A1466 2013-2014 13” MacBook Air

Logic board part number: 820-3437

{|class="wikitable" ! style="text-align:left;"| Problem ! Solution Example: https://www.youtube.com/watch?v=z_N23fNAgpw (U7090 replaced, several capacitors replaced and probe points revived) Thermal camera showed U4500 was bad due to liquid damage
 * Random shutdown
 * Visual inspection: can be caused by corrosion at U7090 (makes PP3V42_G3H), corrosion at BIOS chip, several bad probe points and capacitors
 * Visual inspection: can be caused by corrosion at U7090 (makes PP3V42_G3H), corrosion at BIOS chip, several bad probe points and capacitors
 * Boot Loop
 * from 10mA to 550mA several times then settling at 350mA
 * from 10mA to 550mA several times then settling at 350mA
 * No green/orange light on charger
 * PP3V42_G3H missing due to short to ground, bad D7012, bad U7090, R7080 corroding away, bad C7560
 * DC in cable (821-1722) corroded, and connector traces for SYS_ONEWIRE, SMC_BC_ACOK, and PP
 * DC in board has corroded traces around TC7SZ08AFEAPE or MAX9940 for onewire circuit (check onewire circuit diagram on older boards like 820-2530 this is present on the DC in board now of the *A1466/A1465/A1369/A1370 Macbook Air)
 * SMC_RESET_L low due to corroded R5115 pull-up resistor, bad U5110, or bad U5000
 * SMC_RESET_L low due to bad SMC
 * SMC_RESET_L low due to corroded R5115 pull-up resistor, bad U5110, or bad U5000
 * SMC_RESET_L low due to bad SMC

REMEMBER: SMC is not on if PPBUS_G3H is 8.15V instead of 8.55V (SMC needs to communicate with U7100 to tell it over SMBUS line to raise PPBUS_G3H from 8.15V to 8.55V). Example: https://www.youtube.com/watch?v=rAHLji04zOo (fixed by running jumper wires to bypass corroded probe points) Example: https://www.youtube.com/watch?v=1CqYQWdo6XE Power Rails PPBUS_G3H (8.6V), PP3V42_G3H (3.42V), PMDSW_POWERGOOD (3.3V), PP5_VS5 (5V) were checked. Corrosion at U1900 (Real Time Clock RTC). RTC chip was replaced and this fixed the computer. If PM_SLP_S4_L missing, we need to check these
 * No power, PM_SLP_S4_L is missing, draws 2324mA of current
 * U1950 is corroded and you can't see it.
 * Corrosion on probe points for SPI ROM U6100 area
 * U1950 is corroded and you can't see it.
 * Corrosion on probe points for SPI ROM U6100 area
 * Bad clock chip U1900
 * Corrosion on RTC pull-up resistors R1300 to R1303 (or C1300/C1303 shorted to ground)
 * If you remove R8111 and PM_SLP_S4_L comes back, it's most likely dead CPU, check for corrosion around RAM area and if none then most likely dead CPU.
 * 1. PPVRTC_G3H
 * 2. RTC_RESET_L
 * 3. PCH_SRTCRST_L
 * 4. PCH_INTVRMEN_L
 * 5. PCH_DSWVRMEN_L
 * 6. SYSCLK_CLK32K_RTCX1
 * 7. PP3V3_S5
 * 8. PM_DSW_PWRGD
 * 9. PP3V3_SUS
 * 10. PM_BATLOW_L
 * 11. PM_RSMRST_L
 * +1. PM_PWRBTN_L


