Macbook Air Can Not Turn on

1. Symptoms of MacBook not turning on

When you press the Power button or Touch ID button on your Mac, if you don't see any images, video, or visuals of any sort on your display, if you don't hear a startup chime, and if you don't hear any fan or spinning drive noise, then most likely your MacBook is not turning on. In other words, your Mac has no sign of power at all.

If your MacBook Air or MacBook Pro won't turn on after a liquid spill, see our article Spilled water on a MacBook Air or MacBook Pro, what to do now?

If your MacBook won't start up properly, you only see a question mark folder flashing in the centre of your MacBook screen, see our article How to fix the Mac Question Mark Folder issues

If your computer only works with the adapter plugged in, you have a MacBook not charging issue. Check out our article 12 Ways to fix MacBook battery not charging issue

2. Why is your MacBook not turning on?

A MacBook consists of the following components: a screen, keyboard, touchpad, battery, SSD drive and a logic board. Any of these components gone wrong could cause your MacBook won't turn on.

From the moment you press the power button or Touch ID button, to the MacBook displaying the image on the screen, your MacBook has gone through a series of complicated power-on events. The System Management Controller (SMC) governs the entire MacBook power-on process.

Once the SMC detects that you have pressed the power button, the SMC will co-operate with the Intel chipset to create a series of "mini power supplies" of different voltages (e.g. 5V, 3.3V, 1.2V, 1.8V, etc.) in a precisely defined sequence. These "mini power supplies" will power your Mac's memory, hard drive, CPU, Wifi, keyboard, trackpad and screen.

If the SMC has not received power, or failed to function, or failed to create the required "mini power supplies", your MacBook won't turn on.

For deeper technical details of the MacBook power-on process, see our article How does my MacBook power on?

3. Fix Mac not turning on problem step-by-step

There are lots of reasons why your Mac won't turn on. We'll run through various checks, tips and tactics to get your Mac back to work again.In the last section, we will show you how professionals repair Mac computers in the workshop and the resources and equipment used.

3.1 Check for any faulty external devices

If your Mac detects the accessories attached to it have short circuits or draw an unusual amount of current from the Mac, the SMC will cut short the power-on process. This is a safety measure to protect your Mac. You can easily rule out if any device is the culprit.

Unplug all the accessories attached to your Mac including printer cable, USB hub, external USB hard drive, HDMI cable, and Mini display cable, even your Magsafe or USB-C charger. In other words, you just let your Mac stand alone. It could be one of your peripherals causing your MacBook Pro or MacBook Air not turning on.

Occasionally, this simple step would fix the "Mac doesn't turn on" problem.

3.2 Reset the SMC or T2 chip

The SMC is responsible for receiving your action (press power button) then starts and manages the entire power-on process. You may consider the SMC as a tiny computer running a tiny operating system and the software sometimes could go wrong. If this happens to your MacBook, you need to reset the SMC.

You will NOT lose any data in your hard drive by resetting the SMC.

Follow these steps to reset the SMC on a MacBook with non-removable battery:

1. Press and hold the power button for 10 seconds to ensure your Mac returns to its OFF state.
2. Connect the MagSafe charger; hold Shift-Control-Option on the left-hand side keyboard and the power button simultaneously for 10 seconds.
3. Release all the keys.
4. Press the power button to turn on your Mac. Now you have successfully reset the SMC.

Apple integrated the SMC chip into the Apple T2 Security chip starting from 2018. Follow these steps to reset a MacBook with a T2 chip:

1. Press and hold the power button for 10 seconds to ensure your Mac returns to its OFF state.
2. Press and hold these 3 keys for 7 seconds: Control, Option keys on the left-hand side and Shift key on the right-hand side.
3. Then press and hold the power button as well. Now keep holding all four keys for another 7 seconds, and then release all four keys at the same time.
4. Wait a few seconds, and then press the power button to turn on your Mac.

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

1. Press and hold the power button for 10 seconds to ensure your Mac returns to its OFF state.
2. Remove the power adaptor and the battery from the MacBook.
3. Hold the power button key for 5 seconds to discharge any remaining electric energy in the capacitors of the SMC circuit. Alternatively, you can wait 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 SMC reset can't fix the problem, go on to the next step.

3.3 Check for a flat battery

If you haven't used your MacBook for a long period of time or you have an aged or a swollen battery shown as below, the battery could have been completely discharged, causing your MacBook not to turn on.

