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820-3662 0.32V on PPDCIN_G3H

A

ajdoc

Member
No water damage.
No light on charger so I checked PPDCIN_G3H and got only 0.32V measured on fuse F7005.
With 100% working DC-IN same issue.

Diode mode on PPDCIN_G3H is 0.645V

Any idea where to start?
 
larossmann

larossmann

Administrator
Staff member
Q7180 died. The charger needs to see a load in order to put out voltage, and if Q7180 is dead it won't see a load. One way to confirm this is to cut off a good magsafe 85w cable and attach the ends to a DC power supply, set it to 18.5v, and use that as a charger. It won't care if it sees a load. See if you get any change in activity there.

Also, https://www.youtube.com/watch?v=_LlSuV1JX_w
 
A

ajdoc

Member
Thank you.

I replaced twice Q7180 and still same issue.
When using magsafe via DC power supply got short 0.8V and 0.64A.

Q7180 on gate (pin 6) and source (pin 5) got 0.774V.

Checked R7186 and is correct but R7185 got 1.378K

Removed R7185 and checked and its got 430K.

When Q7180 removed then got no short.
Got 18.4V on source (pin 5) and 6.42V on gate (pin 6) so thats looks OK.
 
Last edited:
A

ajdoc

Member
Yes, there was short on PPDCIN_G3H_CHGR.
One of the tant-poly caps was shorting.

Replaced that and had light on charger/fan spin for around 15 secs and dead again.

This time short was on PPBUS_G3H and Q7135 was shorting.

Replaced that and again was ok for 10-15 secs.

Any idea?
 
S

SMMRepair

Member
Make sure there's no liquid near the CPU regulators...S5_HS_COMPUTING_ISNS will short ppbus as well (i.e. you could have several issues on the board). Common on this model.
 
Last edited:
A

ajdoc

Member
ISL replaced and short gone but still power issue.

On battery: chime, backlight, Apple logo, login screen and shot down.

On battery and 85W charger: light on charger blinking (ON/OFF), fans as well ON/OFF (no chime)
 
larossmann

larossmann

Administrator
Staff member
What is the resistance between pins 17/18 of ISL6259?

What is the resistance between pins 27/28 of ISL6259?

If answer to those questions is 2.2 and 20.02 respectively, then I would check the soldering of the chip.
 
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