Step 2: Opening the adapter
I supposed the problem should be in the cable. Time to open the black box!
Memo: Before going any further, unplug everything!
The box is made of two plastic shells fused together, there are no screws or clips, the only way to open it is cutting the junction line. Using dremel with cutting tip it take just 5 minutes. Luckly the inner circuit is protected by a metallic shell, so don't be too worried to cut something inside, just take your time and be very careful near the input and output cable.
When you can see metal on all the sides, gently open the plastic shell. there is some glue to keep all together, but it will surrender soon.