The pre-2012 MacBook models have a battery check button and a battery status indicator on the right-hand side of the case. Push this button. If you don't see any light, then you have a flat battery.

You need to make sure your MacBook is receiving power from either the MagSafe or USB-C charger. Check if the power cable is undamaged and securely plugged into your Mac and a working electrical outlet. If you're not sure about the outlet, test it with a lamp or a mobile phone charger.

Use the correct power adapter for your MacBook model to charge the MacBook for about 5 minutes. If possible, try to use the original power adapter that came with your Mac.

If the flat battery causes your MacBook Air or MacBook Pro not turning on, most Macs will power on automatically if you connect a working charger to it. However, there are some models of MacBooks that require a minimum battery power before the Mac can turn on. So wait for 5 minutes. Let your charger top up the battery above the minimum level.

If you can see a green or orange light on the MagSafe connector, it means both your charger and the SMC in your MacBook are working now. The SMC has successfully communicated with your charger and then turned on the light. You may try another charger if you don't have a light on the connector.

After 5 minutes, press the power button to see if your MacBook can turn on. If your Mac still won't turn on, or if you don't have a light on the MagSafe connector, go on to the next step.

3.4 Perform a power cycle

A MacBook has three major states: Off, Sleep and On. Performing a power cycle means you force the MacBook return to Off state.

In a pre-2013 MacBook Pro, there is a sleep indicator on the front edge of the case as shown below. When the MacBook enters to sleep mode, this sleep indicator light will flash. Apple removed the sleep indicator in the recent models. For these newer machines, if you can't see anything on the screen, it is difficult to tell what state your MacBook is currently in.

If your MacBook gets stuck in the Sleep state for some reasons, your MacBook will not respond to normal wake-up signals such as opening the lid, pressing the power button or clicking the touchpad. You need to force the MacBook back to Off state by performing a power cycle.

Press and hold the power button for 10 seconds then release the button. Now you have forced the Mac returning to Off state. If you have a spinning hard drive in your Mac, you may hear a squeak as the hard drive power is forcibly cut. If your MacBook has an SSD drive, you won't hear anything.

Now you know your Mac is in Off state. Press the power button again to see if your Mac can turn on.

If performing a power cycle can't fix the problem, go on to the next step.

3.5 Check for a faulty screen

When you see nothing on the screen, you may think that your Mac won't turn on. But that is not always the case! Your Mac may be ON already; only the screen is not working. Therefore, it is vital to double-check any signs of power including sounds and lights to avoid a misdiagnosis.

Check for sounds

Do you hear a startup chime? If you do, your MacBook is already on. Wait for 1 or 2 minutes to check if there is any display on the screen, even a quick flashlight. If you don't see anything on the screen, your Mac most likely has a screen problem. This is not good news as the screen is one of the most expensive components next to the Apple logic board.

Pick up the MacBook; place the vent holes (between the two screen hinges) near your ear. Do you hear any noise from the fan, mechanical hard drive or super drive? Do you feel any air coming from the vent holes? If you hear the noise or feel the air movement, your Mac is on and your Mac has a logic board problem. Your Mac has already started to turn on but somehow got stuck in somewhere.

Check for lights

If you don't see anything on the screen, shine a flashlight through the Apple logo on the back of your screen. If you can see a dim image, press the screen "brightness up" button on the keyboard a few times to increase the screen brightness. If you still get the dim image, you have a screen backlight problem. The screen backlight problem could be caused by a faulty screen or a faulty logic board.

Press the keyboard backlight "brightness up" button a few times, if you can see the keyboard backlight, your Mac is ON already. You may have a screen problem.

Press the Caps Lock key, if you can see the light on, your Mac is running. You may also have a screen problem.

Connect an external monitor to your MacBook via a mini display port, thunderbolt port or HDMI port. If you have a display on the external monitor, you definitely have a faulty screen.

3.6 Check for a faulty RAM

If you hear repeating beeps from the Mac, your Mac could have RAM faults that are causing your Mac to not turn on.

If you hear one beep, repeating every five seconds, it means your Mac can't detect any RAM. If you recently replaced or upgraded your computer's RAM, check to see if it was installed properly.

