pool pilot nano power board bad

Hi

i am new here and will like some help i have a 17000 gl in ground salt water pool running a pool pilot nano 2.5 years old. for the last week is been given an alarm of low cell voltage, i have clean the cell ck fuse inside unit and finally call aqua cal and ran test. when unit gets reset and you do the reverse polarity and run the test the cell voltage goes up into the 18v and 5 amp range after a few minutes the voltage drops to 2 and amps stay in the 5 amp.
tech in aqua cal is telling me that is the power board. PN STK00061A can this board be repair and are there any schematics available.
can the problem be the cell?

thanks for the help

ER