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**mon2** · 11-22-2021, 05:47 AM

Re: Macbook Pro a1708 820-00840 no power

What is the voltage of PP3V3_G3H ?

**nikey22** · 11-22-2021, 07:54 PM

Re: Macbook Pro a1708 820-00840 no power

agree with @mon2

Before we blame the CD3215, we have to make absolutely sure we have power to the CD3215s.

PP3V3_G3H is generated by U6990, it can be measured at R6999. This is a mandatory rail before power up the 15s.

However, in order for U6990 to generate 3.3V, it needs an "enable" signal from the ISL9239 (U7000).
This enable signal can be measured at PM_EN_P3V3_G3H_R located on R6991, basically pin #10 of the U6990.

However, in order for U6990 to do any of this, its needs some power from either the charger or the battery.
This comes from PPVIN_G3H_P3V3G3H, and it can be measured at diode D6905, basically pin #2 of the U6990.
You did this already in your previous post, and received a reading close to 5V. Please confirm.
If the voltage here is closer to 1, we have a short somewhere along those capacitors: C6990, C6991 or possibly the diode itself is bad. But I believe you got ~4.8V.

So we need to attack this on 3 fronts:

power in side: PPVIN_G3H_P3V3G3H
enable circuitry: PM_EN_P3V3_G3H_R
power out side: PP3V3_G3H

Note: if one CD3215 doesn't work, the other won't either.
Note: Always choose the CD3215C00 for the 20V negotiation. Are they both this revision?
Note: schematic is missing capacitor C7078 that makes up part of the power in side.

Keep us posted.

**tahakxrd** · 11-23-2021, 01:25 PM

Re: Macbook Pro a1708 820-00840 no power

Originally posted by nikey22 View Post

agree with @mon2

Before we blame the CD3215, we have to make absolutely sure we have power to the CD3215s.

PP3V3_G3H is generated by U6990, it can be measured at R6999. This is a mandatory rail before power up the 15s.

However, in order for U6990 to generate 3.3V, it needs an "enable" signal from the ISL9239 (U7000).
This enable signal can be measured at PM_EN_P3V3_G3H_R located on R6991, basically pin #10 of the U6990.

However, in order for U6990 to do any of this, its needs some power from either the charger or the battery.
This comes from PPVIN_G3H_P3V3G3H, and it can be measured at diode D6905, basically pin #2 of the U6990.
You did this already in your previous post, and received a reading close to 5V. Please confirm.
If the voltage here is closer to 1, we have a short somewhere along those capacitors: C6990, C6991 or possibly the diode itself is bad. But I believe you got ~4.8V.

So we need to attack this on 3 fronts:

power in side: PPVIN_G3H_P3V3G3H
enable circuitry: PM_EN_P3V3_G3H_R
power out side: PP3V3_G3H

Note: if one CD3215 doesn't work, the other won't either.
Note: Always choose the CD3215C00 for the 20V negotiation. Are they both this revision?
Note: schematic is missing capacitor C7078 that makes up part of the power in side.

Keep us posted.

Thank you so much for the info youve provided me,@mon2 and @nikey22 both of you, on the port that i stated isnt working, i am getting 0v on all three PPVIN_G3H_P3V3G3H,PM_EN_P3V3_G3H_R
and PP3V3_G3H.
On the port that i am getting v5 using amp meter its got 5.10v on PPVIN_G3H_P3V3G3H,PM_EN_P3V3_G3H_R but 0v on PP3V3_G3H. please note i have no chip currently on u3200 if that makes any difference.

what should i test next if you please assist me id be extremely greatful.

**tahakxrd** · 11-23-2021, 01:34 PM

Re: Macbook Pro a1708 820-00840 no power

Originally posted by nikey22 View Post

agree with @mon2

Before we blame the CD3215, we have to make absolutely sure we have power to the CD3215s.

PP3V3_G3H is generated by U6990, it can be measured at R6999. This is a mandatory rail before power up the 15s.

However, in order for U6990 to generate 3.3V, it needs an "enable" signal from the ISL9239 (U7000).
This enable signal can be measured at PM_EN_P3V3_G3H_R located on R6991, basically pin #10 of the U6990.

However, in order for U6990 to do any of this, its needs some power from either the charger or the battery.
This comes from PPVIN_G3H_P3V3G3H, and it can be measured at diode D6905, basically pin #2 of the U6990.
You did this already in your previous post, and received a reading close to 5V. Please confirm.
If the voltage here is closer to 1, we have a short somewhere along those capacitors: C6990, C6991 or possibly the diode itself is bad. But I believe you got ~4.8V.

So we need to attack this on 3 fronts:

power in side: PPVIN_G3H_P3V3G3H
enable circuitry: PM_EN_P3V3_G3H_R
power out side: PP3V3_G3H

Note: if one CD3215 doesn't work, the other won't either.
Note: Always choose the CD3215C00 for the 20V negotiation. Are they both this revision?
Note: schematic is missing capacitor C7078 that makes up part of the power in side.

Keep us posted.

I can confirm when testing U6990 on pin 7 i am AGND_P3V3G3H which now reading the name of the pin its ground, and r6991 when testing in continuity mode it is beeping.

**mon2** · 11-23-2021, 01:40 PM

Re: Macbook Pro a1708 820-00840 no power

1) You do require both CD3215 devices to be present and they must be functional to kick on the 20V rail.