If you get three successive beeps, then a five-second pause and keep repeating, your Mac RAM doesn't pass a data integrity check. If you recently replaced or upgraded your computer's RAM, check to see if it was installed properly. You also can try different brand names of memory modules.

If you have a MacBook Air or a MacBook Pro 2012 onwards, the memory chips are soldered on the logic board. This design significantly increases the reliability of the memory circuitry as it gets rid of the troublesome RAM slots. If you hear beeps from these MacBooks, you have a logic board problem. You need component-level repair service to fix the logic board. The cost varies from $300 to $600 depending on the Mac model.

3.7 Check for a faulty trackpad

The SMC is powered by an "always-on" power rail called PP3V42_G3H. The trackpad shares this power rail with the SMC. If the trackpad has a short circuit, especially after a water spill on the trackpad, the faulty trackpad could pull down the power rail and the SMC will not be functional. Therefore the SMC will not respond to the action of the power button.

Open the back panel of your Mac and remove the trackpad cable from the logic board. Then press the power button on the keyboard. If your Mac turns on, then you have a faulty trackpad. The trackpad is a less expensive MacBook component. You can buy a trackpad online for less than $100.

3.8 Check for a faulty keyboard

The MacBook keyboard also shares the "always-on" power rail with the SMC. If a faulty keyboard pulls down the power rail, the SMC won't work and won't respond to the power button signal.

Also, if the power button on the keyboard fails to send the signal to the SMC, your MacBook Pro or MacBook Air won't turn on. These types of faults are common after a liquid spill on the keyboard. Sometimes the keyboard stops functioning straight after a water spill, and sometimes the keyboard would stop working after a few months of spillage.

Remove the keyboard connector AND the battery from the logic board, then connect a MacBook charger to the charging port. Your Mac would automatically power on if the fault is in the keyboard. A MacBook with Intel i3, i5, i7 and i9 CPU will automatically power on if you remove the battery and connect a charger to it

3.9 Restore corrupted T2 security chip firmware

Starting in 2018, Apple integrated the SMC chip to a larger multifunctional chip called Apple T2 security chip in the new MacBooks. The T2 chip takes over the duty of SMC. If the T2 chip is not functional, it won't respond to the power button and your MacBook won't turn on.

When you update your Mac's macOS, for example from Mojave to Catalina, and something goes wrong in the middle the process, you could brick your Mac.

Apple time to time includes device firmware update (DFU) in the normal security update or version update. This DFU will update your Mac's FIRMWARE. When you install the macOS update that contains a DFU, you not only update the macOS software in your SSD drive, but also the firmware in the T2 chip. Therefore you don't have to buy a new Mac in order to run the new macOS smoothly or fully optimise the new features.  However, if the firmware update failed to complete the whole process for some reason, you could end up with T2 chip firmware corruption. In other words, you may have bricked your Mac.

To fix a bricked Mac, you need a working Mac and download the firmware from Apple's website. Then you force the bricked Mac into DFU mode so you can transfer the firmware to the bricked Mac via a USB cable shown as below:

1. Go to Apple's website to download the app Apple Configurator 2. You may need to update to the latest macOS to run the app. Open the app and make sure your Mac is connected to the internet.
2. Use your USB-C charger cable as a USB cable. Connect one end to any port of your working Mac.
3. Connect the other end of the USB-C cable to the MASTER port of your bricked Mac. The master USB-C port is the one on your left-hand side and closer to you.
4. Press the power button or touch ID button for 1 second. While holding the power button, press and hold the Control and Option keys on the left-hand side, the Shift key on the right-hand side until you see the big font text "DFU" showing on the working Mac. Usually, it will take about 10 seconds for the "DFU" sign to show up.
5. Release all the 4 keys at the same time. Now your bricked Mac is in DFU mode.
6. Go back to your working Mac, click to select the DFU device on the screen and select Action from the menu bar. On the pull-down menu bar select Advance and select Revive Device. Confirm the action.
7. Now the working Mac will download the correct firmware from Apple's server and install the firmware to your bricked Mac. This may take up to 5 minutes.
8. After finishing the installation, your Mac will automatically power on. If you can see the Apple logo, congratulations! You have successfully saved the bricked Mac.

3.10 Check for a faulty battery data cable

The 15 inch and 16 inch MacBook Pros manufactured between 2016 and 2020 behave very differently. Unlike the other MacBooks, these models of MacBooks will not power on normally without a working battery connected to it even if you connect a working charger to it.

