macbook pro 2014 (820-3787-A) EFI

john

New member
I have this macbook pro 2014 (820-3787-A) it's my personal computer was working fine until one day I found it with fan spinning and black screen. I turn the macbook off and on again and there was no imagine on the screen and was looping on chime sound. Because I had issues before with this mac I decided to pull the bios chip from one board to the other. now the computer is turning on but no imagine. Theres any tutorial how I can flash a new cip?
 

dukefawks

Administrator
I can tell you 100% there is nothing wrong with the ROM. Put back the original. Looping chime is usually a RAM or GPU issue.
 

john

New member
with the other chip from the donor board is not doing any looping chime. I will put it back. where should I start troubleshooting?
 

dukefawks

Administrator
I cannot tell you where the corrosion is, you saw the original damage. Does it chime with the original BIOS back on it? Do NOT reflow if fully, just some flux and 150C heat should clear the crap under whatever chip the corrosion is under.
 

john

New member
ok I found r6324 with a missing cap. I did replace it now the machine is turning on only if is plugged to the battery and the charger if i take the board out and plug the charger it doesn't turn on
 

john

New member
PPBUS_G3H 12.58V
PPVIN_S5_HS_COMPUTING_ISNS 12.58V
PPVIN_S5_HS_GPU_ISNS 12.58V
PPVIN_S5_HS_OTHER3V3_ISNS 12.58V
PPVIN_S5_HS_OTHER5V_ISNS 12.58V
PPDCIN_G3H 16.49V instead of 20V
PPDCIN_G3H_ISOL 17V instead of 20V
PP3V42_G3H 3.41V when I took the measurements at l7095 the fan start to spin. i disconnect the power cable put it back on and again no fan spin
PPVRTC_G3H 3.41V
PP5V_S5 5V
PP3V3_S5 3.3V
PP5V_S3 the voltage it's dropping slowly to 0 and its starts all over again
I'm really lost on this board
 
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