US Patent 7241166 Electric equipment

In order to prevent any erroneous insertion of a thin circuit board 3 into a gap 5 formed between a main circuit board 1 and a connector 2 when the thin circuit board 3 is inserted into an inserting port 2e formed at the connector 2 fixed at a mounting surface of the main circuit board 1 by electric connection, a guide 6 is formed by applying solder onto the mounting surface of the main circuit board 1 and in the vicinity of the inserting port 2e. The guide 6 can prevent any insertion of the thin circuit board 3 into the gap 5.