To check the electrical function of the OM Data Back, you need a electrical wire with clip, a 10X lupe and a small piece of semi-transparent sheet (the one use to store the negative).
First, check all the program buttons to see if they response. Connect the clip to the hinge shaft of the Data Back, with the other end of the wire touching the golden contact pin on lower left of the Data Back, the LEDs should light up (a short pulse). If you want to see the segments more clearly, cover the LEDs with a small piece of semi-transparent sheet and put a 10X lupe (similar magnification may also work) on top, you will have a very clear view of the characters.
