MacBook Air Early 2015 13" No Power

[jasonr2000]

hi guys I have the above MacBook Air

ive got the schematic for it and the boardview file.

but I can't for the life of me figure out what's going on.

its as if its dead the MagSafe light turns on when connected and goes to green to say the battery is charged.

but there is no signs of life other than the fact that if I press the power button when I have a usb dongle connected it will spring to the life (the usb stick I mean)

but nothing else no fan spin no backlight no chime

nothing.

ive tried an SMC reset which seems to work.

but still no power on.

ive removed the bottom cover and can see no sign of water damage or anything.

it just was on then shut down and never came back after.

ive tried a new battery with the same results.


as I have the board files ive checked the board for shorts and find loads around the circled area.

but if I check for voltages im getting 8.5v on all the caps marked NEHAV7


thanks for any help.

picture attached

[mon2]

Re: MacBook Air Early 2015 13" No Power

Are you able to see the caps key toggle on your keyboard ?

If yes, then your OS is booting. Do not see a SSD docked in your posted pic but you can try this with a good OS onboard.

If you attach a display -> do you see any graphics ? Test with a flashlight / torch along the front face and also the backside of this top side display assembly (from the back of the Apple logo). Back then believe the logo was not solid but try this from all angles.

Perhaps only your backlight voltage is gone. This may be due to other factors including the lid switch which is in your trackpad.

ive tried an SMC reset which seems to work.

How are you confirming this is working ? Do you hear a chime ?

No liquid damage from wild parties ?

[jasonr2000]

Re: MacBook Air Early 2015 13" No Power

hi thanks for the reply

I have tried as you said but nothing im getting PP3 G3H voltage and im getting PP3V3_S5

im getting no voltage on Q7321 but im getting voltage on Q7320

and im getting the same on voltage on Q7310 and nothing on Q7311

they are both showing 8'6v

could this mean the CPU is dead ???

[mon2]

Re: MacBook Air Early 2015 13" No Power

What is the 820-xxxx # on your logic board so that we may reference the same schematic & boardview files ?

Need full details on how you are measuring and what you are measuring.

What is the voltage of PPVCC_S0_CPU rail ?

Next, remove all power -> meter in lowest resistance scale -> check the resistance to ground of PPVCC_S0_CPU.

One meter lead to PPVCC_S0_CPU.

Other meter lead to ground. What is the measurement in ohms ?

[jasonr2000]

Re: MacBook Air Early 2015 13" No Power

Hi board number is 820-00165-A

And where do I find PPVC_S0_CPU ?

Thanks

[mon2]

Re: MacBook Air Early 2015 13" No Power

Download the schematic and boardview file from here:

https://www.badcaps.net/forum/showpo...34&postcount=2

Search for the above 'PPVC_S0_CPU' netname and the PDF viewer will offer a match for each hit.

Then look for the same component inside the boardview file to locate where to probe. Suggestion is to use a large component like a coil.

You can probe @ L7310 (pin 2) - red meter probe here; black meter probe to ground.

Check the voltage on this coil. See attached.

[dellxps15]

Re: MacBook Air Early 2015 13" No Power

take mainboard out. connect only io board , fan and magsafe connector.

connect psu, light should turn green to orange and fan should spin..... meanwhile after psu is connected check if cpu voltage comes at around 1,75v.

if cpu volt comes for few seconds and fan stop spinning, i would replace u1950.

[jasonr2000]

Re: MacBook Air Early 2015 13" No Power

What is the 820-xxxx # on your logic board so that we may reference the same schematic & boardview files ?

Need full details on how you are measuring and what you are measuring.

What is the voltage of PPVCC_S0_CPU rail ?

Next, remove all power -> meter in lowest resistance scale -> check the resistance to ground of PPVCC_S0_CPU.

One meter lead to PPVCC_S0_CPU.

Other meter lead to ground. What is the measurement in ohms ?

after checking resistance I can see 63.3 ohms is that normal ???

by probing on ground and C1089 and R7310

thanks for the help so far.

[jasonr2000]

Re: MacBook Air Early 2015 13" No Power

Download the schematic and boardview file from here:

https://www.badcaps.net/forum/showpo...34&postcount=2

Search for the above 'PPVC_S0_CPU' netname and the PDF viewer will offer a match for each hit.

