How To Fix Service Battery Macbook Air

1. What is MacBook bombardment not charging upshot?

A MacBook battery not charging problem means that you tin can turn on your MacBook, only the charger will not charge the battery. In other words, your MacBook is mostly working well except for the battery charging part. The following symptoms indicate that you take a MacBook Air or MacBook Pro not charging problem:

1. You get the message "Battery is not charging" in the status menu.
2. You have the message "No battery available" in the status menu.
3. Yous don't take a green light or orange light on the MagSafe connector.
4.  The status menu shows your bombardment is normal and fully charged. Simply if you remove the charger, the MacBook volition plough off instantly.

Many people become confused between "MacBook bombardment not charging" and "MacBook not turning on". A MacBook with battery charging problem tin exist turned on if y'all connect a working charger to it.  On the other manus, a "MacBook non turning on" trouble ways that when you lot press the power button on the MacBook keyboard, no matter you connect a working charger to it or non, you can't run across annihilation on the Mac screen, no chime, no light on the keyboard and no fan-spinning dissonance. In other words, the MacBook has no sign of life at all. If your MacBook can not turn on, run across our article MacBook Won't Turn On? 10 Ways To Fix It.

ii. Why is my MacBook battery not charging?

MacBook battery charging system consists of four components: a charger, a battery, a charging circuit and an SMC scrap. Whatever of these components gone wrong would cause the MacBook Air or MacBook Pro not charging.

1. MagSafe charger or USB-C charger. It delivers power to your MacBook and its battery.
2. Bombardment. It stores power (charging) and provides power (discharging).
3. Charging excursion. It converts the charger voltage to run your Mac and charges the battery.
4. System Direction Controller (SMC).  It controls the behaviour of the charging excursion including start or stop charging the battery.

Faulty chargers, faulty batteries and incorrect SMC information account for the majority of MacBook non charging problems. Fortunately, these faults are easy to fix. Faults in the charging circuit are hard to set and nosotros hash out it in the last department.

If you discover the Bombardment Condition card says Not Charging, and the message disappears later, your MacBook should be fine. You could run across the temporarily Not Charging bulletin for several reasons:

1. You use a depression-ability adopter. The power adapter barely provides enough power to run your MacBook, but not enough power to charge the battery. For example, if you connect a Macbook Air charger (45W) to a 15" MacBook Pro (85W charger required), y'all could get the battery not charging notification. If you plough off the Mac or put it to sleep, the power adapter will start charging the Mac.
2. Safety concern. If you lot connect your Mac to an airline ability adapter, your Mac might not accuse the battery, fifty-fifty if you turn off your Mac or put it to sleep. You can all the same utilise your Mac without draining its bombardment. For safety reason, charging a battery in an aeroplane is considered a hazard task.
3. Running high-performance apps. If your Mac is running high-performance applications such as video editing software and video games, the Mac battery may non be charged. If the apps demand more ability than the adopter tin provide, your Mac will combine the adopter power and battery power to run the MacBook in order to meet the high power demand. This is an Apple design feature to boost operation on demand. If the apps drain the bombardment likewise speedily, y'all may demand to pause the apps and permit your Mac get-go charging the battery. If you switch off the Mac, the adapter will charge the Mac much quicker.
4. Extending battery life. Your battery may drain to 90% or lower before it begins charging again. This is a design feature to extend the life of your MacBook lithium-ion battery. You can turn off battery health management in Energy Saver preferences. Nosotros don't suggest you change the setting unless yous accept a special demand.

3. How does a MacBook accuse its bombardment?

In gild to quickly diagnose and ready the Mac battery non charging issue, you need to know how a MacBook charges its battery. At that place are two types of MacBook chargers: MagSafe charger and USB-C charger. Apple discontinued the MagSafe chargers in 2015-16.

Magsafe Charger

The output voltage of a Magsafe charger is fixed . A MacBook Air charger outputs14.5V. A MacBook Pro charger outputs16.5V, 18.5V or 20V depending on the model.

When you connect a MagSafe charger to the MacBook, the SMC will "handshake" with the info-chip inside the Magsafe connector to place the charger type including voltage output, current output, manufacturer code then on. If the charger meets the criteria, the SMC turns on the green light on the connector. This green light tells you that the SMC has successfully identified a suitable charger for your MacBook.