 * No power, 0mA draw or 250mA draw, PPBUS_G3H missing
 * Short to ground on PPBUS_G3H. Blown fuse F7140 for PPBUS_G3H (if it draws 0mA), or good fuse (250mA), bad tantalum capacitor on PPBUS_G3H.
 * No power, power cycling 200mA / 20mA
 * Check U8005 and C8005
 * No backlight
 * 0V bad backlight fuse, short to ground inside connector/inside screen
 * 812V feedback trace to LP8550 (U7701) burned out, see example: https://www.youtube.com/watch?v=xMhu4WyQZAA, or BKL_EN missing.
 * 1920V BKL_PWM low, or SMC_LID low due to bad DC in board. SMC_LID also comes from the trackpad, so a bad trackpad can cause this.
 * 1920V Bad/corroded U7701/8550 (and missing resistor), example (820-3437): https://www.youtube.com/watch?v=j7aLzsxxI5M
 * 3950V screen backlight cable disconnected inside screen after DIY repair, bad connector, bad screen
 * No power, PPBUS_G3H 4V instead of 8.55V
 * Bad U7100, blown R7021/R7022
 * Bad U7000, blown R7120/R7121/R7122 or blown R7150/R7151/R7152 (24mA charger draw)
 * Any board-level issue at all.
 * Look at J6100, and feel guilt-free in killing it.
 * Keyboard and trackpad not working
 * Bad trackpad cable or bad trackpad. (first check with working keyboard and trackpad)
 * Bad R4830 (0 resistor). Example: https://www.youtube.com/watch?v=ocF_hrr83Oc (Resistance of R4830 (0 resistor) was 37)
 * SMC_RESET_L low, but board works outside of case
 * Bad trackpad. Trackpad controls SMC_LID and SMC_RESET_L, so trackpad can mess with backlight. Louis explains here
 * Battery not recognized with X
 * Firstly, try a known good battery before assuming it is the board!
 * Keyboard and trackpad not working
 * Bad trackpad cable or bad trackpad. (first check with working keyboard and trackpad)
 * Bad R4830 (0 resistor). Example: https://www.youtube.com/watch?v=ocF_hrr83Oc (Resistance of R4830 (0 resistor) was 37)
 * SMC_RESET_L low, but board works outside of case
 * Bad trackpad. Trackpad controls SMC_LID and SMC_RESET_L, so trackpad can mess with backlight. Louis explains here
 * Battery not recognized with X
 * Firstly, try a known good battery before assuming it is the board!
 * Bad trackpad. Trackpad controls SMC_LID and SMC_RESET_L, so trackpad can mess with backlight. Louis explains here
 * Battery not recognized with X
 * Firstly, try a known good battery before assuming it is the board!
 * Firstly, try a known good battery before assuming it is the board!

If PPBUS_G3H is 8.15V, SMC is not communicating properly with anything because its data line is blown. Check pull-up resistors on data line, see what may be pulling it down, most likely bad SMC (U5000).


 * Not powering on but is charging
 * Bad / corroded clock chip
 * Bad / corroded clock chip
 * Bad / corroded clock chip

Take note that on this board if you remove the battery, when turning on the board you should expect the fan to turn on/off/on/off/on. If you have a problem with the clock the fan turns on continuously. Example: https://www.youtube.com/watch?v=lHJe8g52rSo
 * Braindead
 * Corrosion under U1930 on pin 6
 * Bad SMC
 * Some random issue you will never figure out; cry
 * Smoke coming from SSD connector
 * Replace SSD connector on the board and check of data pins are shorting to ground.
 * PP3V3_S0 pin might be shorting to ground on adjacent ground pin on the SSD, of so, insulate both pins. This might make the SSD work long enough to remove data.
 * USB issues
 * For left side USB, try new DC in board/DC in cable
 * For right side USB issues, check L4600/U4650 area. L4600 can be open, or U4650 shorted.
 * PP3V3_S0 pin might be shorting to ground on adjacent ground pin on the SSD, of so, insulate both pins. This might make the SSD work long enough to remove data.
 * USB issues
 * For left side USB, try new DC in board/DC in cable
 * For right side USB issues, check L4600/U4650 area. L4600 can be open, or U4650 shorted.
 * For left side USB, try new DC in board/DC in cable
 * For right side USB issues, check L4600/U4650 area. L4600 can be open, or U4650 shorted.

