Ok. With batteries in the replacement holder and main power turned off, set your DMM to Volts DC.
(If it's not auto ranging, then you will also need to select the appropriate range to measure around 5 volts DC).
Put the black lead on pin 8 (Ground) and the red lead on pin 22.
Pin 8 is the eighth one from the left on the bottom row of pins, and pin 22 is top leftmost pin, as the chip sits on the board.
Let us know what reading you get.