The SMC will also "handshake" with the info-chip inside the battery to identify the battery type including the working voltage, manufacturer code, current temperature then on. Based on the data received from the charger and the battery, SMC determines whether or non to charge the battery and how much amount of current will use to the bombardment cells.

SMC will tell the charging circuit to outset charging the bombardment if ALL the following atmospheric condition are met:

1. The MagSafe charger has plenty ability to power-on the MacBook and charge the battery at the same time.
2.  The temperature of the battery is normal and the battery is not fully charged.
3.  The charging circuit detects NO over-current or over-temperature.

While the SMC controls the charging excursion to charge the battery, it turns on the orange calorie-free on the connector. The orange low-cal tells you that the charger is currently charging the battery.

When the bombardment is fully charged, SMC will cut off the current flowing into the battery to prevent overcharging the bombardment. The SMC and then changes the light colour to green. This time the green light tells you that the charger has completed the charging chore. The charger at the moment simply provides enough ability to ability on your MacBook if the MacBook is on.

USB-C Charger

The output voltage of a USB-C blazon charger is not stock-still . The USB-C charger volition negotiate with the MacBook to work out an optimal output voltage dynamically. A USB-C charger could output 5V, 14.5V and 20V depending on the state of affairs. For example, a MacBook Pro USB-C charger will output 20V to charge the bombardment. When the battery is fully charged, and the MacBook is off, the USB-C charger will drop the output voltage to 5V.

At that place is no indicator light on the USB-C charger connector to tell you what is going on. But the principle of the MacBook battery charging arrangement is the same, although the communications between the USB-C charger and the SMC are much more complicated.

More for advanced readers: MacBook charging circuit discussion &  MacBook power-on sequences

Armed with this knowledge, yous are prepare to prepare the Mac bombardment not charging trouble now.

4. Set MacBook not charging problem step-by-stride

Many factors could cause the MacBook battery not charging issue. Depending on the cause of the MacBook Pro or MacBook Air not charging issue, the respective solution varies from like shooting fish in a barrel to hard. Nosotros volition discuss the easy solutions commencement and the most difficult one at the end. Some hardware-related problems require specific equipment and(or) spare parts. At the beginning of each department, we will mention the difficulty level of the prepare and equipment and(or) spare parts required for the repair. And so y'all can estimate your successful rate based on your skill. Good luck!

four.one Check charger output voltage

Difficulty level: Beginner

Spare part required: Spare charger will aid

If your MacBook charger is not working, of course it can't charge the battery. So you need to make sure the charger is working fine.

First, y'all demand to make sure that the ability outlet is ok. You can plug in a phone charger or a lamp to the ability outlet, or plug in your MagSafe charger to another ability socket. This simple step lets you know that the power outlet is working or non.

Don't forget to check the power cord connection on the charger. The Apple tree adapter consists of 2 parts: the MagSafe charger and the removable power cord. Make sure you insert the power string to the MagSafe firmly.

Next, inspect both the input and output cable of the charger advisedly, starting at one end and piece of work your way through until the other end. Look out for whatever fraying or tears in the cable. If there are whatsoever flaws similar to the ones mentioned, this is likely to be the problem. Supplant the charger or try another available charger. Believe or not, these simple checks often set the MacBook battery non charging issue.

When you use a spare charger to test the MacBook, beware that there are a few types of MagSafe chargers for unlike models of Mac laptops. The output voltages are14.5V for MacBook Airs, 16.5V and xviii.5V for MacBook Pro, 20V for xv" MacBook Pro with retina screen. The basic rule is that the higher-voltage (therefore higher-power) charger can replace the lower-voltage charger.

In fact, Apple tree uses the same charging IC chip (ISL6259) on the logic board from 2008 to 2015 to handle dissimilar types of MagSafe chargers. This IC fleck will automatically produce the right voltage to power your MacBook and charge the battery. So a higher-voltage charger will non damage your MacBook. Of course, when you buy a replacement charger, purchase the same type of your original one.

