Macbook Pro A1297 Unibody 2009..No Power

[Joandaz]

Hi members new here to Badcaps and new to board diagnostics
The unit unit will not power up.
Mac Board 820=2610=A
The connected mag safe shows a green led
Have removed the logic board,no visible sign of cap damage,or liquid spill.
I have measured the fan jack J5650 and J5660 at pin 1
No voltage so I believe we have a PP5V_S0 rail issue
Schematics PP3V3_S0 identifies the mosfet Q7930 6 Pin should have 4 legs 1,2,5,6 at 3.3 volts.
Measuring zero volts on these legs
Legs 3,4 are powered and measure 3.3 volts from the PP3V3_S5 and PP3V3S0_SS.
Am I able to conclude that the mosfet is faulty and is the source of the problem.
Please guide this nube
Very new at troubleshooting..please excuse my ignorance
Common issue Tantalum Cap C771 was tested good.

[mon2]

Re: Macbook Pro A1297 Unibody 2009..No Power

Welcome.

What are the readings on each leg D6905?

Also post the values for the 2nd attached graphic.

[Joandaz]

Re: Macbook Pro A1297 Unibody 2009..No Power

Welcome.

What are the readings on each leg D6905?

Thanks Mon,I edited the post as I was stupidly reading the wrong schematic the rail PP5V_S0 at pin 1 on the fan connector reads zero volts..Will look at your thumbnail and come back...thank you

[Joandaz]

Re: Macbook Pro A1297 Unibody 2009..No Power

Welcome.

What are the readings on each leg D6905?

Also post the values for the 2nd attached graphic.

Mon, thank you here are the measurements
Diode D6905
Voltage ground to leg 1 is 18.95v
Voltage ground to leg 2 is 8.67v
Voltage ground to leg 3 is 18.67v

Resistor R6911
Leg 2 of the resistor to test point TP1 PP18V5DC in onewire 11.08 V
TP1 PP18V5DC to TP1 Onewire Pwr En L Div 19.1 V

[piernov]

Re: Macbook Pro A1297 Unibody 2009..No Power

Even if it looks good, C7771 should be replaced nonetheless.
No point in troubleshooting one-wire circuit and charging circuit if green light and S5 rails are present.
As all MacBooks with NVidia MCP, power button must be triggered to turn on the machine.
And as always when troubleshooting a power issue, the list of power rails must be followed to measure voltage on every power rails.

[Joandaz]

Re: Macbook Pro A1297 Unibody 2009..No Power

Even if it looks good, C7771 should be replaced nonetheless.
No point in troubleshooting one-wire circuit and charging circuit if green light and S5 rails are present.
As all MacBooks with NVidia MCP, power button must be triggered to turn on the machine.
And as always when troubleshooting a power issue, the list of power rails must be followed to measure voltage on every power rails.

Thank you Pernov...Louis Rossmann has a great Youtube clip on understanding power rail sequence..I have no power on the PP5V_S0, together with a number of shorted caps on the PPVCORE_S0...do you think it would be ok to inject a low voltage and current into the rail to find the shorted component

[mon2]

Re: Macbook Pro A1297 Unibody 2009..No Power

Please post the resistance to ground on these rails.

It is common for low readings for the vcore (low voltage) rail.

[Joandaz]

Re: Macbook Pro A1297 Unibody 2009..No Power

Thanks Mon
Resistance to ground readings
Pin 1 Fan jack PP5V
J5650 is 1.4 M ohms
J5660 is 1.2 m ohms
Vcore caps C7562 C7568 C7564 are 4.0 ohms

[mon2]

Re: Macbook Pro A1297 Unibody 2009..No Power

Hi. What is the resistance to ground on PP3V3_S0_FET?

Q7930 may be damaged.

[Joandaz]

Re: Macbook Pro A1297 Unibody 2009..No Power

Hi. What is the resistance to ground on PP3V3_S0_FET?

