I'm troubleshooting this board that is in good condition, no liquids damage, no corrosion, no bad caps that I can see, nothing getting warm. Previous owner said it just powered off and would not charge. The board negotiates 20V from a PD charger. This is not a power-in failure.
I don't have an inline volt/amp meter for USB-C, so I continued by using a 5V Anker power bank (PD) and inline 5V meter to see amperage. There is no current draw, only a blip of 10mA every 15 seconds or so (without battery). With battery, the boards goes to 0.4A, shortly cuts out, then goes to 1.8A, which looks like it's charging fine.
Rails I have measured:
PPDCIN_E85_SS is 20V on PD, 5.1V on Anker powerbank
PPBUS_G3H = 8.6V
PP3V3R3V0_AON = 3.28V
PP5V_S4 = 4.995V
P5V_S4_PGOOD = 3.3V
PP3V3_S4 = 0V (70K to gnd, goes to 0.07V three seconds after plugging in power, then gradually goes to 0V in about five seconds)
P3V3_S5 = 3.3V
P3V3_S5_PHASE = 3.3V
PM_SLP_S5_L = 3.3V
PP1V2_S3, PP1V8_S3, PDDR_S3_PHASE = 0V
PPVCC_S0_CPU = 0V
PP1V05_SUS = 1.05V
Considering that P3V3_S5 is VIN for U8000 and PM_SLP_S5_L is the trigger, PP3V3_S4 should be 3.3V (but isn't). U8000 is not damaged.
I am aware of the CPU failures. This is a personal laptop.
Will be glad to look for more clues if needed.
I don't have an inline volt/amp meter for USB-C, so I continued by using a 5V Anker power bank (PD) and inline 5V meter to see amperage. There is no current draw, only a blip of 10mA every 15 seconds or so (without battery). With battery, the boards goes to 0.4A, shortly cuts out, then goes to 1.8A, which looks like it's charging fine.
Rails I have measured:
PPDCIN_E85_SS is 20V on PD, 5.1V on Anker powerbank
PPBUS_G3H = 8.6V
PP3V3R3V0_AON = 3.28V
PP5V_S4 = 4.995V
P5V_S4_PGOOD = 3.3V
PP3V3_S4 = 0V (70K to gnd, goes to 0.07V three seconds after plugging in power, then gradually goes to 0V in about five seconds)
P3V3_S5 = 3.3V
P3V3_S5_PHASE = 3.3V
PM_SLP_S5_L = 3.3V
PP1V2_S3, PP1V8_S3, PDDR_S3_PHASE = 0V
PPVCC_S0_CPU = 0V
PP1V05_SUS = 1.05V
Considering that P3V3_S5 is VIN for U8000 and PM_SLP_S5_L is the trigger, PP3V3_S4 should be 3.3V (but isn't). U8000 is not damaged.
I am aware of the CPU failures. This is a personal laptop.
Will be glad to look for more clues if needed.