Macbook Air A2179 Motherboard Component Identifying

[dangnabbit]

Hi All,
I have a MacBook Air 2020 which has a problem with the motherboard. I lent my laptop to my friend for a week and he somehow destroy it. When I opened the laptop I found a capacitor/ resistance like the piece. Can you help me to Identify this part because there is no board view only partial boardview available and I could not determine it.

It is in between C7665 and C7685 approximately.

The laptop is not turning on though. But, I would like to fix that problem first. You can find pictures at the attachment.


Thanks in advance.

[mon2]

Re: Macbook Air A2179 Motherboard Component Identifying

Hi. See attached.

This is C7661 = 2.2uF non-polarized ceramic 0402 cap @ 25V.

This part missing will not impact the operation of the logic board.

If you are still interested to replace this missing part, send me a PM and can send it to you from Arrow - wish to test out the international free shipping with our company account. The part is very inexpensive so can just send it to you and you should receive it sometime next week. If the shipping is indeed free then we may consider to start a small biz to sell repair parts off the Arrow portal.

https://www.arrow.com/en/products/gr...-manufacturing

[dangnabbit]

Re: Macbook Air A2179 Motherboard Component Identifying

Hi mon2,

Wow, you are amazing! I guess you have the .brd version of the schematic. You are stunning! Do you have any suggestions for me for improving myself about reading schematics?

I am definitely still interested in it! I am sending you a PM!


Cheers!
Eva.

[mon2]

Re: Macbook Air A2179 Motherboard Component Identifying

Hi. Will reply to your PM in a bit.

1) For reviewing the schematic / boardview files, always look for an etched part # on the logic board. It should be of the format

820-xxxx

to identify the logic board.

2) Based on your posted location of the missing part, found in my database that it appear that you have 820-01958. Is this correct ?

Moving on - just sent you a reply to the PM.

Before heading over to my Netflix couch to watch more of Fauda...

3) review the LOGIWIKI (@Piernov wrote most the good stuff) on how and when the 20V rail is sourced. I could chat all night and bore you to death about the USB Power delivery but know that you should start with the basics.

https://www.logi.wiki/index.php/CD3215_Bootup_Sequence

Is the power adapter known to be good - really should be the Apple original. Does it still work ?

Next, with your meter in DC volts mode, check F7000 fuse and report the voltage on that fuse. Check both sides of the fuse (in case it is blown).

The summary here is that your external USB Power delivery capable power supply starts @ 5V and then does a hand shake of data packets with the logic board. If all goes well, the adapter dumps out a list of power contracts (volts & amps pairs) that the logic board reviews and selects the best one. For Apple it is 20V @ 5A usually but may be less for the smaller units.

If there is damage to the USB C connector(s) and/or the controller ICs linked to them - then 20V will NOT be selected and could be the issue on hand.

Do you see any liquid damage on the logic board ? Often there is a red color dot that triggers on liquid contact (white by default but red if liquid is seen).

Hope you have some tools to service this logic board but be prepared to study the schematics and the very very tiny parts onboard.

Update # 2 - see attached.

Look for a white surface mount part = F7000 (main fuse).

a) power down. meter in ohms mode (200 ohms). Check the resistance across F7000. Is it still ok with ~0 ohms ? If open, then you will not have a resistance reading = meaning the fuse is not allowing for the power to pass through.

b) if the fuse is ok -> meter in DC volts mode. carefully power on your Apple power adapter. Check the voltage to ground on F7000 (both sides of this part). What is the voltage reading ?

[piernov]

Re: Macbook Air A2179 Motherboard Component Identifying

That area of the board has clearly been heavily liquid damaged. Replacing one cap won't be enough to fix it.

[dangnabbit]

Re: Macbook Air A2179 Motherboard Component Identifying

2) Yes, it is! Oh wow, I am super envious of your knowledge!
3) Yes, it is original and working well. But, it is not powering it up.

Today I've ordered tools for myself and I want to learn more about PC repair as a hobby.

My voltmeter/ amp meter is arriving tomorrow. Do you think you would have some time if I send PM to you for asking stupid questions? During my bachelor education we only worked on old bulky electronic parts and I dunno where should I put + and - parts of the volt/amp meter on the components.

You are amazing! Thank you so much again! I'll write you a PM.

Note: I don't think there is a liquid damage on the board.

[dangnabbit]

Re: Macbook Air A2179 Motherboard Component Identifying

Dear piernov,

I appreciate your reply. The stains you are seeing must be excess electronic board corrosion remover liquid. It left some traces on the board. But I'd like to test components more if you have suggestions. I hope you would support me in my learning process as a woman. When I consult to my some friends they are making fun of me instead of supporting me... How can I use the volt/amp meter for the components? I was confused a bit because I got used to working on old and bulky versions of these.

Thanks for your precious message already!

[piernov]

Re: Macbook Air A2179 Motherboard Component Identifying

https://repair.wiki/w/Visual_inspection

[mon2]

Re: Macbook Air A2179 Motherboard Component Identifying

hi.

1) Recommend to source a USB C meter which are quite inexpensive on Aliexpress. You may have a local reseller of these tools as well.

For example,

https://www.aliexpress.com/item/4000...86887738%22%7D

We have something like this in the lab.

2) Which multimeter do you have on order. It will be a good start to monitor some of the points of the logic board. The USB C meter will show your quickly on the power delivery between the external adapter and this logic board.

3) To do the fine point soldering, a good toolset is recommended. We recently brought in the Sugon T26 which is quite nice and heats up in 2 seconds and then shuts off automatically when docked back into the cradle. The small complaint is that our original tips are almost worn out but took about 6+ months of constant abuse to get here. Have some clones on order. The original tips are from JBC but can be expensive.

https://www.unionrepair.com/sugon-t2...ering-tip.html

A good hot air station is also recommended along with a tweezer set + flux (Amtech or a good clone of it).

