(Refer to this thread for a similar problem: https://forum.allaboutcircuits.com/threads/milwaukee-m18-rapid-charger-repair.168077/#post-1667661)

Hello, I am sorry to revive this topic. I have one of these chargers myself I'm trying to fix.

In my case it was somewhat obvious what failed. There is a part marked U3 on the board - It's a 1911 Top261EN integrated offline switcher... It blew some of the legs off completely.

I suspect the charger failed due to grinding dust incursion since my boss in his infinite wisdom thought right next to the grinding wheel was a good location for a battery charger..

I just wonder if it's worth it replacing that blown component and hoping it will work?

The charger is completely dead. I did clean the pcb off in my ultrasonic cleaner, and at 85c water temp, the conformal coating came right off

It blew black snot over a large area of the pcb... That part is attached to a large aluminium heatsink, it's glued to a small tab that's screwed to the heatsink. The black stuff you can see on the pcb, is grinding dust that didn't come off in the ultrasonic cleaner, I suspect some rounds with the airgun will get it off though..

 

Excuse me but can anyone look at the value of R38

Might be a bit late, but yeah, it's marked 122, so 1.2 Kohm