Also, the MagSafe one and MagSafe 2 chargers are not exchangeable every bit the size of the connectors are slightly different.

If your MacBook uses Magsafe charger, as long as you can the dark-green light or orangish light on the Magsafe connector, the MacBook charger is working fine.

The MacBook USB-C charger is smarter. Your MacBook will automatically negotiate a suitable voltage output (5V, fourteen.5V and 20V) from the USB-C charger. Yous don't have to worry most the charger type, as long as the charger has the capability to power the  MacBook.

If your MacBook uses a USB-C charger, you lot can purchase a small USB-C ability commitment tester to monitor the behaviour of the USB-C charger shown equally below. Information technology tin can provide information including output voltage, output current and charger temperature. If you get 14.5V from a MacBook Air USB-C charger or 20V from a MacBook Pro charger, the charger is working fine. The photo below shows the USB-C charger is delivering  power of 20.3V and 0.20A to the MacBook Pro.

iv.2 Check charging port and Magsafe connector

Difficulty level: Beginner

Spare part required: None

Inspect the charging port on the MacBook and the MagSafe connector for debris and burned marks. The port and the connector rely on their strong magnetic attraction to hold them together. The charging port tends to concenter small metal items such equally staples and newspaper clips. These foreign objects prevent the connector from close contact with the charging port. The connector could be very warm due to the extra resistor created past the loose contact. In an extreme instance, yous even can run into the electric sparks. If y'all find burn marks on the charging port or the connector, you need to clean them or replace them every bit before long as possible earlier they cause more damages.

If debris is plant in the charging port, you lot can use a toothpick or a pair of metallic tweezers to become it from the port. There is no ability voltage present on the 4 power-pins of the charging port.  The reverse-current protection gate (transistor) on the logic lath prevents the bombardment ability reverse to the port. Yous won't accidentally short the circuit past using a metallic tool to do the cleaning task.

Pay attention to the middle pin of the charging port. Make sure at that place is no film covering the pivot. The SMC uses this pin to communicate with the MagSafe charger. Any thin moving-picture show will cake the electronic transmission, and you lot won't get the green or orange lite even though both your MacBook and MagSafe are working. Use a small sharp pocketknife to make clean the pins then stop up with cotton wool buds with 95% booze.

USB-C ports and plugs are also discipline to clay. Yous can utilise cotton and booze to clean them. Remember to remove the charger from the power outlet before you clean the connectors.

4.iii Reset SMC chip

Difficulty level: Beginner

Spare role required: None

The System Management Controller (SMC) controls the process of MacBook bombardment charging. If the SMC somehow has incorrect data of the MagSafe charger or the MacBook bombardment, the charger volition charge the battery very slowly or even not accuse at all.

Apple started to utilize non-removable batteries in all MacBook models from 2008. Follow these steps to reset the SMC on a MacBook with non-removable battery:

1. Concord the ability button for at least 5 seconds until the MacBook turns off.
2. Connect the MagSafe charger, agree Shift-Command-Option on the left-manus side keyboard and the power push button simultaneously for 10 seconds.
3. Release all the keys.
4. Press the power button to turn on your Mac. Now you accept successfully reset the SMC.

Resetting the SMC on MacBooks with removable-batteries is elementary.

1. Concur the power button for at least five seconds until the MacBook turns off.
2. Remove the ability adaptor and the battery from the MacBook.
3. Concord the power button cardinal for 5 seconds to belch any remaining electric energy in the capacitors of the SMC circuit. Alternatively, you tin await for a few minutes until the capacitors discharge naturally.
4. Re-install the battery back to your MacBook. Now you have successfully reset the SMC.

If resetting the SMC cannot solve your MacBook won't charge problem, reset the PRAM as discussed beneath.

iv.4 Reset non-volatile random-access retentivity (NVRAM)

Difficulty level: Beginner

Spare part required: None

NVRAM contains user-defined data such as screen brightness, keyboard backlight setting and sound volume setting. If this data is corrupted, your MacBook won't charge the battery or accuse extremely boring.

