Our house air-con outdoor unit got problem and since then, we are living without air-con for past few weeks.
Luckily now is quite cooling weather and we can live without air-con.
Today, finally we got air-con service men for find out the problem.
They said that MiXXXbishi is quite often face problem in outdoor units' circuit board and once spoilt, need replace with new one while DaiXXn is more tough and can be repaird instead of replacing new one.
We also asked them to clean master bedroom's indoor unit, simply because we never cleaned it before (for about 2 years).
We decided to ask them to master room indoor unit for every half yearly and common room & living room for once a year basis.
We only use air-con for a few hourse before sleep every day for master room and the rest only use a couple of time in a year.
New circuit board was $250 and 1 indoor unit cleaning charge was $30.
They are doing this business for more than a decade and their cleaning procedure was quick and quite skilled.
Thank you air-con Mr.N!