Milwaukee 2612 rotary hammer drill trigger issues

[Hector]

Hi guys, 

 

First time posting here. Im trying to repair a Milwaukee rotary hammer drill, model no - 2612. I brought used, "site unseen" so to speak, off a buy and sell and got he seller to ship it to me. When it arrived it turned out it was in pretty used shape, worse then what I thought the photos made it look. It worked right off the bat but failed soon after, needless to say, lesson learnt well learnt.

 

The problem is showing up when Im depressing the trigger, its ramps up through the variable speeds fine but then cuts out when it hits full speed. It does this consistantly. I have tried looking through some forums and watching a few youtube videos (my usual way to figure things out) but I havent repaired many power tools before and my electrical knowledge is pretty abysmal.  I opened up the trigger and gave it a little swab with some ear buds, it cleaned up a bit but didnt fix the issue. Something maybe of note, when I had the trigger apart and the battery still connected, I depressed the trigger and I would get a small ringing noise (the same as you get in your ears sometime) this noise would continue all the way through the stroke of the trigger and wouldnt cut out at the end of the triggers stoke. I figured this to mean that the problem isnt on this side of the trigger as its not cutting out power to the tool at the end of its stoke? thought this might mean the issue is further down the line, perhaps on the removable cover plate of the trigger, where the main trigger contacts? (hope that makes sense). I will try to upload somephotos. 

 

Wondering if anyone could help give me a bit of direction on this? I run my own carpentry / contracting business and enjoy learning how things work and how to fix stuff when it  breaks so am keen to try and figure this one out.

 

Thanks in advance.

[Hector]