820-000165 only works on battery

[Kyle93]

Have a 820-00165 that had mild water damage, primary in dc in area. Using a known good cable and dc in board but have no light. When ac adapter is plugged in backlight comes on for a few seconds and then turns off however if unplugged with just battery backlight stays on along with question mark folder.

u4500 also had mild water damage but do not believe that is the cause of the problem.

pp3v42_g3h is 3.42V

what to check next?

 

[2informaticos]

Does it start in SMC bypass mode?
Do you get amber light with charger, no battery?
Check SCL/SDA lines on battery bus; diode mode to ground and voltage too.
Check J9500 for corrosion and be sure to have good solders.
Post voltage at pins 9 & 15 of ISL6259.
Check exact value for R7121/22 and R7151/52.

 

[Kyle93]

yes starts in SMC bypass mode and backlight doesn't go out

no light whatsoever with or without battery

can you specify what I am looking for when you say check SCL/SDA lines on battery bus? Not sure where to measure for diode mode to ground and voltages

Already fixed J9500 solders and cleaned up corrosion

pin 9 1.435V pin 15 0.80V

R7121 and R7121 11

R7151 2.8 R751 2 .4

 

[2informaticos]

"can you specify what I am looking for when you say check SCL/SDA lines on battery bus?"
Check at pins 4 & 5 of J6950.

Disconnect LIO flex and test the board without battery (just charger), only DC cable connected from LIO board.

Post exact value (measured onboard, ohm scale) for R7180/81 and R7185/86.

 

[Kyle93]

J6950 pin 4 3.4V pin 5 3.4V

diode mode pin 4 .499 pin 5 .498

R7180 99.85 R7181 61.6

r7185 .473 r7186 330.9

 

[2informaticos]

"no light whatsoever with or without battery"
So no MagSafe light at all?
Did you try a known good LIO board/flex?

"pin 9 1.435V"
That is too high.
SMC is informed about 8.5A drawn from charger.
Are you sure about R7121/22 value?.
Measure resistance directly between pins 27/28 of U7100.

 

[Kyle93]

Yes using a known good LIO board/flex. No magsafe light at all

Should the isl be replaced since pin 9 is too high??

yes sure about R7121/22 Value. Just measured again and R7121 starts at 11 and drops to 10.7, same for R7122

Pins 27/28 21 resistance

 

[Kyle93]

pin 9 now .125V after replacing C7102

 

[JohnB8812]

You have an issue with J9500 it seems based on the information you gave. Can you upload a good picture of J9500 mainly pins 19-29? Seems like pins 21 and 27 have issues at minimum.

 

[Kyle93]

[No message]

 

[2informaticos]

Post SMC_DCIN_VSENSE and SMC_PBUS_VSENSE voltage with charger only.

 

[JohnB8812]

Check for continuity from pins 21 and 27 to the rest of the board.

 

[Kyle93]

solved by replacing J9500