Bugis Street there. Repaired my Z5 there. Reasonable priced.
Dare to recommend cos has a scenario whereby I was paranoid with some issues the guy told me he was ok to help me open up and check and can do it for free to assure my paranoia, just that he was sure it wasn't a present issue and advised me against disassemble it too much.
The repair shop beside Wo Ai Taimei