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Macbook 820-01958 20V 0.5A Hot CPU + Fan Spin

C

CGid

New member
Have a Macbook A2179 that came in for not powering on properly.

Customer stated it just stopped working and doing this.

System doesn't appear to have any signs of liquid damage that can be noticed.

With the battery disconnected, once plugged into power it boosts to 20V and draws around 0.4-0.5A. After a few seconds fan begins to spin and keeps ramping up. The CPU is getting incredibly hot.

PPBUS_G3H = 12.64V
PP3V3_G3H = 3.31V
PP5V_G3S = 5.10V
PVCCSSD0_PHASE = 2.5V
PP1V1_S3 = 1.1V

CPUCORE_SW1 = 1.797V
PPVCC_CPU_PH1 = 1.797V

CPUCORE_SW3 = 1.8V
PPVCC_CPU_PH1 = 1.8V

Is it likely that the CPU is dead?
 
2informaticos

2informaticos

Administrator
Staff member
Possibly bad CPU; if gets superhot, even with fan spining at max.

Caps Lock LED doesn't react?
Did you try DFU?
 
2informaticos

2informaticos

Administrator
Staff member
Really strane, as you get almos all voltages on the baord.
T2 should enter DFU.
Did you solder the switch correctly?
 
C

CGid

New member
I double checked my soldering. I don't even get a response from the power button when holding it. The machine just stays at around 0.5A and doesn't drop. CPU just continues to get hot and fan tries to keep up but doesn't. After 20 seconds the CPU is very hot to the touch.
 
C

CGid

New member
After forcing it to power off with the switch. It is still refusing to enter DFU mode. It just restarts at 0a and replicates what it's been doing of getting up to around 0.5a current draw and staying there. Regardless if I hold the DFU Force or not. I double checked soldering connections and all and they're okay. Just not accepting the force DFU, meter jumps to 0.02a when I press the force DFU switch but doesn't do anything after that.
 
Last edited:
C

CGid

New member
Yes I played around with different things for 30 minutes without getting anywhere. I did take note it can be difficult but no matter what the machine was either off, or the CPU was heating up. I wasn't getting anywhere with it. Even attempted redoing the switch wires.
 
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