I also recently got an EXC+++ / near mint OM-1 in black that has a broken plastic battery connection screw so the meter doesn't work.
I think it happened early in the camera's life so it spent many years unused on a shelf somewhere. The advance lever stiffened up to the point where you have to force it closed.
I removed the top to take out the melted foam and lubricated the film advance shaft and it 'sprang' back to life.
The camera works great now. (well, except the meter still doesn't work due to the plastic screw and of course it has a touch of the prism grunge...)