Minolta XK AE finder issue

I recently bought a Minolta XK with AE finder. The finder was described as working except the scale was not visible in the viewfinder.

Since I already had a AE finder I swapped them out only to find mine was not working even though it was when last used a couple of years ago. The needle jumps to the top above 2000th when activated and stays there untill power is turned off. Since I know this meter was accurate when last used does anybody have an idea what may be the cause of it no longer working?

I did fix the blank scale issue on the one that came with the camera by removing the top and fishing out the detached mirror and reglueing it and the meter is working as described so I have a working meter but would like to get the other working again..