downrigger question

Guys,

I am looking to buy a set of Invader Electric Downriggers used, off a guy for $150. In testing them neither of the reset buttons work--which doesn't really bother me too much. One of the two riggers pulls up and sets down fine, while the second rigger pulls ok, but will not set down the weight.

I know the thing is getting power--so the cord must be ok, so I pulled off the switch plate and checked the wiring connections and everything seemed ok. There was a loose screw at inside, that I tightened down, but the unit still will not drop the weight.

I know pricing these things new--they run about $450 a piece.

A couple questions:

1. Any ideas on what the issue might be? Wiring? Engine burnout? Etc.
2. I was thinking that I could always loosen the line wheel to lower by hand--and keep track of the depth that way. If, worst case scenario this thing is not fixable--is $150 for the pair fair price?

Thanks so much and I look forward to hearing your opinons!

Matt