150 Watt CC

[Craigrrr]

While I was looking in the garage , I found my old 150 Watt charge controller that was installed in our 1994 Holiday Rambler Class A mounted in the basement storage bin, only has 3 led's and a trim pot to adjust input voltage from panels . Is there anyway to tell what the max voltage would be of this unit or is it just hook up and chk for smoke