We purchased the hot air station from BEST (Model 863; Shenzhen, CN) whom we have met numerous times in China at past trade fairs. Their staff reported they can help us repair the unit if required and can sell us spare parts. That is the confidence we needed to move forward with that purchase.

Very pleased with the unit so far and have had it for about 1.5 years. The high setting of 550C can support the heavy ground planes on the PCB that appear to be common to Apple logic boards. Adjustable air settings so we can reflow small parts without blowing others off.

I would encourage you to at least continue this investigation. There is a very high demand for good techs to repair such electronics. The venture can get costly on the tools but take it a step at a time so you can justify the growth of your tools for your labwork.

For your logic board - did any of the liquid indicator dots get triggered ? They will turn RED (white is normal). Did your friend mention how this unit stopped working ? Based on the loose part, was the laptop dropped ?

[dangnabbit]

Re: Macbook Air A2179 Motherboard Component Identifying

My friend is missing. He is not answering my calls anymore, lol. The sticker is white, but due to poor cleaning by me looks messy. Now I am doing the multimeter part. I have read 0.02 amper on the fuse. BTW which voltage do I have to choose? You can find my multimeter's image in the attachment. Thanks for your precious help!

[mon2]

Re: Macbook Air A2179 Motherboard Component Identifying

See attached.

1) Start with the meter in the DC volts scale (see attached) @ 200V. Of course we do not anticipate such a high voltage on the board but need to confirm that 20V reaches the start of the logic board. If the POWER DELIVERY contracts negotiate correctly with the external adapter, the logic board will then select the "20V" contract to start the powering of this logic board.

2) The resistance mode can be used once you have the adapter removed. You MUST also remove the battery for these tests of the resistance on each coil to ground. Once the power has been removed, meter in 200 ohms scale.

Red meter lead on any (grey) coil on the logic board.

Black meter lead on a ground on the logic board. Can be the EMI metal shields that are onboard.

You are checking for ultra low resistance that may indicate a shorted capacitor or a shorted part.

Start with the voltage reading on F3000 & F3001 (each should be likely white in color) which will allow us all to know where you stand to start with on the external power adapter.

What voltage do you see with the adapter attached on these fuses ?

Next, review the fuse @ F7000 and post the voltage reading there.

Inductors are the GREY SMD (surface mount devices) with the inkjet markings like 2R2 = 2.2uH, etc. The reason to inspect these are because such large devices are linked to local switching power supply rails. Each inductor = a different power rail. If you read some kooky low resistance (< 10 ohms), then that area needs further investigation.

[piernov]

Re: Macbook Air A2179 Motherboard Component Identifying

Again, even if the picture is of very low quality, this area is clearly liquid damaged.

[dangnabbit]

Re: Macbook Air A2179 Motherboard Component Identifying

I cleaned up with alcohol today but it looks same.... Do you have any tips to cleaning up the board? I've cleaned with rubbing alcohol but there are some more corrosions I guess... Thanks!

[dangnabbit]

Re: Macbook Air A2179 Motherboard Component Identifying

Hi mon2,

OK, I did it this time I guess. You can find the picture of the fuses at the attachment. Readings are for amp. 1 for all, for volt. F7000: 0.03; F3000 & F3001: 05.1. I am so appreciated! I hope these readings are OK.

[FrozenHaxor]

Re: Macbook Air A2179 Motherboard Component Identifying

I cleaned up with alcohol today but it looks same.... Do you have any tips to cleaning up the board? I've cleaned with rubbing alcohol but there are some more corrosions I guess... Thanks!

Windex and toothbrush if you don't have an ultrasonic cleaner big enough. Be gentle, you can rip stuff out. Been using that method for years until I could afford proper equipment. Rinse the board with deionized water afterwards and blow dry with compressed air if you have access to that, or soak up most of the moisture with a paper towel by pressing it against the board carefully, then rinse the board with isopropyl alcohol. It will bond to remaining water rapidly and assist in through drying. Then I suggest baking the board in 60*C for 30 minutes. It will look like new and there will be no corrosion left. For stubborn stuff around ICs use good flux and reflow with hot air.

Isopropyl alcohol is much less polar than water, therefore it's not nearly as good at dissolving organic compounds and salts that the corrosion presents. That's why I recommend windex or a similar product of choice as they contain additional beneficial surfacants that will aid in cleaning.

[mon2]

Re: Macbook Air A2179 Motherboard Component Identifying

1) With the adapter connected, post the voltage on C7056 (+). Meter in DC volts (20V is ok); black meter lead on the negative side of this capacitor.

Red meter lead on the + side of this capacitor.

This step is checking for the voltage of PPBUS_G3H.

2) With the adapter connected, check and post the voltage on BOTH sides of F7000. Or are you reading this low voltage on both sides of this fuse ?

Pin #1 of F7000 is important to know if the local switching power supply is working. If Pin #2 of F7000 is zero then it is possible that the fuse is blown.

3) With the fuses @ F3000 & F3001 @ 5v1, we know that the power rail PPDCIN_G3H = 5v1. This rail is too low to power the logic board.

Respectively, require this rail to be @ 20v.

There are 2 USB connectors on this logic board. Each USB connector is controlled by a local CD3217 (ACE controller by Texas Instruments).

Both of these USB controllers must be working to allow for the 20V to be selected.

See the article here from @Piernov which is related:

https://www.logi.wiki/index.php/T2_a...er_on_Sequence

4) Also inspect the diodes from your posted pics to confirm they are not damaged. They look discolored - could this be corrosion or just not a good picture ?