A1466 820-000165-A with low PP3v42

[bridges_4u]

Hi mon2,

Sorry. Its been a long time. Encountered an RTA that left me out of action for about 8 months. Just got back on my feet after long sessions of PT. I still have this board and am still interested to find out more about the voltage drop.

1. Which SMBUS pins were your referring to?
2. Are we talking about L7130?

Much appreciated.

Regards

[mon2]

Welcome back. Hope you are feeling better.

Measure the voltage to ground of:

SMBUS_SMC_5_G3_SCL
SMBUS_SMC_5_G3_SDA

CHGR_DCIN (pin # 2 of U7100)

PPDCIN_G3H

[bridges_4u]

mon2 Thank you, mon2. It has been a long time.

Before I took measurements, I found that R7080 was missing. Probably misplaced or removed during the probe. It is a 0 ohm resistor. Would it be fine if I run a jumper wire in place of R7080 for the time being until the replacement arrives so that we could gather the readings?

[bridges_4u]

Welcome back. Hope you are feeling better.

Measure the voltage to ground of:

SMBUS_SMC_5_G3_SCL
SMBUS_SMC_5_G3_SDA

CHGR_DCIN (pin # 2 of U7100)

PPDCIN_G3H

Hi mon2,

Received the replacement 0 Ohm resistor today. Will share the voltages shortly.

Regards

[mon2]

Yes, 0 ohm resistors are essentially jumpers so a blob of solder will also be ok.

[bridges_4u]

Hi mon2

SMBUS_SMC_5_G3_SCL : 3.393
SMBUS_SMC_5_G3_SDA : 3.391V .



CHGR_DCIN : 14.59 V (pin # 2 of U7100)

PPDCIN_G3H : 14.94 V [/QUOTE]

[mon2]

CHGR_DCIN : 14.59 V (pin # 2 of U7100)

PPDCIN_G3H : 14.94 V

Correction: From the following reference - this voltage is ok:

Macbook Power on Sequences - IT-Tech Online

and also from the above:

SMC will use SMBus to communicate with U7100 to adjust the PPBUS_G3H power rail from base voltage 8.1V to the standard voltage 8.45V.

Share the voltage of DCIN_ISOL_GATE to ground.


Are you using the correct power adapter for this laptop?

Remove all power. Meter in resistance mode.

Confirm the resistance of the following resistors:

R7012
R7010
R7011

[bridges_4u]

Are you using the correct power adapter for this laptop?

Remove all power. Meter in resistance mode.

Confirm the resistance of the following resistors:

R7012
R7010
R7011

Hi mon2

YES. I am using the OEM 45watts Magsafe 2 charger.

R7012 : 68K. I had to replace this as it looked a bit off. But I substituted 0402 which is the only package size I got locally. International orders will take upto a month to arrive. So had to resort to this. Should I replace it with the same package size?

R7010 :100K

R7011 : 10 K.

Regards

[mon2]

The resistors are fine. Any fan spin? Does your caps key led toggle?

[bridges_4u]

The resistors are fine. Any fan spin? Does your caps key led toggle?

Hi mon2

No activity whatsoever.

Regards

[bridges_4u]

Correction: From the following reference - this voltage is ok:

Macbook Power on Sequences - IT-Tech Online

and also from the above:



Share the voltage of DCIN_ISOL_GATE to ground.

Hi mon2

DCIN_ISOL_GATE : 6.75V

Regards

[reformatt]

Reviewing this thread, sounds like SMC not running (PPBUS_G3H is low and no light on charger). Check the following:

PP3V42_G3H present @ C5002
PP3V3_S5_SMC_VDDA @ C5001
PP3V3_S5_AVREF_SMC @ C5125
PP1V2_S5_SMC_VDDC @ C5010

(Often have corroded or shorted caps in these areas around the SMC).

SMC_RESET_L should be high
Check for 12Mhz clock at either side of R5110. DC bias from memory is roughly 1V.

If you don't have status LED on the charger, and SYS_ONEWIRE is 3.3V, very likely you need to replace the SMC. You can always try a reflow or reball first, but usually in this state its a dead SMC.

[bridges_4u]

Hi reformatt,

Thank you for jumping in to help. It has been a while that I followed up on this. I shall check for the above said voltages. If I am to replace the SMC, what sources can u recommend to buy donor boards?

mon2 has been helping me all this while and he is awesome. You too.

May i request you to take a look at one of my other threads. I shall post the link to that below.

https://www.badcaps.net/forum/troubl...ng-pulled-down

Regards