Macbook A1502 820-4924-A only smc bypass (Schematics measures and boardview included)

[luel]

I have a Macbook pro 2015 model A1502
Board 820-4924-A

Liquid damage, not much corrotion, cleaned with consciousness and isopropyl

Only boot in SMC Bypass (battery, charger, trackpad and LCD connected)

In this mode booting is slow, fan is full ON, but works fine and the mac stays on.

Dont recognize the battery, AND no boot in SMC bypass if the battery is not connected


My charger is an original apple magsafe 45w 14.85v 3.05a. (I dont have any other, but is the charger used in that macbook for about 2 years without any problem)

If I test without case, just motherboard, fan and charger: green light, then orange light.

Stays with orange light, fan OFF. No heat.

Measures:

ppbus_g3h - 11.40v
PP3V42_G3H - 3.12v
PPVRTC_G3H - 3.1v
PP5V_S5 - 4.9v
PP5V_S3 - 0v
PP5V_S0 - 0v
SMC_LID - 1.98v
PP3V3_S5 - 3.1v

In add, yesterday found a component near the lcd connector, that cant remind what it is... Measured around 6v then 12v then 0v then 6v again and repeat.

In other hand I have a cap C1031 470uf CRITICAL, apparently in short. An smd tester shows me a short, this is the only one grand cap what I cant measure with tester without obtain a short, all other grand caps measure like the schematic and I not see any like this.

I think you can help me to solve this maze
Please, and thanks for read.

(I have tools, flux and soldering station to work in this board, and I can measure all other components and rails if needed.)

[mon2]

Re: Macbook A1502 820-4924-A only smc bypass (Schematics measures and boardview inclu

Remove the display.

Confirm the following again,

PP3V42_G3H - 3.12v ??

That is too low. It should be 3v42 or close to this value.

Power down, use meter in resistance mode.

Black probe on ground. Red probe on this output rail.

What is the resistance? No power during this test!!

[luel]

Re: Macbook A1502 820-4924-A only smc bypass (Schematics measures and boardview inclu

Sorry, all measures are wrong because im using a needle tester for voltages resistances and consumptions. Calibration error.

Here we go again:

ppbus_g3h - 12.90v
PP3V42_G3H - 3.42v
PPVRTC_G3H - 3.4v
PP5V_S5 - 5.18v
PP5V_S3 - 0v
PP5V_S0 - 0v
SMC_LID - 2.22v
PP3V3_S5 - 3.4v

Double checked, my apologies...

[Spider1211]

Re: Macbook A1502 820-4924-A only smc bypass (Schematics measures and boardview inclu

In other hand I have a cap C1031 470uf CRITICAL, apparently in short. An smd tester shows me a short, this is the only one grand cap what I cant measure with tester without obtain a short, all other grand caps measure like the schematic and I not see any like this.

C1031 is on CPU VCORE line, its normal to see low resistance. Where was liquid damage located on the board? Can you upload a picture.

[luel]

Re: Macbook A1502 820-4924-A only smc bypass (Schematics measures and boardview inclu

PP3V42_G3H

Using smd mini tester in resistance mode, pin 1 on c1950 shows 5.19 kohms
Tester inverted, pin 1 on c1950 shows 82.4 kohms

Using needle tester it shows 1

[luel]

Re: Macbook A1502 820-4924-A only smc bypass (Schematics measures and boardview inclu

C1031 is on CPU VCORE line, its normal to see low resistance. Where was liquid damage located on the board? Can you upload a picture.

Uploaded a capture of the c1031

Do you wanna that ? or a general picture of the board?
Has been wet on the upside near the battery and otherside also.

CPU and RAM were safe, I guess...
When I see that, case open, disconnect battery and cry...

[luel]

Re: Macbook A1502 820-4924-A only smc bypass (Schematics measures and boardview inclu

A picture of the SMD Tester

[Spider1211]

Re: Macbook A1502 820-4924-A only smc bypass (Schematics measures and boardview inclu

Picture of the board (Both sides), especially where there was water. Do you have a bench power supply? If yes, what is the current draw of the board?

[luel]

Re: Macbook A1502 820-4924-A only smc bypass (Schematics measures and boardview inclu

If I put the board on the case, whit battery (completely discharged) and magsafe, screen shows charging but never boots up. If I try to power on, shows charging battery.

Just boot in SMC bypass, without recognize the battery, load OS and stay ON. All works. That make me think was the problem can be fixed...

I need to replace a knob in the power supply to use in this. If I can solve without external power supply will be good

[luel]

Re: Macbook A1502 820-4924-A only smc bypass (Schematics measures and boardview inclu

What do you mean with this?

"If yes, what is the current draw of the board?"

Its to measure consumption? Inject voltage? Or just replace the magsafe?

[piernov]

Re: Macbook A1502 820-4924-A only smc bypass (Schematics measures and boardview inclu

https://www.badcaps.net/forum/showthread.php?t=88758

Always make sure the correct AC adapter was used with the machine. Genuine original AC adapter of the correct brand and correct power rating. Even if the connector is correct, it doesn't mean it will work and it can even damage the machine.

https://support.apple.com/en-us/HT201700#magsafe2

MagSafe 2

60W MagSafe power adapter with MagSafe 2 style connector

13-inch MacBook Pro models introduced in 2012 through 2015

[luel]

Re: Macbook A1502 820-4924-A only smc bypass (Schematics measures and boardview inclu

Its not the recommended charger for this laptop, I know... But is the charger I used for two years until the liquid damage.

