So I bought a new iBook last year in November. After half a year with no problems at all, running off battery made the screen go to zero brightness or just shutting down. Usually when the battery was at 50% or 12% charged. I sent it in for repairs the 16th of June this year. It is now today, I have called the repair center and they said they had replaced the logic board but it still didn't solve the problem. How long should they take repairing the darn thing before I should get excited about getting a new Macbook as replacement?