Nikon FM2 light meter works, but incorrectly

[SoulfulRecover]

Yesterday I noticed that the light meter in my Nikon FM2 is not giving an accurate reading so I decided to try swapping out the batteries. It did not make a difference. To give an example, it was telling me that the correct exposure for f1.8 with 400 ISO film in mid day was 1/2 second to a 1/4th.

Anyone have any ideas on what to check or how to go about fixing this? I made sure the ADR-Window was clean which had been suggested on another forum but this did nothing as well.

 

[cgw]

Is the Ai tab moving freely as you turn the lens's aperture ring?

 

[SoulfulRecover]

Is the Ai tab moving freely as you turn the lens's aperture ring?

yes sir it is.

 

[cgw]

Does the ISO dial work properly?

 

[SoulfulRecover]

I think so. I can pull it up and it'll click over 2 stops but then catch and turn the shutter speed. So ill have to let it down then pull up again and it'll click 2 or 3 stops then catch again. Maybe something in there isn't allowing the ISO to be set correctly?