I recommend to call Benq for a offical help.
真的很建議打電話去benq問

That wo'nt take too much time , and fixing the scanner may not cost you too much money.
這並不會花費太多時間
送修scanner也不一定會花太多錢

It's quite hard to tell you some other way to solve your problem on the internet, and "Good luck" is the only thing I can tell you.
而我們在網路上很難以其他方式去替你解決這問題
我也只能祝你幸運