Yes, I have known a very good air-conditioner engineer who have been in the industry for over 30 years, honest and professional who can fix or clean old conditioners like Carrier, Panasonic, Daikin, General, etc and maintain / resume them into a good cooling conditions, in case if your air conditioner 's condition is too worse, he is well connected with different manufactures and can arrange brand new or 80% new but used second-hand unit in very reasonable price.
I and my friends (including friend who is a management of an international school are also using his services) have been appointed him and count on him to fix & maintain all air conditioners at home and office.
You can first whatsapp him at 63967316 in case you needed, but please bear in mind since now it is peak season, it may need to take reasonably 2-3 days to schedule the first appointment with him thus would better tell him what are the issues or request you would need and check for his availability and make the first appointment first (as I have just called him Tue and he have fully checked and fixed all 3 air-conditioners (half-old and very old air conditioners) at my mom's home yesterday :)
You may whatsapp him first at +852-63967316, his name is William. He speaks fluent Japanese, Cantonese and reasonable English. Wish this would help!