If your MacBook is fully functional from the battery but not from the magsafe then the overvoltage protection circuit has got damaged. There will be no green led or battery charge orange led from the magsafe. The post from nemo points to one possible problem but in my experience this is very rare. When the charge IC ISL6295 goes faulty, it tends to go in a dramatic way which prevents the whole MacBook powering on, even from battery. I have not had one yet that has gone faulty and only pin#14 has been the problem, hence why in my opinion I believe ISL6295 is not the problem, but please do not discount this yet. The overvoltage protection circuit needs two control signals, one from the SMC and the other from the charge IC ISL6295. Usually when electronic components fail, they do so in a manner which damages 99% of the component which in the majority of cases the MacBook would never power on via magsafe or battery. Due to your MacBook fully working via the battery, this would indicate that the SMC and charge IC have to be working 100% BUT it is possible that both are working 99% and the 1% fail is due to both components loosing the control signal to the overvoltage protection circuit. On ALL the boards I have fixed that are fully functional via the battery and not the magsafe it has always been 1 or 2 components in the overvoltage protection circuit that has gone faulty.
To be able to pinpoint what actual parts possibly need replacing and a diagnostic tip on determining which part needs replacing I need to know specifically the logic board type. On the labels attached to the memory socket it will usually have an id like K6 or K24 or K90. If not then imprinted onto the logic board itself will be an 820- number. The reason is there are too many MacBook pro variants and some of the circuitry is different in certain models so we need to be sure as to which model of logic board you have so we can continue onto the next part, the diagnostic tip.
hi there laptech!
i pretty new to this forum and i'm trying to get into repairing my device on my own.
okay, here's my story. i've already read at least about 30 pages of this topic and it seems that i'm at the right place with my problem.
i've got this macbook 13" (unibody late 2008) and as you mentioned above, it will power on from battery but not from the magsafe-port. so far i've checked these things:
1. macbook not charging and not running from magsafe adapter.
2. no light at all on the magsafe connector
3. macbook running fine from charged battery (just have to charge it with another mb)
4. smc reset and smc bypass won't work at all (no turning on)
5. apple power supply seems ok (outputs 6.8 v in "no load"-mode)
6. dc-board seems to be ok (6.8 v going in from the magsafe and coming out of the cable to logic board)
i'm desperately looking for help as i have no clue where to start looking for the error. another question i'm asking myself is: i've ownloaded all the schematic files for my macbook, but i have no idea, how i'm supposed to identify the different fuses etc. on the logic board.
is there some kind of software i can use, or other documents i need, where i can see how the components on the board are named? for example: how can i tell where to look for the "F6905" on the logic board?
i really appreciate your work here. it's great to learn something from other people.
i really hope you can help me!
oh and by the way:. my board has the number "W89090BP46KMA M97A 2.0G BETTER" sticked to the ram-banks. i hope this is the number you need to determine the board...
