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Search: Posts Made By: kingskie
Forum: Troubleshooting Laptops, Tablets, and Mobile Devices 08-05-2022, 11:17 PM
Replies: 6
Views: 127
Posted By kingskie
Re: 820-01987 no backlight when wake up from sleep

update:

i change Q8400 and the problem solved.

thanks for the help @mon2
Forum: Troubleshooting Laptops, Tablets, and Mobile Devices 08-05-2022, 10:20 PM
Replies: 6
Views: 127
Posted By kingskie
Re: 820-01987 no backlight when wake up from sleep

hi @mon2,

these are my measurements:
PPBUS_G3H = 12.58V
PPVIN_S0SW_LCDBKLT_R = 12.58V
BKLT_SD = 0V
LCDBKLT_EN_L = 0V

the value for R8402 and R8401 is normal.
Forum: Troubleshooting Laptops, Tablets, and Mobile Devices 08-05-2022, 04:24 AM
Replies: 6
Views: 127
Posted By kingskie
Re: 820-01987 no backlight when wake up from sleep

hi @mon2,

update:
now the backlight is fully off even after dissconnect the battery. what should i check first?
Forum: Troubleshooting Laptops, Tablets, and Mobile Devices 08-05-2022, 03:54 AM
Replies: 6
Views: 127
Posted By kingskie
Re: 820-01987 no backlight when wake up from sleep

when no backlight after wake up from sleep mode, i turn off the macbook with power button and then try to power on with power button again. and still no backlight.
but if i disconnect the battery...
Forum: Troubleshooting Laptops, Tablets, and Mobile Devices 08-05-2022, 02:51 AM
Replies: 6
Views: 127
Posted By kingskie
820-01987 no backlight when wake up from sleep

Hello,

I have a problem with 820-01987 that has no backlight when wake up from sleep. before there was water damage around U6903 and backlight caps. no corrosion found so i just clean it up. is...
Forum: Troubleshooting Laptops, Tablets, and Mobile Devices 06-22-2022, 10:54 PM
Replies: 12
Views: 756
Posted By kingskie
Re: 820-00840 dead 19.7v and 0.01A

update.. i found the short..it is C2977. but i lost some components when i open the shield. it is D3411, C3408 and D3403..is it ok if i dont replace the missing components regarding is is a supported...
Forum: Troubleshooting Laptops, Tablets, and Mobile Devices 06-22-2022, 10:22 PM
Replies: 12
Views: 756
Posted By kingskie
Re: 820-00840 dead 19.7v and 0.01A

update for this problem, i replaced U7000 but still no luck..checked again and found out that PP3V3_TBT_X_F is shorted but i check the others PP3V3 line are not shorted..

any suggestion?
Forum: Troubleshooting Laptops, Tablets, and Mobile Devices 05-14-2022, 12:25 AM
Replies: 26
Views: 1,345
Posted By kingskie
Re: 820-01521 only shows 5V 0.04A

i2c_pwr_sda = 1.791v
i2c_pwr_scl = 1.790v
Forum: Troubleshooting Laptops, Tablets, and Mobile Devices 05-12-2022, 09:00 PM
Replies: 26
Views: 1,345
Posted By kingskie
Forum: Troubleshooting Laptops, Tablets, and Mobile Devices 05-12-2022, 08:59 PM
Replies: 28
Views: 837
Posted By kingskie
Forum: Troubleshooting Laptops, Tablets, and Mobile Devices 05-10-2022, 10:17 PM
Replies: 28
Views: 837
Posted By kingskie
Re: macbook pro 820-00840 have image no backlight

yes @mon2 all the parts are there. the bank pads is no stuff in the schematic.
Forum: Troubleshooting Laptops, Tablets, and Mobile Devices 05-10-2022, 09:44 PM
Replies: 28
Views: 837
Posted By kingskie
Forum: Troubleshooting Laptops, Tablets, and Mobile Devices 05-10-2022, 09:32 PM
Replies: 26
Views: 1,345
Posted By kingskie
Re: 820-01521 only shows 5V 0.04A

