Livorsi GPH meter quit working

[Bob & Sue]

I have a Livorsi GPH meter that hasn't worked since we bought the boat not sure which sending unit is on the gas line it is black about 4" long x 1" in diameter. I have read there is a reset button on the meter but can't find it anybody know what might be wrong or where the reset is? If I can't fix easily will put a garmin gfs-10 flow sensor on it.
Thanks in advance