A1398 820-3787-A fan spin, no chime

kantuni

New member
Hey folks,

I'm new to electronics, so please forgive any noob questions/mistakes.

I'm trying to repair a 15" MBP Mid 2014. It froze a few times. After the last freeze, I wasn't able to proceed further than the boot launcher. It's running Ventura (OCLP). When I connect the charger (with battery disconnected), I get the green light followed by the orange light, the fan spins, but I there is no chime.

After a cleanup and a thermal paste replacement, I got chime once and everything worked as expected. After a shutdown, the computer was back to the "no chime" state.

Here are the measurements I did so far:
PPBUS_G3H - 12.59V
PP5V_S0 - 5.03V
PP3V3_S0 - 3.32V
PPVCC_S0_CPU - 1.79V
PPVCORE_GPU - 0.89V

P.S. Should I be measuring these with the LCD cable connected?
 

2informaticos

Administrator
Staff member
First of all, welcome to the forum!

These voltages look good.
But MLB requires more things to happen, before boots.
Be sure to use 85W Magsafe 2 charger; this board doesn't turn on wiht 45/60W charger, if battery is empty/disconnected.
Doesn't fix on chime only; check Caps Lock LED reaction too.

Check if PLT_RESET_L goes high.
 
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