I wouldn't try to fix it myself. The circuit board could be damaged if you aren't real careful and know what you're doing -- and the circuit board is not replaceable if damaged. Just take a look at what the circuit board looks like at www.zuiko.com
to get an idea of what you would be dealing with. I would have a professional -- like Camtech -- handle this for you. Since you only paid $23 bucks for the camera, for the cost of a CLA ($140 or so), you could have a good as new OM-4 for about $160+.