To reset the NVRAM, follow these steps:

1. Concord the ability button for at least 5 seconds until the MacBook turns off.
2. Printing the power push button to turn on the MacBook.
3. As soon equally you hear the chime or see any lite on the screen, agree Control-Choice-R-P 4 keys simultaneously until the MacBook restarts.
4. Release all the 4 keys.
5. After reboot, y'all have reset the NVRAM.

If you still have the MacBook not charging issue, move on to the adjacent level – hardware faults troubleshooting.

4.five Cheque bombardment connector

Difficulty level: Basic

Spare part required: None

All pre-2016 MacBooks use 9-pin connectors to connect the batteries to the logic boards. Pin 6 is used for bombardment detection. When you lot connect a battery to the logic board, this pin volition send a signal to the battery internal "smart" circuit to turn on the "safety switch" called MOSFET. Therefore the electric current can menstruum in and catamenia out of the battery freely. This safety blueprint prevents accidentally shorting the battery terminals and causing damage to the battery or even fire.

Also, SMC uses pin 4 and five to communicate with the bombardment. Every bit all these pins 4, 5 and 6 carry low-voltage electronic signals, any of them slightly loose contact will cause MacBook not charging.

Make sure there is no dirt or liquid on the connector and socket. Use cotton fiber buds with at least 95% alcohol to clean the pins and reconnect the connector firmly.

iv.6 Replace the faulty battery

Difficulty level: Bones

Spare part required: Bombardment for your MacBook model

The SMC uses a pair of data lines chosen SM-jitney to communicate with the battery. SMC besides uses current-sensing circuits to monitor the real-time electric current coming in or out of the battery. Based on this data, your MacBook displays the battery info in the notifications section.

There are five battery notifications:

1. Normal
2. Service Battery
3. Replace Before long
4. Replace Now
5. No Battery Available

Apple'southward certificate has merely defined the "Normal" and "Service Battery" messages, leading to a lot of misunderstanding even misleading information of "Supersede Before long" and "Replace Now" messages. We volition clarify these letters here.

"Normal" means your battery is fine. Your battery retains more than 80% of the original chapters.

"Service Battery" means the bombardment has degraded to less than eighty% of the original capacity. Usually, the battery still tin last for two or three hours of normal usage. You may choose to replace the battery merely it is not urgent. The battery could last for a year or 2 if yous connect your MacBook to the charger about of the time to reduce battery usage.

"Replace Soon" means you need to arrange a battery replacement before long. Apple tree has non specified the criteria of this message. Our test data shows that this bulletin ways your battery retains less than nearly 50% of the original capacity. If you even so utilise the battery, keep an eye on it and make sure the battery is non bloated. Below is a bloated battery in a 13" MacBook Pro. An inflated battery volition put pressure on the example, touchpad and even the logic board.

If yous notice that your touchpad cracks or pops up, as shown in the photo below, you near likely take an expanded battery. You need to supplant the bombardment immediately to preclude more harm.

"Supervene upon At present" means that the SMC still tin communicate with the battery, only very petty or even no current can flow in or out of the bombardment. If you disconnect the charger, the MacBook will shut off at once. The battery finally comes to the cease of its life.

"No Bombardment Available" with a cantankerous mark on the bombardment icon as on the photo below:

It ways the SMC cannot communicate with the battery at all. Your battery is either completely expressionless or not continued to the logic board properly. Usually, replacing the battery tin solve the problem. Only from time to time even when you replace the battery, y'all still get the "No Bombardment Bachelor" message. This symptom is a strong indication that your logic board is faulty. You need to get your logic board repaired to solve the MacBook not charging problem.

If your battery is faulty, you can get the battery replaced past a service provider or replace the battery yourself.  When you guild the bombardment online, quote the bombardment model instead of the MacBook model to ensure you will get the right battery for your MacBook. For example, xv" A1398 MacBook Pro 2012 uses battery model A1417.

When you replace the MacBook battery yourself, use your fingernail or a plastic stick to remove the battery connector from the logic lath. Never use a metallic screwdriver. Otherwise, you may curt circuit the battery or even worse, destroy the SMC past sending the 12V battery power straight to it.

The bombardment is attached to the MacBook example by screws in Pre-2013 MacBook Pro and Pre-2018 MacBook Air. You merely remove the screws and disconnect the battery connector from the logic board. If you purchase replacement batteries online, most of them come with a handy screwdriver.

