Macbook Pro similar issues
Randomly on restart or switch on I get a black screen, sleep light on no chime sound, this at one point turned into a permanent state of affairs, I stripped the machine down put fresh thermal paste on the CPU and now the machine is booting 50% - 75% of the time though doesn't like restarts. I'm writing this message on the machine in question, Im determined to get to the bottom of this issue. so I shall try as many of the suggestions here as I can so as to avoid scrapping or landfilling this otherwise fine laptop, will report back (macbook pro intel core 2 duo 2.33ghz, running lion like a champ when working).
0 : Run AHT and see if errors are the same for memory issue ?
ACTION : test faulty ram theory by removing a sim though unlikely as the ram was never an issue before this point, unlikely but possible for sim or slot to have become damaged in some way ?
1 : going to investigate whether an EFI firmware update has caused this.
ACTION : EFI downgrade or update EFI if possible
2 : Whether a pram battery failure has caused it, sometimes a pram battery reset causes it to come alive ?
ACTION : replace PRAM battery cheap and relatively easy.
3 : replace Power management charging board maybe its a failure of the Power board ? As I have used a third party charger on this laptop prior to its failure in this matter ?
ACTION : replace PMU / charging board relatively cheap
4 : stripdown to logic board removal and rebuild, tightening heatsink to logic board more than normal in attempt to effect repair if its a graphics or cpu surface mount chip issue, As logic board repair or replacement is to expensive.
Action : described above
If the above steps do not work then its probably a strip down for working parts as a last resort to prevent the machine being fully landfilled.
As per usual in laptop modern manufacture methods, the tightness of enclosures lack of ventilation in mac products causes heat based component damage, surface mount technology and the reformulation of solder to lead free(military spec still has lead in there solder), and the underspecification of a few components (for cost saving) compared to their operating environment is often the cause of the short longevity of electronics today.
we need to find a way of contact fusing/welding a components metal contacts to boards without the use of solder to create longer lasting contact between board and component this would increase the lifespan of products. that and making sure that if anything all components used are over specified compared to their operating environment. after all people pay a premium for apple product, which is why apple is sitting on a $200 biliion cash pile ?