Q7930 may be damaged.

Evening Mon, whilst checking the voltage on the Fet Legs Q7930 PP3V3_SO the PPBUS_G3H Fet Q4260 started to fry..cap looks burnt too
Will have to source a donor board and come back to you

[Stephen]

Re: Macbook Pro A1297 Unibody 2009..No Power

What Piernov said, I would start out replacing C771 first with the proper Tantalum Cap. Usually in MOST cases this solves the no power issue for these 2009 boards. Once that is replaced also double check your power button works.

We replaced a bad cap on this board and still had no voltage when we pressed the power button, we used a temp Keyboard and voila it turned on. Just make sure you do that as well, it seems to be common for these boards to fail with that cap and in some cases the cap is bad and the power button fails as well. Hope this helps.

[tata123]

Re: Macbook Pro A1297 Unibody 2009..No Power

check if SMC is OK, put your Battery on and off, if LED turn from Green to Orange, if this is ok, check rails and post here!!

[Joandaz]

Re: Macbook Pro A1297 Unibody 2009..No Power

Evening Mon, whilst checking the voltage on the Fet Legs Q7930 PP3V3_SO the PPBUS_G3H Fet Q4260 started to fry..cap looks burnt too
Will have to source a donor board and come back to you

I continue to wade through the schematics to find why the PP5V_S0 rail is missing.
I understand that PP5V_S0 is generated from U7500
I am not seeing a voltage on P5V RTS0_EN and tracing the output back to PM_SLP_S4_L
Am I chasing rabit holes?

[mon2]

Re: Macbook Pro A1297 Unibody 2009..No Power

What are the voltage readings for the following rails (3 of them) as per attached table?

[Joandaz]

Re: Macbook Pro A1297 Unibody 2009..No Power

What are the voltage readings for the following rails (3 of them) as per attached table?

Mon ..thank you again
PM_SLP_S4_L no voltage at Q7912
PM_SLP_S3_L 3.32 v at Q3801
SMC_PM_G2_EN 3.38 v at TP(1)SMC_PM_G2_EN

Directions out of the burrow please

[mon2]

Re: Macbook Pro A1297 Unibody 2009..No Power

PM_SLP_S4_L appears to be linked to U1400. Wonder if that is defective but too early to tell.

Can you post the readings for the attached points of interest?

[Stephen]

Re: Macbook Pro A1297 Unibody 2009..No Power

Ouch U1400 doesn't sound pleasant. Dead CPU no bueno. Not worth repairing at that point. You could buy a no power logic board on eBay with a failed CAP for next to nothing and just replace the cap and have a working board.

[piernov]

Re: Macbook Pro A1297 Unibody 2009..No Power

PM_SLP_S4_L should come up at the same time or before PM_SLP_S3_L.
U1400 is the MCP.

[Joandaz]

Re: Macbook Pro A1297 Unibody 2009..No Power

PM_SLP_S4_L appears to be linked to U1400. Wonder if that is defective but too early to tell.

Can you post the readings for the attached points of interest?

Mon little confusing between schematics and board view.
PP3V3_S0_P3V3S0FET on the board view measured between R7932 PIN 1 and C7931 Pin 1 board view shows rail PP3V3_ S5 at these components
If correct PP3V3_S0_P3V3S0FET location 1 measures 0 volts
P3V3S0_EN Pin 5 Q7912 location 2 measures 0 volts
PP3V3_S0_FET Pin 6 Q7930 location 3 measures 0 volts
P3V3S0_EN_L location 4 measured between R7930 Pin 2 and R7930 Pin 1 measures 3.28 volts
Trust this makes some sense
Losing confidence my end

[Stephen]

Re: Macbook Pro A1297 Unibody 2009..No Power

PM_SLP_S4_L should come up at the same time or before PM_SLP_S3_L.
U1400 is the MCP.

Oops I got the U1400 backwards with a Mid 2009 13" cpu