pp1v1_upc_xa_ldo_bmc = 1.114v

pp1v1_upc_xb_ldo_bmc = 1.112v
Forum: Troubleshooting Laptops, Tablets, and Mobile Devices 05-10-2022, 04:18 AM
Replies: 26
Views: 1,345
Posted By kingskie
Re: 820-01521 only shows 5V 0.04A

yes @mon2, i measure with dioda mode red probe on the ground and black probe on the test point
Forum: Troubleshooting Laptops, Tablets, and Mobile Devices 05-10-2022, 03:00 AM
Replies: 26
Views: 1,345
Posted By kingskie
Re: 820-01521 only shows 5V 0.04A

this is my multimeter
Forum: Troubleshooting Laptops, Tablets, and Mobile Devices 05-09-2022, 10:21 PM
Replies: 26
Views: 1,345
Posted By kingskie
Re: 820-01521 only shows 5V 0.04A

i checked USBC_XB_SBU2 from the test point that i attached still OL
USBC_XB_SBU1 = OL
USBC_XA_SBU1 = OL
USBC_XA_SBU2 = OL
Forum: Troubleshooting Laptops, Tablets, and Mobile Devices 05-09-2022, 08:30 AM
Replies: 28
Views: 837
Posted By kingskie
Re: macbook pro 820-00840 have image no backlight

this is the pic of the board that i am working on. 820-0040
Forum: Troubleshooting Laptops, Tablets, and Mobile Devices 05-09-2022, 04:36 AM
Replies: 26
Views: 1,345
Posted By kingskie
Forum: Troubleshooting Laptops, Tablets, and Mobile Devices 05-09-2022, 04:33 AM
Replies: 28
Views: 837
Posted By kingskie
Re: macbook pro 820-00840 have image no backlight

sorry my mistake. i measured wrong current sense resistor.

the current sense resistor is R8400 right?
the resistance between the fuse and the current sense resistor is 0.5 ohm
the voltage at the...
Forum: Troubleshooting Laptops, Tablets, and Mobile Devices 05-09-2022, 02:22 AM
Replies: 28
Views: 837
Posted By kingskie
Re: macbook pro 820-00840 have image no backlight

voltage after fuse 13V
voltage before current sense resistor 5V
voltage after current sense resistor 5V
Q8401
pin 1-3 = 0.056V
pin 4 = 0V
pin 5 = 0.009V
Forum: Troubleshooting Laptops, Tablets, and Mobile Devices 05-06-2022, 10:01 PM
Replies: 28
Views: 837
Posted By kingskie
Re: macbook pro 820-00840 have image no backlight

plugged the adapter to turn on...shorted the R8402 pin 1 but still no sign of backlight..
changed again the U8400 but still the same...
after change U8400 BKLT_EN_R is 3.3V but still no backlight
Forum: Troubleshooting Laptops, Tablets, and Mobile Devices 05-05-2022, 10:38 PM
Replies: 28
Views: 837
Posted By kingskie
Re: macbook pro 820-00840 have image no backlight

R8450 = 0.2 ohm
R8451 = 0.2 ohm
backlight caps resistance to ground = 164K with lcd
without lcd from couple M go down to K and then OL and repeat again couple M and so on.

by force you mean...
Forum: Troubleshooting Laptops, Tablets, and Mobile Devices 05-05-2022, 09:12 PM
Replies: 28
Views: 837
Posted By kingskie
Re: macbook pro 820-00840 have image no backlight

sigh, still no backlight. should i try change U8400 again?
Forum: Troubleshooting Laptops, Tablets, and Mobile Devices 05-05-2022, 06:35 AM
Replies: 28
Views: 837
Posted By kingskie
Re: macbook pro 820-00840 have image no backlight

so, without take off u8400,
1. remove R8442
2. inject 3v3 on C8442 pin 1
3. turn on the macbook to see whether the backlight is on or not..

are the steps correct?
Forum: Troubleshooting Laptops, Tablets, and Mobile Devices 05-05-2022, 04:12 AM
Replies: 28
Views: 837
Posted By kingskie
Re: macbook pro 820-00840 have image no backlight

just curious, can i get 5v7 on the gate even without backlight ic (U8400)?
Showing results 1 to 25 of 145

 
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