5 - OPEN

Rear of OM-4 front casting. Arrow points to pulley and string system that controls the coupling ring inside the mirror box. If this string breaks coupling ring may not return to start position. Switch to the right of the arrow controls self timer and / or turns battery check / self timer beep on and off. In oldest style OM-4, this switch (which is spring loaded) would unwind if the front red cover came unscrewed. This proved VERY difficult if not impossible to get back into position from that front hole. Camera would have to be disassembled to this point to reset it.