Apple chooses to glue the batteries to the MacBook example in 2013 onwards MacBook Pros and 2018 onwards MacBook Airs. Removing the glued bombardment from the MacBook case is a fleck difficult for beginners. Pay attending to the defended logic board. You don't want to knock off some chips on the logic board and destroy information technology.

The battery connection in newer MacBooks with USB-C charging ports is unlike. The power lines and data communication lines are no longer on the same connector. Instead, the power lines ("+" and "-" terminals) are connected to the logic board secured by a T-five screw to provide meliorate contacts. The data lines are connected to the logic board via a flex cable.

The correct process to remove this type of battery is crucial. You need to remove the flex cable from the logic board first. Then utilise a T-5 screwdriver to remove the spiral and disconnect the ability terminals. Once you remove the data flex cablevision, the smart bombardment will turn off the "condom switch" inside the battery and there will be no power on the ability terminals.

If the data flex cablevision is not working due to loose contact or liquid impairment, you volition get the "No Battery Available" message.

IT-Tech Online is a leading Mac repair specialist in Commonwealth of australia. We are more than happy to assist you if you cannot set up the issues yourself. We offering competitive prices for MacBook battery replacement. Please contact us . Our experienced staff will call you to assess your situation and provide a free quote for you.

four.7 Check battery indicator circuit

Difficulty level: Bones

Spare part required: None

The pre-2013 MacBook Pro comes with a bombardment status indicator. You can button the button to see how much percentage the battery retains the power. This indicator shares the same circuit with which the SMC uses to communicate with the battery. If the indicator is faulty, especially after being exposed to water, the SMC cannot talk to the battery, therefore reports no battery establish.

Fixing this trouble is easy. Yous tin can replace the indicator, or just unplug the indicator cable if yous decide not to use the indicator function any more than.

4.8 Cheque faulty DC-in Board

Difficulty level: Intermediate

Spare part:  MacBook Pro DC-in board

The battery on MacBook Pro non charging could exist acquired by a failed DC-IN lath in the Pre 2013 Mac. The SMC uses the middle pin (pin 3) to talk to the MagSafe charger. There is a diode on the  DC-IN lath connecting pin 3 to the basis to protect the SMC excursion.

If there is a higher voltage accidentally applied to pin 3, for instance, power surge or pivot 2 (sixteen.5V – xviii.5V) shorted to pin 3, the diode will short this high voltage to the ground to forestall the defended SMC being damaged.

If the diode has been damaged, the SMC cannot talk to the MagSafe charger so you won't go the green lite. Of grade, your MacBook won't charge the bombardment as there is no power coming from the charger.

Fixing the problem is easy. You lot can purchase a DC board online for a few dollars. Depending on the MacBook model, you may need to remove the logic board to disconnect the DC board cable.

If you need to remove the logic board, pay attention to the fan connector. The fan connector is very easy to skin off. Repairing the fan connector requires micro-soldering skill and adds actress cost to your repair bill.

You fifty-fifty can remove the diode, and the DC board will piece of work again. But bear in mind that there is no protection to your SMC excursion in instance a power surge occurs.

four.ix Supervene upon faulty I/O board cable

Difficulty level: Intermediate

Spare role:  MacBook I/O board cable

There is a cable connecting the logic board to the I/O board. The SMC uses the "one-wired" excursion to talk to the MagSafe charger. This "one-wired" signal needs to laissez passer the cable to the I/O board and finally reaches the charger.

If the cable is loose, the "one-wired" signal will not pass to the charger and so you won't get the greenish low-cal on the charger connector and your MacBook won't charge the battery.

Remove the cable,  clean the cablevision and 2 connectors on the logic board and the I/O board with a toothbrush and  95% alcohol. Call up the cablevision direction. If you lot connect the cablevision reserved, y'all may damage the MacBook.

The cablevision is prone to liquid damage. If you lot spill h2o on your MacBook Air right earlier you get the MacBook not charging result, you most likely have a corroded cable and (or) connectors.

You tin get the I/O lath cable for a few dollars online. If your I/O lath is faulty, y'all besides can get it for less than 50 bucks.

