A1502 2013-2014 13” MacBook Pro Retina

Ribbon connector to keyboard bend/dirty/broken (bend back/clean/replace)

Example: https://www.youtube.com/watch?v=QnowcxcO2-0 (second repair, ribbon connector bend/dirty)

• PM_SLP_S4_L missing for random reason, thoroughly inspect clock chip, tiny specks of corrosion next to it can kill it. Sometimes shotgun replacement of the chip is a clean solution.
• Bad U1900 clock chip
• Bad right I/O board. Unplug it, see if it works (short on 3.3 V or 5 V rail on the I/O board can cause this problem).

Corrosion at U1950

Example: https://www.youtube.com/watch?v=X2UlXmMMn6Y (replaced U1950, capacitor and resistor)

• ADAPTER_SENSE not 3 V due to bad DC in board. 16–20 V on ADAPTER_SENSE means charger voltage is leaking into ADAPTER_SENSE, below 2 V means it is missing usually due to a bad DC in board.
• PP3V42_G3H missing
• SMC not working(if SMC is off, you will have 12.23 V on PPBUS_G3H instead of 12.56 V) because it is dead, not turning on (SMC_RESET_L low).

Example: https://www.youtube.com/watch?v=FlaUiYB9FbM (U5110 (chip responsible for SMC_RESET_L) not working)

• Corrosion of the SMC solder connections

Example: https://www.youtube.com/watch?v=YUPH7Vaama4

• Keyboard bad, shorting PP3V42_G3H to ground or power button stuck on.
• Bad U7000/U7001.

First, try a known good battery.

If it doesn't work, check PPBUS_G3H. If it is 12.23 V, the SMC is not communicating with the battery on its data line, either because the SMC is bad, or because the pull-up resistors on the data line are bad. On rare occasion U7100 can pull down the data lines. There is a shared data line between the battery, SMC, and ISL6259(U7100). If PPBUS_G3H is 12.56 V, then you probably have a bad battery.

Make sure the issue is no backlight, and not no image!

• Blown backlight fuse rarely if ever happens. This board has a current sensing circuit in place that keeps the backlight fuse from blowing if there is a short to ground on the backlight line.
• Short to ground on backlight output (if backlight fuse blown, check this).
• Trace of backlight output interrupted (can be caused by corrosion, can be fixed with jumper wire)

Example: https://www.youtube.com/watch?v=O0_0YtdwgF0 (Repaired all corrosion including: LED driver replaced, SMC reflow, Thunderbolt chip replaced, screen connector cleaned and connections resoldered, several corroded components in memory area and screen power area replaced, jumper wire for screen backlight output)

• Bad screen/screen cable. If backlight voltage is 49–50 V, bad screen.
• USING WRONG SCREEN! If you use a 2012 or a 2015 screen on a 2013–2014 A1502, IT WILL NOT WORK!

If the screen is shorting the backlight to ground, you can fix the screen if the capacitor/connector on the screen is bad, it just sucks to do. But it is the only option since this screen is no longer available.

You can fix the screen if the capacitor/connector on the screen is bad, it just sucks to do. But it is the only option since this screen is no longer available.

• Bad screen cable
• Screen cable needs reseating (this fixes it a surprising amount of the time)
• Blown L8300
• Bad GPU inside the CPU.

When you find that 5 V is still missing on L8300 and LCD_PWR_EN is missing on U8300, do not chase. 99% of the time this turns out as a no fix, usually bad iGPU or MUX communication issues.

The machine running exceptionally slow with the fans spinning fast denotes a sensor issue. When a sensor is off, and it thinks the voltage/amperage is too high/low somewhere, or that the temperature is too high/low somewhere, it will clock the machine down and cause the fan to run at max RPM. You have to use a tool that reads sensors like hwsensors, or boot into a Linux distribution to check your sensors, then chase down the circuit responsible for that sensor using the schematic/boardview. If all sensors are off, this usually points to an issue with the SMC or PP3V3_S5_AVREF_SMC.

• Bad trackpad can cause sensor issue. Water gets to the trackpad first in many occasions.
• Q5871 corroded, difficult to see without microscope, on edge of board.
• U5870 corroded, on edge of board next to fan where water comes in.

As usual check PPBUS_G3HOT, PPVRTC_G3H, PP5V_S5

PP5V_S4 is 0 V (problem here)

C7320 has corroded pad so U7320 had no input on pin 6 so no Vcore was being produced on one of the power phases.

Redoing the corroded trace with a jumper wire and replacing the U7320 chip solved the problem.

Video: https://www.youtube.com/watch?v=8s7HBtQYcaM

No keyboard backlight

On this video the keyboard backlight connector is destroyed https://www.youtube.com/watch?v=PCJfa73GFOU

Corrosion in U1950 area and corrosion at JTAG connector.

On this video the U1950 chip was replaced and a jumper wire ran, JTAG connector bulldozed off board. U1950 allows other signals and power rails to turn on the computer. Example: https://www.youtube.com/watch?v=yGDURMxwzt8

Corrosion at U1900 RTC (Real Time Clock) circuit

• U1900 and C1910 were removed
• Corrosion was removed
• U1900 and C1910 were restored.
• Example: https://www.youtube.com/watch?v=L8sc8ll7EaA

Measure voltage on inductor L7310 (CPUVR_PHASE1) located just to the left of the CPU. Should be 1.85–1.95 V

If voltage is missing check for corrosion on other side of the board (in the location where the CPU is positioned but on the back of the board) around C1212. Some capacitors including C1212 could be shorted to ground but that isn't the cause of the fault. Clean up the corrosion first. Check for hot parts using voltage injection and a finger.

In this case it was U8030 TPS22924 3.3 V S0 switch that was shorted and removing the part cleared the short. Replace with good part, problem solved. Example video for this repair: https://www.youtube.com/watch?v=C9Qb32XtROE

Note this repair also applies to the A1502 2015 model but the parts will probably have different U locations.