I am trying to repair an old MacBook Pro which I acquired that does not boot. I know that most people on this forum either don't use Apple laptops or likely haven't tried repairing one before, but I figured I'd try asking here since most other Apple repair communities online require a paid subscription to get help or post on their forum boards... Even just trying to find a schematic and boardview (component locations) files for Apple products is a real pain.
Specifications:
MacBook Pro 15" late 2008
Model A1286
Logic board part number 820-2532-A
https://support.apple.com/kb/SP499?viewlocale=en_US&locale=en_USSymptoms: no chime, no video, white front power LED lit, green magsafe LED lit, DVD drive spins up, battery power indicator working.
I did a visual inspection of the logic board but I could not find any evidence of liquid damage or any obvious corrosion or damage. To be honest the logic board looks quite pristine for its age.
To power on the board without the battery installed, I do the following (not sure what this procedure is called):
- Disconnect magsafe power cable (no battery either)
- Hold down the power button
- Attach magsafe power cable, continuing the hold down power button
- Continue holding power button for another 5-8 seconds or so
- Release power button then immediately after press the power button once
- Both fans spin up to full speed
I measured the following voltage rails and important nets. Battery and HDD were removed before any measurements were made.
Magsafe power connected, not powered on:
PPBUS_G3H at 12.25V
PPBUS_CPU_IMVP_ISNS at 12.25V
PPDCIN_G3H at 17.12V
PP3V42_G3H at 3.43V
PP3V3_S5 at 3.324V
PP1V2R1V05_S5 at 1.104V
When powered on (S0 state):
PPDCIN_G3H at 16.76V
PPVCORE_S0_CPU at 0.988V
PPVCORE_GPU_REG at 1.005V
ALL_SYS_PWRGD at 3.30V
S0_PWR_PGOOD at 3.283V
CPU_PWRGD at 1.059V
PP1V2R1V05_ENET at 1.098V
SMC_RESET_L at 3.429V
PP5V_S3 at 5.020V
PP5V_S0 at 5.120V
PP3V3_S3 at 3.287V
PP3V3_S0 at 3.278V
PP2V5_S0 at 2.514V
PP1V2_S0 at 1.209V
PP1V8_S0 at 1.815V
PP5V_S0_CPUVTTS0 at 5.11V
PPCPUVTT_S0 at 1.059V
PM_SLP_S4_L at 3.287V
From what I can tell every single one of the voltage rails and other signal nets that I measured are all good. I don't know much more about the Apple laptop system architecture to debug much further (never even used one before). I believe that the SMC and CPU are getting power based on what the voltage rails show, but with no chime after power on means something must still be wrong. I think that no video is a consequence there being something wrong with some other part of the system, mainly because I still don't hear a chime. Connecting an external monitor to the micro DisplayPort also doesn't show any video output either.
Is anyone familiar with MacBook Pro repairs and could tell me what the next things to check for are? I don't think that power delivery is the problem. Also if you know of any other online communities for MacBook repairs that
doesn't require a paid subscription please let me know!