97 Galant FM reception problem

Hi,

97 Mitsu Galant ES, Auto. I've a factory AM/FM radio with cassette player. The cassette player and AM radio works fine, but there is no reception in FM. I received FM only once after I bought the car about a year ago. I've checked the Antenna connection both at the back of the radio and at the antenna in the trunk, it is perfect. Also if I take the antennal connection off, AM radio shuts off - so the antenna works ok. What else might go wrong ? Any sugestion what else I should check to pinpoint the problem? The LCD display is burnt out and I do not have the manual. So any help will be appreciated. Thanks in advance. Morshed