Example: https://www.youtube.com/watch?v=OwiKfiG7Aas
 * Not powering on
 * Corrosion around JTAG connector and 5V regulator circuit.
 * Corrosion around JTAG connector and 5V regulator circuit.

PRAM needs to be reset. Example:https://www.youtube.com/watch?v=IVgKJF_dIy0
 * JTAG connector was bulldozed off the board
 * The 5V regulator chip TPS51980 (U7501) and surrounding area was corroded. Corroded components were replaced, and this fixed the problem.
 * Check for PP5V_S5 and PP5V_S3 and PP5V_S0.
 * If PP5V_S0 is not present, check PP5VS0_EN
 * If not present, trace back to U8180, see if present. If not, short PP3V3_S5 to PM_SLM_S3_BUF_L to turn on S0 enables, like in example
 * When MacBook boots, reset PRAM and remove short


 * You think PPBUS_G3H is 8.55V
 * You measured the right side of the fuse, not the left side of the fuse, because you are right handed and keep the red probe of your multimeter in your right hand. Had you measured the left side of the fuse, you'd realize the fuse is blown, likely due to a short circuit. You are probably off in the wilderness, hunting why your PP3V3_S5 and PP5V_S5 are missing, before you even have PPBUS_G3H... we've all been there.
 * You measured the right side of the fuse, not the left side of the fuse, because you are right handed and keep the red probe of your multimeter in your right hand. Had you measured the left side of the fuse, you'd realize the fuse is blown, likely due to a short circuit. You are probably off in the wilderness, hunting why your PP3V3_S5 and PP5V_S5 are missing, before you even have PPBUS_G3H... we've all been there.

Example: https://www.youtube.com/watch?v=-rok8h1ZRH4 (820-3437 logic board repair with new video format) No liquid damage, the U7400 chip has a 5V input on pin 12 and a 1.5V output on pin 2.
 * Laptop does not power on
 * Look for corrosion on the U7400 chip on the logic board and replace it
 * Look for corrosion on the U7400 chip on the logic board and replace it


 * No Camera (Please do not fix unless required)
 * Different issues
 * Corrosion near U1900. The caps above U1900 go to the camera and U1900 regulates a signal going to the webcam. Corrosion on either can cause no camera. You should replace anyways if it's corroded so this can fix your issue.
 * Corrupt BIOS/bad ME region. If the ME is not cleaned properly or the BIOS dump is not proper, webcam can cease working. Flashing BIOS with a clean ME region can fix the issue.
 * Bad U3900 or Camera RAM. Usually this happens from liquid, but it can happen randomly too. First step is to check for a short on the coils next to U3900 (1v2 CAM, 1.8 CAM etc.). If you have a short on any of these coils, 99% of the time U3900 is the cause and replacing it with a GOOD chip will fix the issue. If no short, you are in rabbit hole territory. You can replace U3900 or the camera RAM IC to fix the issue, but it is not always successful. There is the chance a board trace is broken internally. I would say success rate is around 80% but it's not a fun repair. You can use the camera IC from any donor board that matches it (same chip on 2017 13" Pro board, all Air boards and some Retina boards). As long as it's the same chip, it will work (no programming). Would HIGHLY advise using the ceramic (black) version NOT the flip chip (green) version. Way too easy to kill the chip when reballing green version.
 * Bad U3900 or Camera RAM. Usually this happens from liquid, but it can happen randomly too. First step is to check for a short on the coils next to U3900 (1v2 CAM, 1.8 CAM etc.). If you have a short on any of these coils, 99% of the time U3900 is the cause and replacing it with a GOOD chip will fix the issue. If no short, you are in rabbit hole territory. You can replace U3900 or the camera RAM IC to fix the issue, but it is not always successful. There is the chance a board trace is broken internally. I would say success rate is around 80% but it's not a fun repair. You can use the camera IC from any donor board that matches it (same chip on 2017 13" Pro board, all Air boards and some Retina boards). As long as it's the same chip, it will work (no programming). Would HIGHLY advise using the ceramic (black) version NOT the flip chip (green) version. Way too easy to kill the chip when reballing green version.