Great, x88, thanks for sharing the experience. One update ...

With 追風大老虎's jumper method, I was able to add about 1/3 can of refrigerant in! Still waiting for MGS to come and to get a can of refrigerant with UV so that it can help to locate the leak. x88, the AC is not running for 2 summers! so could be a slow leak and I still couldn't tell if the pressure was really zero - well now it's definitely not zero - just charged.A queston - when charging, is liquid or vapor of refrigerant going in? Thank you!