Macbook pro 13'' A1502 820-3536-A

[sauce]

Hi,

I am trying to repair this motherboard with no light on charger.

On the board R7020 was not in good condition (like it was slightly burnt)

And there was a short to ground on PP3V42_G3H.

By looking carefully C7099 was strange so I desoldered it.

The short has gone but on multimeter capacitor has a good value and is not shorted.
Quite strange, isn't it ?

I desoldered R7020 and its value is 37 ohm instead of 47 ohm so I need to replace it I think.

My question is on this R7020. On the schematic is a 47R 1/3w 0805 metal film 1% that's it ?

But why is it green ? Normally cms resistor are black so is it a special resistor ? Like a fuse resistor ?

Do you have a link to buy such resistor ?

Best regards.

Sorry for my bad english I am french.

[mon2]

Re: Macbook pro 13'' A1502 820-3536-A

R7020 is not a critical value to the power supply that creates this 3v42 rail.

So 37 ohms is fine for now.

Continue to test downstream of this area.

Meter in DIODE mode. Remove all power = no adapter & no battery.

Red meter probe on ANODE (pin # 1 of D7005). Black on CATHODE, pin # 3 of D7005. What is the reading on the meter?

Then reverse the meter leads. What is the reading on the meter?

Perform the exact same testing using pin # 2 of D7005 & pin #3 of D7005.

Often D7005 will get damaged but confirm this common cathode DUAL diode.

Your magsafe (original) power supply LED in the head connector will not light up unless this 3v42 rail is operational.

[sauce]

Re: Macbook pro 13'' A1502 820-3536-A

I already tested D7005 in diode mode everything is OK.

I tried to plug charger without C7099 and there was the green LED and then orange LED.

But if I unplug and plug the charger again LED not switch on each time maybe because C7099 is missing for now (critical on schematic)

[mon2]

Re: Macbook pro 13'' A1502 820-3536-A

With your meter in resistance mode, check the resistance across c7099 while it is removed and on your table.

What is the reading?

Is it shorted or with a low resistance?

[sauce]

Re: Macbook pro 13'' A1502 820-3536-A

Hi,

No the resistance is very high just test and more than 1Mohm.

Really strange because once I removed it no more short.

[mon2]

Re: Macbook pro 13'' A1502 820-3536-A

Maybe the cap was not soldered onto the pcb correctly?

Check the rail resistance to ground without power of course.

Then solder back this cap and measure again. If resistance is not too low, the cap is fine to use again.

[sauce]

Re: Macbook pro 13'' A1502 820-3536-A

So before resoldering : 25k ohm to ground
After soldering : 13k ohm to ground

Really strange because I have another card but 3476 and resistance to ground at the same point is 0.5M ohm !

But the 3v42 is working and LED pass from green to orange.

I will try to put it in the laptop and see what happens.

[sauce]

Re: Macbook pro 13'' A1502 820-3536-A

Ok so I placed the motherboard, plugged all cables and the mac runs but won't boot on SSD (question mark).

I ran apple diagnostics all is ok for it.
But if I boot to reinstall and go to disk utilities he says file system error and won't repair.

Any ideas ?

[ACS-Repair]

Re: Macbook pro 13'' A1502 820-3536-A

I've think I've seen something like this before...
You could try booting from recovery or external install disk, then opening Disk Utility.Make sure you're looking at all devices, not just volumes. Then try deleting the volumes and partitions on the drive rather than trying to repair it. After that, try to do an erase at the highest device level to format the drive.