PPVIN_G3H_P3V3G3H @ 5v1 is ok as it matches the USB DCIN (PPDCIN_G3H_CHGR).

2) PP3V3_G3H is a critical rail and this rail must be on @ 3v42 to start the logic board operation.

If you are missing this rail, start with:

a) voltage on PP3V3_G3H_VR ?

b) voltage on PM_EN_P3V3_G3H_R ?

If PP3V3_G3H is still NOT @ 3v42 (required), then remove all power.

Meter in resistance mode (2k is ok).

Check and post the resistance to ground of PP3V3_G3H to ground.

Red meter probe on PP3V3_G3H / black meter probe to ground.

Resistance value ? You may have an excessive load on PP3V3_G3H causing this fault.

**tahakxrd** · 11-23-2021, 01:56 PM

Re: Macbook Pro a1708 820-00840 no power

Originally posted by mon2 View Post

1) You do require both CD3215 devices to be present and they must be functional to kick on the 20V rail.

PPVIN_G3H_P3V3G3H @ 5v1 is ok as it matches the USB DCIN (PPDCIN_G3H_CHGR).

2) PP3V3_G3H is a critical rail and this rail must be on @ 3v42 to start the logic board operation.

If you are missing this rail, start with:

a) voltage on PP3V3_G3H_VR ?

b) voltage on PM_EN_P3V3_G3H_R ?

If PP3V3_G3H is still NOT @ 3v42 (required), then remove all power.

Meter in resistance mode (2k is ok).

Check and post the resistance to ground of PP3V3_G3H to ground.

Red meter probe on PP3V3_G3H / black meter probe to ground.

Resistance value ? You may have an excessive load on PP3V3_G3H causing this fault.

i am getting 0v on both PP3V3_G3H_VR and PM_EN_P3V3_G3H_R and for PP3V3_G3H i am getting open loop (.0L)

**mon2** · 11-23-2021, 02:08 PM

Re: Macbook Pro a1708 820-00840 no power

PM_EN_P3V3_G3H is an output signal that is created by U7000. This signal needs to be 4-5V to enable the U6990 buck regulator.

reference:
https://boards.rossmanngroup.com/thr...3v3_g3h.55838/

Given that this enable signal is low, U7000 may be defective and needs to be replaced. Perhaps others have additional advice but believe that the ISL9239 needs to be replaced. It is a tiny WLCSP package that takes some care to replace. Lots of flux and wait till it starts to dance before plucking off the board. We do not want to lose any of the SMD pads.

Do watch the video from Louis and others on this topic. If anything else comes to mind, will post back.

The resistance on the rail (PP3V3_G3H) that U6990 creates is OK if OL.

Comment: As a suggestion, you could flux up U7000 and apply hot air to allow for remelting / reseating of the pads. Worth a try short of replacing the component. We usually wait till the device dances a bit but be careful to not send it flying off the board. Personally, my eyes will never find the part again...

**nikey22** · 11-23-2021, 06:14 PM

Re: Macbook Pro a1708 820-00840 no power

Originally posted by mon2 View Post

2) PP3V3_G3H is a critical rail and this rail must be on @ 3v42 to start the logic board operation.

Greetings @mon2

I'm curious, did you mean 3.3V? or indeed 3.42V. There are no PP3V42 rails on the 2018-2020 class computers that uses USB-C as far as I know;
PP3V42_G3H is of course the 1st and mandatory rail on the boards that have magsafe 2/green-light on charger (eg ~ A1466).

**mon2** · 11-23-2021, 08:45 PM

Re: Macbook Pro a1708 820-00840 no power

Yes, oops. Thanks. My bad..too many schematics in my fading mind.

On this rail, one can argue whether it is the first rail. This rail cannot turn on unless the enable (active high) is present. The active high enable is the signal output from typically U7000 (ISL9239 / ISL9240). So the enable status pin has to be present first.

**mon2** · 12-06-2021, 12:01 PM

Re: Macbook Pro a1708 820-00840 no power

Updating this thread.

PP3V3_G3H is indeed @ 3v42 on the A1708 (820-00840). Have this logic board in the shop now.

The logic board boots fine on battery but unable to charge the battery. PPBUS_G3H remains @ 0V with the adapter only. Adapter negotiates with 20V @ ~34-36mA.

The battery (~11v5) allows for the fan spin & display to briefly show the 'plug in a charger' icon with a depleted battery graphic and then goes dark.

With the battery attached, PPBUS_G3H = battery voltage = ~11v5.

Attached Files

**salam1** · 09-09-2023, 07:56 AM

Re: Macbook Pro a1708 820-00840 no power

Originally posted by tahakxrd View Post

Hey all,
my macbook a1708 is giving me some issues which im sure on what is causing the issue, i used a thermal camera which showed my u3200 was heating up to 50degrees i have remove that chip and replaced it with similar chip, cd3215c00 however i didnt replace u3100 (unsure if i need to) when trying to power it on i am getting no voltage or amps showing on u3200 on amp meter nor on fuse. however on u3100 its pulling 5v at 0.40ma.
would could be the issue with this?

my previous thread showed 5v 0.4ma on both cd3215.
https://www.badcaps.net/forum/showthread.php?t=100843

It appears like the installation of U3200 didn't fix the issue, and U3100 is drawing power, which suggests that some functionality has been added. Check for solder issues, other damaged components, or board-level problems that may affect the u3200's power supply.