Then look for the same component inside the boardview file to locate where to probe. Suggestion is to use a large component like a coil.

You can probe @ L7310 (pin 2) - red meter probe here; black meter probe to ground.

Check the voltage on this coil. See attached.

hi again

ive checked for voltage on L7310 and im getting no voltage at all..

if I check on the following cap C7372 I get 8.6v

[mon2]

Re: MacBook Air Early 2015 13" No Power

Any power rail that is super low in voltage like ~1v0 or similar is often a low resistance.

Your reading of ~63 ohms is not considered to be a low resistance for the CPU power rail.

We measured a macbook logic board in the past few weeks where the CPU rail was @ 1 ohms and thought to be dead for sure. The unit worked fine. The client had other faults like a bad keyboard and the keyboard was the rivet style so he just scrapped the unit rather than pay for the labor to fix it.

Review the comments by @dellxps15. Place your meter in voltage mode.

What voltage do you read @ PPVCC_S0_CPU ? You can measure with the red meter probe at the same coil as before; black meter probe to ground.

What is the voltage reading ?

Good to also measure the voltage to ground on other similar coils on the logic board. Report any zero or low voltage readings. Each coil is linked to a power rail.

[jasonr2000]

Re: MacBook Air Early 2015 13" No Power

hi thanks again for the reply on the coils near the CPU I get no voltage at all on the one near the SSD slot I get 3.3v on the one near the fuse I get 8.6v


if im correct with my voltmeter the ohms setting is on the bottom ???

[jasonr2000]

Re: MacBook Air Early 2015 13" No Power

also checking for power on all the coils I will label them as follows

L7320 0V
L7310 0V
L7630 0V
L7430 0V
L7560 3.3V
L7520 5.0V
L7130 8.6V
L3095 0V
L7701 0V

hope that helps

[mon2]

Re: MacBook Air Early 2015 13" No Power

if im correct with my voltmeter the ohms setting is on the bottom ???

Correct. You are on the DC volts scale and the 20 setting denotes the max voltage that you can measure on this setting. If you reach 21v (as an example), the meter should report 'OL' or '1' = over limit status.

Then you should select a higher meter scale on the DC volts till you have a proper reading.

Yes, resistance scales are more counter-clockwise to this DC volts setting and with the ohms symbol.

Although you have a LED on for the magsafe head, confirm the voltage readings on:

pin # 1, pin # 2 and pin # 3 of D7005.

Red meter probe on pin # 1; black meter probe to ground. What is the voltage ?

Repeat with red probe on pin # 2 & ground and finally pin # 3 and ground. Post each measurement.

[jasonr2000]

Re: MacBook Air Early 2015 13" No Power

should I set it at 200 ohms ?

[mon2]

Re: MacBook Air Early 2015 13" No Power

No - we are not reading resistance at this time. Later, perhaps. Now you need to leave the meter on the 20V DC scale like your picture you posted.

[jasonr2000]

Re: MacBook Air Early 2015 13" No Power

ok great

so these are the voltages im getting on the coils

L7320 0V
L7310 0V
L7630 0V
L7430 0V
L7560 3.3V
L7520 5.0V
L7130 8.6V
L3095 0V
L7701 0V

hope that helps

[dellxps15]

Re: MacBook Air Early 2015 13" No Power

if u have, disconnect the flat cable from io board and try again

[mon2]

Re: MacBook Air Early 2015 13" No Power

Review and post the voltages on the D7005 dual diode - see above on the details. This is for a critical voltage leg which has to be 3v42 (suspecting it is ok since you have a LED on for your magsafe). Small concern is that there are lots of fake chargers on the market and can cause the LEDs to turn on regardless of this voltage rail.

[jasonr2000]

Re: MacBook Air Early 2015 13" No Power

if u have, disconnect the flat cable from io board and try again

connected or not no change to voltages

and no fan spin.

[jasonr2000]

Re: MacBook Air Early 2015 13" No Power

Review and post the voltages on the D7005 dual diode - see above on the details. This is for a critical voltage leg which has to be 3v42 (suspecting it is ok since you have a LED on for your magsafe). Small concern is that there are lots of fake chargers on the market and can cause the LEDs to turn on regardless of this voltage rail.

ok on pin 1 I get 8.5V
and on pin 2 I get 14.9V
and on pin 3 I get 14.7V