question about an Olympus 35SP I picked up

This question concerns the 'spot' button on the back. Assuming there is a difference in tone on the scene in the central area of the rangefinder, is the needle on the EV scale supposed to move when the button is pressed (ie, going from 'average' to 'spot')?

On mine it does NOT, even when on autoexposure. Metering is fine, albeit 'average' only. Am I doing something wrong? And if it is supposed to move (most rational) is the top easy to remove by unscrewing the film advance lever and film rewind knob so that I can check the internal connection? There are no other apparent screws on the top (I am used to removing tops from cameras). Thank you. - David Lyga

Hi

You are holding it down until after you take the shot?

Noel
http://www.cameraquest.com/olysp.htm

I just bought it at a flea market. I have not run film though it yet. But it seems that the indicator needle would move (upon pressing the 'spot' button) BEFORE the shutter was pressed, in order to prepare for the new EV in advance. Is the 'exposure change' made WITHOUT the needle indicating anything has been changed?

I am thinking here of similar situaions like the Canon AE-1 where pressing the 'backlight' button on the side of the lens mount area indicates 1.5 more stops exposure will be given. - David Lyga

Could be a dirty/tarnished switch. It's just a push button.
The top should be pretty simple to remove, but once you get the lever & rewind knob off there may be a concealed screw or spanner nut there.

There should be a difference in readings if the center of your subject is brighter or darker than areas along the edge of the frame.

The meter cell is made of two parts, the outer part reads at most times, pressing the switch energizes the center part of the cell. The switch is a simple leaf type, and may not be getting contact, or the wire leading to the meter may be grounded out. This sometimes happens when the top cover is removed and replaced.