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[SOLVED] 820-3332 no green/orange light
- Thread starter aurel476
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The first thing is why is PP3V42_G3H 2.9v instead of 3.425v? That isn't right at all.
PPBUS_G3H being 12.23v means the SMC is not running. Is SMC_RESET_L 3.42v? Does the SMC seem corroded? What is diode mode on pin 2 of on R5280 and R5281, with red probe on ground?
PPBUS_G3H being 12.23v means the SMC is not running. Is SMC_RESET_L 3.42v? Does the SMC seem corroded? What is diode mode on pin 2 of on R5280 and R5281, with red probe on ground?
Well first you need to get PP3V42_G3H to be 3.42v before anything else will work, so let's focus on that.
With an original 85w charger plugged in:
1) What voltage do you get at pin 1 of R6920?
2) What voltage do you get at pin 2 of R6920?
3) What voltage do you get at pin 8 of U6990?
IF you get anything less than 16v at any of these points, remove power from the meter and measure:
1) What is resistance to ground at pin 6 of U6990?
2) What is resistance to ground at pin 2 of L6995?
With an original 85w charger plugged in:
1) What voltage do you get at pin 1 of R6920?
2) What voltage do you get at pin 2 of R6920?
3) What voltage do you get at pin 8 of U6990?
IF you get anything less than 16v at any of these points, remove power from the meter and measure:
1) What is resistance to ground at pin 6 of U6990?
2) What is resistance to ground at pin 2 of L6995?
Can you use a decimal point instead of a comma for voltages? You're making my eyes bleed reading that.
It seems like there is a short circuit on PP3V42_G3H. This will be difficult to find because at 124 ohms it will only use up something like 0.1 watts which will produce virtually no heat at all. Your job here is to inject 3.42v into PP3V42_G3H and find what gets hot, but without some sort of expensive thermal camera or freeze spray that will be very difficult to do.
It seems like there is a short circuit on PP3V42_G3H. This will be difficult to find because at 124 ohms it will only use up something like 0.1 watts which will produce virtually no heat at all. Your job here is to inject 3.42v into PP3V42_G3H and find what gets hot, but without some sort of expensive thermal camera or freeze spray that will be very difficult to do.
This is a discrepancy in measurements.
On one hand, the SMC is getting hot and it is taking 0.47 amps on PP3V42_G3H.
On the other hand, there is 124000 ohms to ground on PP3V42_G3H.
It is highly unlikely these two can both be true at the same time. You said earlier that PP3V42_G3H had 124 ohms to ground, and that makes far more sense when combined with the rest of the available information. This is supported by the fact that the SMC gets hot.
However, you have also said that replacing the SMC does not fix the issue of the SMC getting hot. This makes absolutely no sense and brings us back to square one, unless you are replacing it with other bad SMCs, or soldering it very improperly, which is possible.
I would remove the SMC and see how many amps PP3V42_G3H is using without the SMC. Wick the pads so no residual solder is causing a short. With the SMC removed, how many amps are pulled injecting 3.42v into PP3V42_G3H?
On one hand, the SMC is getting hot and it is taking 0.47 amps on PP3V42_G3H.
On the other hand, there is 124000 ohms to ground on PP3V42_G3H.
It is highly unlikely these two can both be true at the same time. You said earlier that PP3V42_G3H had 124 ohms to ground, and that makes far more sense when combined with the rest of the available information. This is supported by the fact that the SMC gets hot.
However, you have also said that replacing the SMC does not fix the issue of the SMC getting hot. This makes absolutely no sense and brings us back to square one, unless you are replacing it with other bad SMCs, or soldering it very improperly, which is possible.
I would remove the SMC and see how many amps PP3V42_G3H is using without the SMC. Wick the pads so no residual solder is causing a short. With the SMC removed, how many amps are pulled injecting 3.42v into PP3V42_G3H?
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Ok, we're getting somewhere. So short circuit present with SMC on, short circuit gone with SMC off.
One of two things is possible:
1) You put on another bad SMC.
2) The SMC you put on was good but you used too much heat removing it from the old board/reballing/soldering it onto the new board.
So I would say find another SMC and put it on there.
One of two things is possible:
1) You put on another bad SMC.
2) The SMC you put on was good but you used too much heat removing it from the old board/reballing/soldering it onto the new board.
So I would say find another SMC and put it on there.
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