Philips MCD 190 DVD Micro Theatre System

This cute microsystem was popular in 2005 in India. I purchased it in 2005 too. it is one of my favorite ones. I handled it very carefully. It has a DVD, Cassette Player, AM/FM, and AUX input. It produces a 5-watt RMS per channel output through two bass-reflex wooden bookshelf speakers. The sound is very soothing in the living or bedroom. At present Cassette and FM section needs service. Probably a pinch roller needs to be changed in the cassette deck. Don&know why the Sound in FM, since the last year, has gone down to a lower level at the exact station frequency, say when I tune 98.3, 101.1, 101.8, or any other station, the sound goes down. Any Idea? I&very little knowledge of electronics but am scared to go for servicing because of the fear of losing its originality. Please share your comments...thanks for watching.