MacBook Pro A1708 820-00840 - 20v, 0.5a, Fan Spinning

gap-ruse-pried

New member
I have a MacBook Pro A1708 non touchbar that wont boot. Getting 20v, but only 0.5a when ssd is disconnected, around .65a when ssd is connected.

Upon plugging in usb c power, the fan spins for 30 seconds then stop. It’ll go again after a little while, but stop again. Like it’s trying to start but can’t.

Tried caps lock and got no light. I do have a usb c to regular usb adapter, so I plugged in a couple flash drives. One of them was blinking rapidly and consistently, the other didn’t blink at all. When I plugged them into my regular pc, they both light up and flashed normally.

Also tried a usb c to hdmi adapter in case it was just a display issue, but I didn’t get an image on the monitor.

I’ve tested some components as noted below:

PPBUS_G3H (F7000) ~13.08 V
PP3V3_G3H (C7080) ~3.42 V
PP5V_S5 ~5.12 V
PP3V3_SSD ~3.32 V
PP1V8_S0 ~1.8 V
PPVCCCPU_S0G ~0.95 V
PPVCCSA_S0G ~1.04 V
L7410, L7420, L730 0 V
SMC_RESET_L ~3.42 V
SMC_BC_ACOK ~3.42 V
PM_RSMRST_L ~3.3 V
PMIC_RSMRST_L ~3.3 V
PM_SLP_S4_L ~3.42 V
PLT_RST_L ~3.32 V

Not sure where to go next? I have experience with microsoldering but mostly on consoles. This is my first time doing any sort of Mac repair, so any guidance is appreciated!
 

2informaticos

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

Monitor CPU core voltage.
It should drop to 0.65V aprox, after 10-15s; when board really boots.
BTW, it is available at L7210/20 for test.

Do you have known good battery, holding some charge?
 
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