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820-00840 No Wi-Fi + No drive detected

overshoot

overshoot

Member
Hi,

I've got that MacBook and after first inspection it looks good inside.
I couldn't find any liquid damage or corrosion.

The drive has been tested in another machine and is working fine.
It is clearly a mainboard related issue. The Wi-Fi is also not detected however bluetooth works.

What are the shared components or lines between those 2 problems?
Please don't tell me the CPU?!...
 
overshoot

overshoot

Member
Hi,

I think you were looking the wrong board model. Those parts do not exist on the board.
BTW, it's a 820-00875 however I've checked on the 820-00840 (which is very similar) and those parts number you gave me do not exist either.

Thanks
 
2informaticos

2informaticos

Administrator
Staff member
You're right, I was looking different schematic, probably 00165.
This happens sometime, as I usually have 15-20 pdf schematics open.

Check R2011/12.
 
overshoot

overshoot

Member
Both are 100k resistors as expected.
When powered on, the signals are at 3.3V so no reset on both lines.

Regarding the SSD, I have 13V on PPBUS_SSD_FLV.
I also 3.3V on SSD_EN.
I have 3.3V on SSD_SR_EN_L ????
I have 3.3V on PP3V3_SSD_FLT
L8630 is testing fine (4 ohms)
I am getting 1.8V on the PP1V8_S0

Anything else I could test?
 
overshoot

overshoot

Member
My reading might be a little bit off with the probes.
I am getting 3 ohms on a known good board for that coil.
 
2informaticos

2informaticos

Administrator
Staff member
Do you get 3V on all pins of R2011/12?

Compare voltages and diode mode readings between the two boards, on the related areas.

Did someone else work on the board before?
Check for knocked off components...
 
overshoot

overshoot

Member
I believe somebody has it in hands but it looks like nothing was done.
I am just wondering if they could have flashed the Bios with no clean ME region.

Could that be possible that it would be messing up with the drive detection + Wi-Fi on this model?

I can't find any missing components.
And yes I am getting the 3V on both resistors.
 
overshoot

overshoot

Member
My bad!... The board is a 820-00875 so Bios did not work.
The board did power up but was brain dead. Fan wentfull speed and nothing else happened.

Any Bios with Clean ME for an 820-00875.

Thanks!
 
overshoot

overshoot

Member
Nevermind it's not the Bios. I've tried one and same results.
I will investigate the board more when I have some free time.
 
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