A recently acquired, rather battered, OM4Ti works fine on the mechanical speeds (mirror was locked up when I got it but turning to 1/60 solved that). However, attempting to use higher speeds the mirror locks up (good batteries). Battery check does make its regular long beep sound but the lightmeter and the other electronic functions, lcd are not working. Sometimes, it comes back and fine. And sometimes it is not. I can see the lightmeter when I push a little to the shutter button and in a very small time interval, shutter speed numbers come and immediately go. When batteries are being inserted and the cap 'wiggled about' there's occasionally a short beep and sometimes even a brief flash of the red light on the front, which seems to suggest a bad contact somewhere. Battery compartment is cleaned, there is no threads. But on the bottom of the battery compartment, there is a black hard plastic plate and half of it went up. I mean, It is like a sticker kind of thing that is up. Is there a contact, wire or something under the bottom plate which could be loose, corroded or something? Can it be fixed by not opening inside? Probably not but when they open it, it costs a lot of money Any suggestions?