FM3a photometer problem

[Henry Alive]

Hello everybody:
I have just bought a second hand Nikon FM3a, and it seems to be in very good conditions. However, there is a problem with the photometer. I work with TX400, EI200. In order to get the correct exposure, I have to put ISO 500 in the camera instead of ISO 200. This little trick allows the camera to work perfectly; however, I am going to repair it.
Have some of you had this problem? Have you repaired it?
Thanks for the comments,
Henry.

 

[Ian Grant]

Are the batteries the correct voltage. Take away the sweet Fa and leave the M3 and I'd tell you, as my Leica uses a Selenium meter

Seriously a major problem is the difference in Voltages between current batteries and banned Mercury cells, you need to check.

Ian

 

[johnnywalker]

According to my FM3A manual, 3 types of batteries can be used: One 3 volt lithium battery (CR -1/3N type); Two 1.55 volt silver oxide batteries (SR44 type); or two 1.5 volt alkaline batteries (LR44 type).
Don't mix the types where two batteries are required.

 

[Nicholas Lindan]

second hand Nikon FM3a ... I have to put ISO 500 in the camera instead of ISO 200

You may have the wrong focusing screen installed.

Nikon upgraded the focusing screens in the FM/FE series and the newer ones are one stop brighter than the old ones. If you have an old screen then this is about the error you should be seeing. The manual should have information on the proper screens - going from memory the have a '2' in the identifier, such as 'E2'.

If this is the problem then adjusting the ASA dial is the solution, that or buying a new screen with a brighter view. No repair is needed.

 

[Henry Alive]

Thank you for the comments. I have checked the focusing screen, and it is the E3 that corresponds with this camera.
I have also put new batteries. However, there is still the same problem. I think I will go to Nikon service to repair it.
However, I would like to ask you a new question: If you compare the FM3a (or another manual camera) photometer value with an electronic camera (like F100, F80, etc) photometer, both with central valuation and the same light situation, Do you get always the same exposure? It is supposed to be the same; however, I find strange measures with my F100 and FM3a.
Henry.

 

[Nicholas Lindan]

If you compare the FM3a photometer value with an electronic camera (like F100, F80, etc) photometer

You should get the same reading from a uniformly lit blank wall.

The metering patterns in most electronic cameras won't match the bottom-center weighted scheme in an FM series camera. If there is detail in the scene the metering systems may come to different conclusions about the right exposure - no worse than getting any two photographers to agree on the right exposure.