820-00045 liquid damage not turning on

[arnonabuurs]

Hi Guys,

I have an 820-000145 2015 Macbook 12 inch thats liquid damaged. The charge port cable had a corroded pin, swapped that out. The Mac does not start. I know I need 20V on F4700 pin 1. What I get there is a voltage between 0-5v thats seems to turn on and off rapidly, unlike in the video from Louis where it showed a stable 5V. What could be the issue? It looks like no liquid has reached the logicboard, checked carefully with a microscope. The OAN line is also pulsing, between 0-2.9v.

 

[dukefawks]

Using the correct DCIN cable, there are a few different ones. Checked rails for shorts?

 

[arnonabuurs]

Yes im using the correct one. No short on F4700 and diode measurement gives me 0.546v on pin 1. Will got through all rails now to check for a short and report back.

 

[arnonabuurs]

Short on CPU? I believe all shorted lines lead to the CPU ?

PPBUS = 0.470
PPVIN_G3H_P3V3G3H = 0.535
PPBUS_S5_HS_COMPUTING_ISNS = 0.469
PPVBUS_E85 = 0.547
PPDCIN_G3H = 0.567
PP3V3_G3H = 0.407
PP3V3R3V0_AON = 0.338
PPVRTC_G3H = 0.267
PP5V_S4 = 0.425
PP3V3_S5 = 0.380
PP3V3_SUS = 0
PP3V3_S4 = 0
PP3V3_S0 = 0
PP1V05_SUS = 0
PPVCC_S0_CPU = 0

 

[dukefawks]

Uhh if that many rails are shorted then yes this is RIP. Do check on Ohm setting if they are really shorted though.