What problems?

I bought one for $70 on ebay. The 100 amper like in your picture.

It never came with instructions but, being the smarty pants i am, I could tell it was a Hacker knock-off. So since I didn't get any instructions I tried my Hacker program box.

By using the hacker Navy 70-opto selection I was able to program it perfectly I have since sold it to a friend and its still working fine.

I wouldn't push it much passed 75 amps for long, its just too small for a reall 100 amps IMO.