It should reach the function as well... Or not? The charger is not the problem here, damage is for liquid!

[piernov]

Re: Macbook A1502 820-4924-A only smc bypass (Schematics measures and boardview inclu

You have an issue with the battery and the AC adapter is the wrong one. If both power sources for the machine are a potential problem there's surely no point in messing with the board.

[luel]

Re: Macbook A1502 820-4924-A only smc bypass (Schematics measures and boardview inclu

Today I tried with another original magsafe 2 60w. Only boot in SMC bypass, and Starts without battery on SMC bypass. Fast orange light, then green light (for about 2 seconds), then orange light and stays here.

Measures:
--------------------------------------------------------------------------
PPBUS_G3H - 12.9v
R3080 pin 1 --> PPBUS_G3H 12.9v
R3080 pin 2 --> TBTBST_PWREN_DIV_L 8.4v
C3080 pin 1 --> PPBUS_G3H 12.9v
C3080 pin 2 --> TBTBST_PWREN_DIV_L 8.4v

I see some brown in Q3080 surface
Q3080 pin 1 --> TBTBST_PWREN_DIV_L 8.4v
Q3080 pin 2 and 3 --> PPVIN_SW_TBTBST 0.5v (TP1-R3088-R3091 shows a peak on 0.1v and goes down to 0.05v then stays
here)
Q3080 pin 4 --> PPBUS_G3H 12.9v

L3095 pin 1 --> PPVIN_SW_TBTBST 0.1v to 0.5v stable
L3095 pin 2 --> TBTBST_BOOST 0.1v to 0.5v stable
C3091 pin 1 --> PPVIN_SW_TBTBST 0.1v to 0.5v stable
C3091 pin 2 --> GND
C3090 pin 1 --> PPVIN_SW_TBTBST 0.1v to 0.5v stable
C3090 pin 2 --> GND

PP3V42_G3H - 3.42v
PPVRTC_G3H - 3.4v
PP5V_S5 - 5.18v
PP5V_S3 - 0v
PP5V_S0 - 0v
SMC_LID - 2.22v
PP3V3_S5 - 3.38v

[piernov]

Re: Macbook A1502 820-4924-A only smc bypass (Schematics measures and boardview inclu

Pm_batlow_l?

[luel]

Re: Macbook A1502 820-4924-A only smc bypass (Schematics measures and boardview inclu

PM_BATLOW_L

TP1 --> peak on 0.0875 then goes down to 0.035v (stable at 0.035v)

R1410 pin 2 --> PM_BATLOW_L --> peak on 0.0875v then goes down to 0.035v (stable at 0.035v)
R1410 pin 1 --> PP3V3_S5 --> 3.38v

Q3000 pin 1 --> PP3V3_S4_TBT --> 0v
Q3000 pin 2 --> TBT_BATLOW_L --> 0v
Q3000 pin 3 --> PM_BATLOW_L --> peak on 0.0875v then goes down to 0.035v (stable at 0.035v)

[Stephen]

Re: Macbook A1502 820-4924-A only smc bypass (Schematics measures and boardview inclu

Piernov has a point. You need a 60W OEM charger. I highly recommend you do this now. Stop using the 45W (even after 2 years) doesn't matter what you believe and or if it works, you need to use the proper wattage for these MacBooks to function properly. I HIGHLY recommend you get a 60W before going further trying to diagnose your laptop. AGAIN I REPEAT, do not get a 60W Amazon charger, You have to use an APPLE 60W MagSafe 2 OEM Genuine Charger.

[luel]

Re: Macbook A1502 820-4924-A only smc bypass (Schematics measures and boardview inclu

First, thanks for your time to read and help me.

YES, the charger used for the last measures is an APPLE 60Watts MagSafe 2 OEM and genuine.

If I want to fix this board, I need to respect the steps of your guide. So, I will not lie.

Reading a lot of threads and posts about Macbooks boards, I understand that is absolutely necessary. For this reason, I had to search a 60w Apple MagSafe and come here again.


Measures with Apple MagSafe 2 60watts:
--------------------------------------------------------------------------------

----------------------
PM_BATLOW_L
----------------------


TP1 --> peak on 0.0875 then goes down to 0.035v (stable at 0.035v)

R1410 pin 2 --> PM_BATLOW_L --> peak on 0.0875v then goes down to 0.035v (stable at 0.035v)
R1410 pin 1 --> PP3V3_S5 --> 3.38v

Q3000 pin 1 --> PP3V3_S4_TBT --> 0v
Q3000 pin 2 --> TBT_BATLOW_L --> 0v
Q3000 pin 3 --> PM_BATLOW_L --> peak on 0.0875v then goes down to 0.035v (stable at 0.035v)

[piernov]

Re: Macbook A1502 820-4924-A only smc bypass (Schematics measures and boardview inclu

PM_BATLOW_L should go high if using a genuine Apple Magsafe2 60W. It needs to be a genuine Apple one, not a random eBay one, even with Apple logo, or a "refurbished" genuine one with a random cable, it needs to be Magsafe2 (not 1 even with 1 to 2 adapter), and it needs to be 60W or 85W. This board is very picky about it.