JustAnotherGuy
Member
Pin 17/18 - 3 ohm
Pin 27/28 - 20 ohm
C7040 12.58V
Pin 27/28 - 20 ohm
C7040 12.58V
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820-2915-a Spontaneous Shutdown, No Startup
- Thread starter JustAnotherGuy
- Start date
So PPBUS_G3H only fluctuates when F7040/41 are soldered in place?
Looks like SMC issue...
Looks like SMC issue...
JustAnotherGuy
Member
Wait hold on I feel like im missing something here. PPBUS_G3H never fluctuated at any point. Even in the beginning before removing any components, PPBUS_G3H was stable at 12.5V (post #1).
"Pin 23 - 12.25 - 12.75V ... weird interference, matches pulse frequency"
Dropping to 12.25V is sign of non working SMC, or communication problem between SMC and U7000.
Please clarify actual situation.
Only DC readings, forget the o-scope.
Trying to write down too much information, is not always helpful.
Sometime make us to lose the focus.
Dropping to 12.25V is sign of non working SMC, or communication problem between SMC and U7000.
Please clarify actual situation.
Only DC readings, forget the o-scope.
Trying to write down too much information, is not always helpful.
Sometime make us to lose the focus.
JustAnotherGuy
Member
Ok so with the multimeter, which doesn't really update very quickly, it looks around 12.6V on Pin23, though the number moves around a little bit. This is similar to the DC voltage randomly jumping from 0V -> 2.3V -> 0.7V -> 0.2V -> etc etc for pulsing pins.
Fluctuating like 12.4-12.7V will not be a big problem.
But dropping to 12.25V is very bad.
However, you didn't mention such fluctuation at PPBUS_G3H.
But dropping to 12.25V is very bad.
However, you didn't mention such fluctuation at PPBUS_G3H.
JustAnotherGuy
Member
Got it. So since it is in the 12.4 - 12.7V range, what is the next step?
Get steady SMC_PM_G2_EN...
JustAnotherGuy
Member
So based on what you said earlier about the U7000 and SMC, are you suggesting the next thing to do is to replace both components or something? The last concrete step was to remove the fuses.
Check if is possible to cut off trace for pin 12/U7201.
Then check if SMC_PM_G2_EN gets steady high.
Then check if SMC_PM_G2_EN gets steady high.
JustAnotherGuy
Member
It seems like the trace goes under the chip. There is no trace leading out from pin 12 of the U7201.
In an earlier post, you've said to get steady 3V at SMC_PM_G2_EN, if press SMC_ONOFF_L for 3s.
Is that still true?
If yes, check if 3V3_S5 gets steady at same time.
Is that still true?
If yes, check if 3V3_S5 gets steady at same time.
JustAnotherGuy
Member
I am super confused what is going on now because the pulsing frequency has now changed to what looks like 0.2Hz.
So what you stated is true, if I press SMC_ONOFF_L for about 1s (3s would be the same), SMC_PM_G2_EN gets solid 3.5V. 3V3_S5 gets solid 2.1V. 3V3_S5 doesn't look right only having 2.1V...
I have attached 3 images. SMC_ONOFF_L is the blue line in the images, while the yellow is the tested pin.
3V3_S5.png - data capture after a power cycle, and then pressing the SMC_ONOFF_L
SMC_PM_G2_EN.png - after a power cycle, and then pressing the SMC_ONOFF_L
3V3_S5_POWERCYCLE.png - 3V3_S5 immediately after MagSafe power cycle, no SMC_ONOFF_L triggering
SMC_PM_G2_EN_POWERCYCLE.png - SMC_PM_G2_EN immediately after MagSafe power cycle, no SMC_ONOFF_L triggering
So what you stated is true, if I press SMC_ONOFF_L for about 1s (3s would be the same), SMC_PM_G2_EN gets solid 3.5V. 3V3_S5 gets solid 2.1V. 3V3_S5 doesn't look right only having 2.1V...
I have attached 3 images. SMC_ONOFF_L is the blue line in the images, while the yellow is the tested pin.
3V3_S5.png - data capture after a power cycle, and then pressing the SMC_ONOFF_L
SMC_PM_G2_EN.png - after a power cycle, and then pressing the SMC_ONOFF_L
3V3_S5_POWERCYCLE.png - 3V3_S5 immediately after MagSafe power cycle, no SMC_ONOFF_L triggering
SMC_PM_G2_EN_POWERCYCLE.png - SMC_PM_G2_EN immediately after MagSafe power cycle, no SMC_ONOFF_L triggering
Attachments
Please, let o-scope aside; do not complicate the job more than needed.
Post U7201 voltages, when you get steady SMC_PM_G2_EN; pins 23, 12, 13, 22, 29, 21.
If you don't get correct 3V3_S5 in that case, there's something wrong in U7201 area.
Inspect all surrounding resistors and traces; pay atention to R7260/61, R7263 and C7264.
Post U7201 voltages, when you get steady SMC_PM_G2_EN; pins 23, 12, 13, 22, 29, 21.
If you don't get correct 3V3_S5 in that case, there's something wrong in U7201 area.
Inspect all surrounding resistors and traces; pay atention to R7260/61, R7263 and C7264.
JustAnotherGuy
Member
Note for all "cycling" pins the numbers are all approximate (value changes quickly so its whatever I could see at max).
12 - 3.48V
13 - .158V
21 - 3.48V
22 - 1.8 down to 1.7V then cycles 0.25Hz
23 - 1.9 down to 1.7V cycles 0.25Hz
29 - 1V cycles down to 0.8V 0.25Hz
P3V3S5_VFBR_R - spikes to 2V drops to 0V 0.25Hz
P3V3S5_VFBR - spikes 0.6V " "
P3V3S5_DRVH - spikes 1.6V " "
P3V3S5_TG - spikes 2V " "
I don't see anything obviously wrong with components in this area.
12 - 3.48V
13 - .158V
21 - 3.48V
22 - 1.8 down to 1.7V then cycles 0.25Hz
23 - 1.9 down to 1.7V cycles 0.25Hz
29 - 1V cycles down to 0.8V 0.25Hz
P3V3S5_VFBR_R - spikes to 2V drops to 0V 0.25Hz
P3V3S5_VFBR - spikes 0.6V " "
P3V3S5_DRVH - spikes 1.6V " "
P3V3S5_TG - spikes 2V " "
I don't see anything obviously wrong with components in this area.
Attachments
Remove R7978.
Check if symptom changes.
Check if symptom changes.
JustAnotherGuy
Member
12, 13, 21 same as before
22 - 0V
23 - 1.51V solid
29 - 1.7V solid
P3V3S5_VFB2_R - 1.9V solid
P3V3S5_VFB2 - 0.58V solid
P3V3S5_DRVH - 1.9V solid
P3V3S5_TG - 1.9V solid
22 - 0V
23 - 1.51V solid
29 - 1.7V solid
P3V3S5_VFB2_R - 1.9V solid
P3V3S5_VFB2 - 0.58V solid
P3V3S5_DRVH - 1.9V solid
P3V3S5_TG - 1.9V solid
Did you ever get steady SMC_PM_G2_EN?
JustAnotherGuy
Member
Yes. SMC_PM_G2_EN is steady at 3.48V as measured from pin 12 of U7201. Just to note, before and after R7978 removal, pin 12 was at 3.48V solid.
Then PPBUS_G3H is not stable at 12.5V?