the "heatsink" mood is useful to prevent cpu soldering failure, not to fix it once it occurs. I usually make such a mood after i reheat the cpu and test the phone.
At first i was thinking it's a simple high temperature problem (ex. cpu must not exceed 50 degrees celsius) so i made the heatsink mood. It ameliorated the problem but did not effectively solve it. Later on, i've reheated the phone, only this had effectively fixed the problem. I left the heatsink on the cpu because i was concerned that without any means to dissipate heat the cpu soldering can fail again after some time. The role of the heatsink is NOT TO LOWER THE CPU TEMPERATURE, BUT TO SPREAD IT OVER A GREATER AREA. The cpu fails because it is very hot, the surrounding pcb near it is rather cool, the soldering thus expands at a greater rate then that of the surrounding materials. The 50 or so, degrees celsius that this chip can output ar not the real problem (it can work just fine even at 70-80 degrees - according to datasheets). The soldering and the pcb design are more of a trouble here.
Samsung Galaxy Note
- Mr. Big...
running windows in the morning and android at evening (gave it to GF)
some cpu problems, needs a heatsink redesign
PDA/Laptop service for some years. Seen a lot of broken things in my life.