marantz 2225 stereo light

just bought 2225. changed fuse lamps and all okay. the problem is the stereo light does not go on in when selector is in fm,its works on phone/tape and aux. when the signal strength is strong 4/5, the tuning meter if slightly off center. when I center the needle the strength meter falls. is this an indicator. please advise . thanks
I cant get stereo light to go on in fm mode. installed new bulb which works only in tape/phono/aux. Im a novice at this. wondering if Im stuck in mono. I've sprayed the inside switches. mono light works in other modes but does not sound like it works in fm. please advise your thoughts.
If the stereo light is actually good, the most common problem is alignment. The tuning meter has a relationship to the ratio detector- if the ratio detector is out of alignment, the correct setting of the meter may not be at the peak. If the unit has this problem, it may not be able to detect the stereo subcarrier, thus the stereo lamp will not light.

So alignment is the first thing to check. For this you need actual test equipment- an FM Stereo generator for starters.