4.ten Repair the faulty reverse-protection excursion

Difficulty level: Advanced

Equipment required: Hot air gun rework station

If yous connect an Apple original MagSafe charger to the MacBook, y'all can't see whatever green or orange light on the connector. But if you plug in a third-party charger to the MacBook, y'all can encounter the green or orange light and your MacBook battery is charging the battery perfectly. This unique symptom indicates that you have a faulty reverse-protection excursion on the logic board.

The reverse-current protection excursion is designed to prevent the internal battery power "contrary" out from the bombardment to the charger. If the reverse-current protection circuit has electric current leakage, fifty-fifty every bit little as a few milliamps, the original MagSafe charger will detect the leakage, therefore, shut off the output.

On the other hand, the 3rd-political party charger has no leakage detection role; therefore, go along to output as usual.

At present you have two options. Y'all can keep using the tertiary-party charger every bit the leakage does not touch on the operation of your MacBook. The second option is to supersede the reverse-current protection MOSFET. You demand a hot air gun rework station to perform the task.

5. Understand the principle of MacBook battery charging circuit

We are going to expect at some case studies at expert-level.  Fully understanding the principle of the MacBook charging circuit is the cardinal to success. Here we have  MacBook Pro schematics 820-4924A for study.

File name : MacBook-Pro-2015-Battery-connector.pdf

File proper name : MacBook-Pro-2015-Charging-excursion.pdf

1. When a battery is continued to the logic board, a 10KΩ resistor R7050 is connected to the battery connector J7050 pin 15. The smart battery internal circuit detects the presence of the 10KΩ resistor, and so opens the bombardment internal MOSFET to output the battery voltage. In other words, the battery output volition remain close unless a 10KΩ resistor is detected. This is the safety feature of the smart battery.
2. The battery voltage PPVBAT_G3H_CONN is about x-12.6V depending on whether the battery is fully charged or non. PPVBAT_G3H_CONN passes the internal diode of Q7155, charging electric current sensing resistor R7150, fuse F7140 and becomes PPBUS_G3H power track.
3. At present we have the PPBUS_G3H power track. Bear in mind that this voltage is passed from the diode inside the MOSFET Q7155. Q7155 is not open still. And then at this moment, this temperate PPBUS_G3H is a "weak" ability rail and only can provide a very pocket-sized amount of current. This is a great condom characteristic of Apple logic board blueprint. It prevents the battery from exposing due to overheating if in that location is a brusk on the logic board. This temperate power rail is powerful plenty to power a PMIC to create an e'er-on power rail PP3V42_G3H.
4. The PP3V42_G3H power runway volition power the System Management Controller (SMC) and ability management IC U7100. SMC volition read the code stored in the chip within the battery via a pair of SMBus: SMBUS_BATT_SCL and SMBUS_BATT_SDA. This code contains information such as battery voltage, charging status, battery capacity, charging circle counts, temperature and then on.
5. If the battery bank check is ok and it has plenty ability to ability the system, SMC volition communicate with the charging PMIC U7100 via a pair of SMBUS: SMBUS SMBUS_CHGR_SCL and SMBUS_CHGR_SDA. Then U7100 will output CHGR_BGATE to open MOSFET Q7155. Now nosotros accept a stable, "total power" PPBUS_G3H power runway fix for use by the laptop.
6. When we press the power button on the keyboard, the SMC volition power up the Apple laptop using the battery along.
7. When a power adaptor is connected to the MacBook, U7100 will create its own PPBUS_G3H from the power adaptor. U7100 outputs CHGR_BGATE to control the Q7155 to accomplish battery charging or discharging co-ordinate to the bombardment status and the applications we are running on the laptop. All these functions are governed by the SMC.

half dozen. Advanced MacBook repair (battery not charging) - example study

Difficulty level: Proficient

Equipment required: Hot air gun rework station, multimeter

This is a xiii" MacBook Pro 2015 with retina screen. The laptop works fine when a  charger is connected but shuts downwardly immediately when the charge is removed. A "service battery" message is displayed on the notification department and in that location is an orange light on the charger connector. The customer said the laptop battery had been replaced by some other computer shop simply the laptop is withal not charging. Initial inspection shows no evidence of h2o damage or corrosion.

