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Old 01-20-2022, 05:25 AM   #1
reset1986
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Default macbook, 820-00165 turns on, magsafe light off and does not charge

hi to all, practically, this mainboard came to me off, there was no power supply to the 3 and 5 v TPS 51980a ic enable pin
after a floating reflow of the smc
the mac starts up without battery, but the magsafe light still off and does not enable me to recharge,

I find sys_onwire 0.5V

Flexible connector solders are good

advice?
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Old 01-20-2022, 06:40 AM   #2
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Default Re: macbook, 820-00165 turns on, magsafe light off and does not charge

Are you using an official power adapter from Apple ? (not a clone)

See attached.

Meter in DC volts scale (20V should be ok).

Attach your (official) power adapter.

Post the voltages for each requested location. Magsafe light needs 3v42 to operate so that is the first area for your investigation.
Attached Images
File Type: png D7005.png (90.4 KB, 19 views)
File Type: png PP3V42_G3H.png (145.4 KB, 19 views)
File Type: png DCIN.png (79.8 KB, 14 views)
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Old 01-20-2022, 09:30 AM   #3
reset1986
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Default Re: macbook, 820-00165 turns on, magsafe light off and does not charge

Quote:
Originally Posted by mon2 View Post
Are you using an official power adapter from Apple ? (not a clone)

See attached.

Meter in DC volts scale (20V should be ok).

Attach your (official) power adapter.

Post the voltages for each requested location. Magsafe light needs 3v42 to operate so that is the first area for your investigation.

I get the correct voltages in those points,
PP3V42_G3H 3.42V

PPVBAT_G3H_CHGR_REG 8. 5 L7130

SMC_BC_ACOK 3.3V

SMC_ONOFF_L 3.3v

SMC_RESET_L 3.3v

SYS_ONEWIRE missing 0.4v

the mac the fan runs, works fine without battery, magsafe light off

with battery it starts but shows me the low battery symbol, not charged and magsafe light always spent.

sys_onewire not shorted but not generated,
can I test the DC Board if it generates sys_onewire?

original power supply 14.85V 45W

Last edited by SMDFlea; 01-20-2022 at 11:27 AM.. Reason: english
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Old 01-21-2022, 07:18 PM   #4
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Default Re: macbook, 820-00165 turns on, magsafe light off and does not charge

I don't understand if the sys_onewire signal must be generated by the dc board or by the smc, I have all the smc signals except sys_onewire
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Old 01-21-2022, 08:25 PM   #5
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Default Re: macbook, 820-00165 turns on, magsafe light off and does not charge

It is the SMC that does the one wire communication.

Perhaps corrosion under the SMC? You can flux and reflow the SMC if you are comfortable. Use tweezers to slightly nudge the corners to make the ic dance. This process then aligns the underside balls onto the pcb pads.

See here on more details:

https://www.it-tech.com.au/mac-q-a/macbook-smc-circuit/
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Old 01-21-2022, 09:16 PM   #6
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Default Re: macbook, 820-00165 turns on, magsafe light off and does not charge

Quote:
Originally Posted by mon2 View Post
It is the SMC that does the one wire communication.

Perhaps corrosion under the SMC? You can flux and reflow the SMC if you are comfortable. Use tweezers to slightly nudge the corners to make the ic dance. This process then aligns the underside balls onto the pcb pads.

See here on more details:

https://www.it-tech.com.au/mac-q-a/macbook-smc-circuit/
I reballed all smc, clean unsoldered, built with 0.30 spheres, resoldered,
same situation, I have the sys_onewire 0.5v
is there any signal I need to check that enables the sys_onewire output from the smc?

i wanted to ask if without ribbon cable between dc board and motherboard the sys onewire value is 3.3v or it is not generated,
thank you

Last edited by reset1986; 01-21-2022 at 09:28 PM..
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Old 01-22-2022, 06:36 AM   #7
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Default Re: macbook, 820-00165 turns on, magsafe light off and does not charge

See attached. Post the voltages on U6900.
Attached Images
File Type: png U6900.png (47.3 KB, 16 views)
Attached Files
File Type: pdf MAX9940.pdf (234.0 KB, 6 views)
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Old 01-22-2022, 10:42 AM   #8
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Default Re: macbook, 820-00165 turns on, magsafe light off and does not charge

Quote:
Originally Posted by mon2 View Post
See attached. Post the voltages on U6900.
i have a main 820-00165, sys_onewire does not go from u6900, goes direct from smc U5000 to J9500,
c is continuity of signal between the two points, do you have any other advice? thanks
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Old 01-22-2022, 10:54 AM   #9
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Default Re: macbook, 820-00165 turns on, magsafe light off and does not charge

Thanks for the clarification.

@Piernov has an excellent guide on faults that may surface on the A1466 logic board. He nailed it for a repair a few months ago and was linked to the SMC device and parts he mentioned in the article. I will see if I can find that post and link it here.

In the meantime, have you tested with another DC board ? This could be a critical component to your case. You may be able to test with another donor board.

