Just contact XTAR : Contact Us|ShenZhen XTAR Electronics Co., Ltd
They have a ‘leave a message’ popup menu on the page.
Just say that your XTAR charger is out of warranty and that you would like to fix it yourself because you really like it.
They need the charger model and that ‘U9’ location.

They were very friendly when I asked them for a part number because I blew my XTAR VC4S due to a bad battery.
I asked what the part labelled ‘’D14KF’ was and within a day I got a reply that it’s a ‘DTS2314’.
There was some Chinese in the reply but Google can translate that for you.
It was a really nice surprise to get such great service.