated. Thanks in advance....Bob