Connect the MacBook to our metered ability supply. The current drawn from the ability supply is 0.027A in standby mode. Supplant the bombardment with a known working battery. The current drawn is withal 0.027A. This confirms that the trouble is in the logic board. How exercise nosotros fix information technology?

Nosotros remove the logic board from the case and inspect it nether a microscope. There is no evidence of liquid damaged at all. The schematics for this MacBook Pro is 820-4924A.

1. Measure bombardment connector J7050. The figures of pivot xiii and xiv  SMBUS clock line and information line are 0.508 and 0.509 respectively in diode mode. It means the bombardment communication bus to SMC should be fine. Measure pivot xv battery detection SYS_DETECT_L. The figure is 9.eight KΩ. It matches the R7050 figure on the schematics. So the battery detection circuit should also exist fine.
2. Inspect U7100 charging circuit PMIC (Power Management Integrated Circuit). At that place are no burned marks or burned components. Measure the value of the resistors between U7100 pin 27 and 28 CHGR_CSI_R. The figure is 22Ω, ok. Measure the value of the resistors between pin 17 and 18  CHGR_CSO. The figure is ii.9Ω, ok. The charging circuit seems ok.
3. Mensurate Q7155  MOSFET in diode style. Pin 5 to 3 is 0.472, ok. Pivot 3 to 5 is an open up line, very good. Both pin 5 and pin 3 to pin one are all open line, excellent. All these measurements indicate the Q7155 is working fine.
4. At that place is no obvious faulty component found. This logic board is not easy to set up. Nosotros take to rely on intelligent guesses based on past feel – the "endeavour and error" approach.  The U7100 (charging circuit ability management IC) is the showtime doubtable. Let's replace it. The bombardment is still not charging afterward replacing U7100. Nosotros have just killed an innocent charging chip.
5. The second suspect is Q7155. This MOSFET is used to command the bombardment charging electric current. Let's supercede it. The problem remains after replacing Q7155. We accept only killed another innocent bit. This guess-by-experience method does not work in this instance, manifestly.  Nosotros have to stop this problem-solving approach before the repair job turns into a nightmare.
6. It is fourth dimension to rethink our strategies. It is hard to become the charging circuit to charge the bombardment in this case, just nosotros may work the other way effectually. We may use a good bombardment alone to power the laptop without connecting to the power adaptor, then we can follow the bombardment discharging electric current flow to pinpoint the faulty components. Let's do information technology.
7. Connect the logic board to a expert working gild bombardment and measure the voltage of Q7155. The voltage on pin 5 and pin iii drops from 12.4V to 0V and keeps repeating. The voltage on pin 4 drops from five.2V to 0V and repeats in a circle. In that location is no shorted circuit on pin 5, pin 3 and pin 4. This measurement consequence confirms that the Q7155 MOSFET is working perfectly. For some reason, information technology opens for 1 or 2 seconds and then closes.  It is why the voltage rises upward to12.4V then drops to 0V repeatedly. We have institute the problem now, but why did the Q7155 not remain open?
8. Q7155 pin v connects to the battery positive terminal directly. Dropping voltage in pin 5 ways the bombardment is cutting the output voltage by itself. If the battery is proficient, and there are no short circuits on the load side, so the only affair that can make the battery shut off by itself is the bombardment detection circuit. This circuit is very simple, consisting of only one 10KΩ resistor R7050.
9. We measured this resistor R7050 an hour agone and the figure was ix.8KΩ. Let's measure information technology again fifty-fifty though it still looks skilful with no sign of damage. This fourth dimension the figure is 5.9KΩ. This resistor has an intermittent fault! This intermittent mistake fabricated us waste matter one hour and kill two innocent chips. If the resistor remains at five.9KΩ all the time, nosotros could take fixed the trouble in v minutes. The intermittent faults are the most hard faults to bargain with.
10. Replace R7050 with a good 10KΩ resistor and we get a working laptop.

How To Fix Service Battery Macbook Air,

Source: https://www.it-tech.com.au/how-to-fix-macbook-battery-not-charging-issue/

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