How are the contacts of your magsafe connector ? Have seen some nasty ones come into our shop and had to use alcohol to clean up the contacts. Customers sometimes, without their knowledge, will buy counterfeit power adapter that arc the h*ll out of the mating contacts. You can buy replacement magsafe connectors but found it to be a real waste of time - just much easier to replace the DC power board which will contain some form of one-wire protection. If that part is damaged then this could be halting the communication between the adapter & the SMC.

Try this, meter in resistance mode (2K) - remove all power to the logic board. Remove the add-on DC power board with the magsafe connector.

Red meter probe on the SYS_ONEWIRE (pin 19) on J9500.

Black meter probe to ground.

What is the reading ?

Then, add the DC paddle board - still do not apply any power to the logic board.

Measure again.

What is the resistance with the DC paddle board attached ? Same or different ?

Updates:

https://www.repair.wiki/w/A1466_2013...9D_MacBook_Air

https://www.repair.wiki/w/A1466_2015...9D_MacBook_Air
Attached Images
File Type: png J9500.png (141.1 KB, 4 views)

Last edited by mon2; 01-22-2022 at 10:57 AM..
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Old 01-22-2022, 01:43 PM   #10
reset1986
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Default Re: macbook, 820-00165 turns on, magsafe light off and does not charge

Quote:
Originally Posted by mon2 View Post
Thanks for the clarification.

@Piernov has an excellent guide on faults that may surface on the A1466 logic board. He nailed it for a repair a few months ago and was linked to the SMC device and parts he mentioned in the article. I will see if I can find that post and link it here.

In the meantime, have you tested with another DC board ? This could be a critical component to your case. You may be able to test with another donor board.

How are the contacts of your magsafe connector ? Have seen some nasty ones come into our shop and had to use alcohol to clean up the contacts. Customers sometimes, without their knowledge, will buy counterfeit power adapter that arc the h*ll out of the mating contacts. You can buy replacement magsafe connectors but found it to be a real waste of time - just much easier to replace the DC power board which will contain some form of one-wire protection. If that part is damaged then this could be halting the communication between the adapter & the SMC.

Try this, meter in resistance mode (2K) - remove all power to the logic board. Remove the add-on DC power board with the magsafe connector.

Red meter probe on the SYS_ONEWIRE (pin 19) on J9500.

Black meter probe to ground.

What is the reading ?

Then, add the DC paddle board - still do not apply any power to the logic board.

Measure again.

What is the resistance with the DC paddle board attached ? Same or different ?

Updates:

https://www.repair.wiki/w/A1466_2013...9D_MacBook_Air

https://www.repair.wiki/w/A1466_2015...9D_MacBook_Air
Ok, without dc board, i don't measure resistance value in sys_onewire, in diode mode 348

if I connect the dc board I measure 2.3Kohm
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Old 01-23-2022, 04:02 AM   #11
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Default Re: macbook, 820-00165 turns on, magsafe light off and does not charge

The sys_onewire circuit is identical to that of the older MAC's, just that the AND gate and protection IC's are on the DC IN board. For reference, they are just to the right of the audio connector on the DC in board. For them to work, you need to confirm you have SMC_BC_ACOK and PP3V42_G3H on the board. I assume you have checked a known good DC IN board and LIO flex cable, so check the presence of these signals at J9500 and on the DC IN board AND gate and protection IC. You can also put a CRO on the sys_onewire testpoint too to see what activity you have.
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Old 01-23-2022, 09:33 PM   #12
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Default Re: macbook, 820-00165 turns on, magsafe light off and does not charge

Quote:
Originally Posted by reset1986 View Post
Ok, without dc board, i don't measure resistance value in sys_onewire, in diode mode 348

if I connect the dc board I measure 2.3Kohm
Quote:
Originally Posted by reformatt View Post
The sys_onewire circuit is identical to that of the older MAC's, just that the AND gate and protection IC's are on the DC IN board. For reference, they are just to the right of the audio connector on the DC in board. For them to work, you need to confirm you have SMC_BC_ACOK and PP3V42_G3H on the board. I assume you have checked a known good DC IN board and LIO flex cable, so check the presence of these signals at J9500 and on the DC IN board AND gate and protection IC. You can also put a CRO on the sys_onewire testpoint too to see what activity you have.
Quote:
Originally Posted by mon2 View Post
See attached. Post the voltages on U6900.
thanks for the advice, U6901 pulled down smc_bc_acok vcc on U6900, replaced u6901 all back working, battery charged magsafe led on
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Old 01-24-2022, 04:31 AM   #13
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Default Re: macbook, 820-00165 turns on, magsafe light off and does not charge

You mean on the DC IN board? Good grief! Exchanging that board should have been the first thing you tried. And you reballed a SMC? I have no words.
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Old 01-24-2022, 05:26 AM   #14
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Default Re: macbook, 820-00165 turns on, magsafe light off and does not charge

Quote:
Originally Posted by reformatt View Post
You mean on the DC IN board? Good grief! Exchanging that board should have been the first thing you tried. And you reballed a SMC? I have no words.
the mac initially did not turn on due to smc not enabling the TPS 51980a ic, reballato smc started working again,
then later I found that sys_onewire was corrupted from the DC card
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