820-00239: No powering up

Board isn't powering up. Found corrosion on and around U8190, U1830 and U8192, and Q440. Along with the corrosion, UB400 was cycling on and off. Once the corrosion was cleaned, the cycle was fixed and we now have 20v on all 4 usb-c ports. Also, replaced R1452 due to it being corroded. But the board is still not power up.

Measuring and found

PP3V3_S5 - 0v
PP5V_S5 - 0v
PP5V_S4 - 0v
P5VS5_EN - 0v
smc_pm_g2_en - 3.4

Anything else to check or any suggestions?


Staff member
What is the exact PPBUS_G3H voltage (without battery)?
Is the battery charging?

Check U7800 (7 OF 10) voltages.
PP3V3_S5 - 0
PP3V3_SUS - 0
PP1V8_S3 - 0
S5_PWRGD - 0
PP3V3_S0 - 0
PM_SLP_S4_L - 0
SMC_PM_G2_EN - 3.4
P1V8S3_EN - 0
PP3V0_G3H - 3.1
PP5V_S4 - 0.37


Staff member
"PP5V_PMICLDO - 0.01
Check diode mode to ground.

PPBUS_PMIC is present?
If not, check R7865.
PP1V25_PMICVREF - 0.49

PPBUS_PMIC - 13.07

Not sure what i did before but i remeasured the below with the following voltages.
PP1V25_PMICVREF - 1.25
Found the issue while checking U7650. C7651 was broken off pad 1 side. Once fixed, board now comes to life. Thanks again for the assist.
Now that i have the board working, no usb activity other than a flash upon initial plug in. I do have PP5V_S0 at 5.1v. Any suggestions on what else to check on this board? Could it be related to the corrosion i had cleaned up on and around U8190, U1830 and U8192, and Q440?


Staff member
Do you get 5V at L3500 and LB700?
Test connecting an USB device on corresponding ports.

Mentioned components don't seem to have USB relation.
Diode mode LCD disconnected.
EDP_INT_AUX_N - .285
EDP_INT_AUX_P - .289
EDP_INT_ML_N<0> - .289
EDP_INT_ML_P<0> - .29
EDP_INT_ML_N<1> - .29
EDP_INT_ML_P<1> - .29
EDP_INT_ML_N<2> - .28
EDP_INT_ML_P<2> - .29
EDP_INT_ML_N<3> - .28
EDP_INT_ML_P<3> - .28

checking with a 15" model, (820-00281) those measurements are coming out as .48. Is this pointing to a blown or faulting GPU.
Sorry, I should I’ve also included that theowner had just messaged me that the original issue he had was no image on display. When I got it, it was completely dead until after the repair of the corrosion damage.
Regarding usb2 and 3 testing, other than finding a usb 2.0 and 3.0 device to test, is there another way to test this?
Also The cpu is warm, normal running temp.


Staff member
You should compare EDP_INT readings with similar board, maybe 00923.
00281 has discrete graphics and U9850 analog MUX placed on these lines.

"Now that i have the board working"
Working what, if no USB activity, nor video???
Turned on board is not same like working!

Check L7210 voltage after 10-15 seconds.