In the new MacBooks with USB-C charging ports, the battery power terminals and data communication lines are no longer on the same connector. Instead, the power terminals ("+" and "-") are connected to the logic board and secured by a T5 screw to provide better contacts. The data lines are connected to the logic board via a flex cable.

This tiny flex cable is prone to failure. If the battery fails, or the battery flex cable fails to contact properly, your Mac won't turn on. But if you connect the USB-C charger to it, it will show a charging battery symbol on the screen for a few seconds then turn off again as shown below:

If you see this symbol, you most likely have a battery problem. Replacing the battery is very expensive if you get it done by Apple stores or Apple authorised service providers. They will replace the whole top case including your WORKING keyboard, trackpad, touch bar, speakers along with the faulty battery. Of course, you have to pay for all these components if your Mac is out of warranty. A third-party repairer may replace the faulty battery only at a low cost.

4. Choose repair services - Apple vs. third party

If all the above attempts failed to fix your MacBook, you may consider using a professional MacBook repair service.

There are two types of services. The first type is Apple Stores and Apple Authorised Service Providers (ASP). The second type is a third-party repairer. We will discuss the pros and cons of these services.

4.1 Apple Stores and ASPs

We suggest you make an appointment with the Genius Bar or ASP to get a free diagnosis and quote, no matter if you intend to use their service or not. These are the services you can get from them depending on whether or not your Mac is under warranty:

If your Mac is under warranty, you don't have to worry about anything except for your data. They will replace the faulty component for free. Apple will NOT take responsibility for your data or provide data transfer/recovery service. Therefore make sure the service will not affect your data. If the service could cause data loss and you haven't backed up your data on iCloud, you may need to back up the data to an external hard drive yourself or use a professional data recovery service.

If your Mac won't turn on due to a liquid spill, and the colour of the liquid indicators has changed from white to red as shown in the photo below, you void the standard warranty. All MacBook models have liquid indicators near the entrances where liquid can get in easily. The liquid damage indicators are usually under the keyboard, trackpad, and the edges of the logic board.

If you have purchased AppleCare+ that covers water damage, Apple will charge a $429 excess fee to get your Mac repaired.

If your Mac is out of warranty, you need to pay for replacing the faulty component. They provide high standard services and you don't have to worry about quality issues. But the services are expensive. They don't repair individual MacBook components. Instead, they replace multiple related components at a high cost. For example, if you have a swollen battery, you have to replace the top case, keyboard, trackpad, and touch bar all together even if they are still working beautifully.

If you purchased the Mac from a large department store, getting service from Apple directly can avoid unnecessary delay. You won't need any middle agent to deal with the repair.

If you have a faulty logic board, they may tell you the Mac is not repairable or quote a very high price for logic board replacement. This is the tactic to promote the new Mac sales. They will not tell you that there are some Mac repair specialists who can repair the logic board professionally at a fraction of their quote price.

4.2 Third-party services providers

The computer service industry is not a regulated industry. The level of third-party services varies from top professionals to newbies.

You can easily find a local computer repair store even if you live in a remote small town. They may be very good at fixing your Windows software problems. They may be very good at upgrading the hard drive in your Windows-based laptop or they may have done a good job replacing your broken iPhone screen. But the majority of these stores lack the skills, knowledge and equipment to handle the complexity of Mac computers. If your Mac has a simple problem such as faulty trackpad or battery, you may consider these service providers. If you have a logic board problem, avoid using these services.

There are some third-party service providers that offer services close to Apple's standard. They may charge much less than Apple or ASPs. So it is worth getting a second quote from these service providers addition to Apple's quote. Besides the prices, pay attention to the fault descriptions. Do they have the same diagnosis result? If not, talk to them for more details.

Customer reviews such as Google Reviews, Yelp Reviews can provide lots of information about the service providers. Do they have a high rating? How many reviews relate to Mac computers such as MacBook, iMac, Mac Mini? If the majority of the reviews are not for Macs, they may not have adequate experiences on Mac repairs. If the reviews have no details, only a few words like "excellent" "highly recommend", discount the reviews.

There are some Mac repair specialists who offer component (chip) level logic board repairs. Their skills and knowledge are well above the Genius Bar's technicians. Apple technicians may tell you that the logic board is not repairable. This is not true. The majority of faulty logic boards can be economically repaired with proper skills, knowledge and equipment.

