Thats why i damn scared of aircon repair people...
First of all, the aircon troubleshooting by aircon repairman is not done properly. Hence the spark was due to electrical problems but the aircon fellow is ignore and ask owner to change whole aircon unit??? for 800sgd for a sub unit is too expensive! a normal sub unit is around 150-200sgd mah... even add installation also 50sgd onmly mah... where got 400sgd??? some more charged 800sgd!
Either the repairman doesnt know what he is doing and just hamtam try his luck and replace one by one and soon will surely fix the problem loh.
OR that repairman is simply dishonest. HE hides the fact that in the first place, the electrical parts are faulty and he dun wan to troubleshoot and make owner replace the unit... so the problem is still there and will be faulty again and call him up again to fix aircon again. That uncle repairman also said that without opening up the false ceiling he can nvr confirm the problem, so he actually doesnt know the wiring is faulty. He just suspect its wiring faulty... high chance opening the false ceiling also wont fix the problem if he cannot or wont troubleshoot the problem.
In the end, this kind of aircon serviceman will ask u replace whole aircon unit.
Wait till u encounter such case, see how tulan or totally kena con by the aircon people and still praise them for their professionalism.