These Mac repair specialists work on troubleshooting logic board components (or chips) such as transistors, resistors, capacitors, CPUs, GPUs and so on. They can identify the faulty chips among the many thousands on the board and then replace them without damaging the surrounding chips. This is the most economic way to get your Mac working again. The logic board repair services cost $200-$600 depending on the Mac model.

If you check the customer reviews of these Mac repair specialists, you will find the majority or even all the reviews are about Mac repairs. Lots of people would share the details of their repair experiences after they received outstanding services.

Unfortunately, there are only a handful of chip-level repair services available even if you live in a large city. So if you can't find any in your city, you may consider sending your Mac to another city or country to get it repaired. Again, check their customer reviews and talk to them before sending your Mac.

https://www.rossmanngroup.com/Currently, We only offer mail-in service within Australia. If you are in the United States or other countries, contact Rossman Repair Group in New York. They offer a worldwide mail-in service.

5. Professional MacBook repair in action

There are two levels of professional MacBook repairs: basic repairs and advanced repairs. The Genius Bar technicians, ASP technicians and most experienced third-party repairers offer basic repairs only. The Mac repair specialists offer both basic repairs and advanced repairs.

5.1 Basic Mac repairs

A MacBook consists of the following parts: a screen, keyboard, touchpad, battery, mechanical or SSD hard drive, DVD drive, Wifi card, logic board and Cables connecting other parts to the logic board. The objective is to identify the faulty part(s) and replace it.

This type of repair doesn't require advanced electronics knowledge, micro-soldering skills and understanding of MacBook logic board design. This is how they approach MacBook repairs:

1. Open the bottom panel and inspect any liquid or corrosion inside the Mac.
2. If there is no water damage, connect a dedicated power unit to the MacBook. Check for the electric current being drawn from the power supply.
3. Press the power button on the keyboard to see if there are any current changes. If there is no change, remove the keyboard cable, battery cable and any other cables from the logic board and perform a "forced" power-on to the logic board. If there is still no change of current, the logic board is faulty.
4. If the logic board can be powered on manually, re-connect cables one by one to determine which one is preventing the logic board from powering on.
5. Replace the faulty part(s) that prevent the Mac from turning on.
6. This part-replacing type of repair is entirely dependent on the availability of the spare parts. If there are no spare parts then there is no fix.
7. The logic board is the most expensive part of the Mac. If the logic board is faulty, the Mac will be considered as "not fixable" by this level of repairer. Apple may offer a logic board replacement at a high price.

5.2 Advanced Mac repairs

Logic board failures account for the majority of dead Macs. Repairing the failed logic board is the most cost-effective way to save your Mac. Only component level service providers can carry out this type of task:

1. Remove the logic board from the Mac case.
2. Inspect the logic board using a microscope. Look for any obvious burned, corroded chips.
3. Replace any faulty chips found. Micro-soldering skills are required to replace the small chips. Replacing a larger chip such as GPU or CPU needs a BGA rework station and the related skills.
4. Connect a dedicated power supply to the logic board. Based on the electric current being drawn from the power supply and other basic measurements, an experienced technician or engineer could lock-in the possible faulty circuit.
5. Work with Apple's schematics (electronic circuit design diagram), follow the control signals, measure the relevant resistors, capacitors, ICs and voltages with a multimeter, measure the electronic signals with an oscilloscope or logic analyzer to narrow down the fault area. And finally, pinpoint the faulty chips.
6. Replace the faulty chips. Repeat this process until all the faulty chips are found and replaced.
7. Assemble the logic board back to the case. Test Mac's functionality and reliability with ASD (Apple Service Diagnostic) and other third-party testing software. If the Mac failed to pass the test, pull out the logic board and start troubleshooting again.

Pinpoint the faulty chips among the many thousands on the logic board is a complex reasoning process. In one sense, it is like a meticulous forensic investigation. In order to perform the task effectively and economically, one needs specific electronic knowledge, detective reasoning skills, micro-soldering skills, experience, proper equipment and most importantly: a comprehensive understanding of the Apple Mac logic board designs – the electronic schematic diagrams.

Macbook Air Can Not Turn on

Source: https://www.it-tech.com.au/macbook-wont-turn-on/

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