820-00923 5v only

[tcampbell34]

Hello. I have a 820-00923 that was liquid damaged but it has been previously worked on and cleaned so I don't know where exactly the liquid damage was. Amp meter shows 5v 0.03a on all 4 ports, but 2 of the ports power cycle every couple seconds and then other 2 do not. I know if the port shows steady 5v instead of cycling, that there is an issue on the corresponding CD3215 chip, but I have replaced both CD3215 chips for the ports that are steady 5v and have gotten no change. I replaced each one twice just to be safe but they still show steady 5v 0.03a. Diode mode values on each of the CD3215 chips seem similar so not sure where to check next. Here are some voltage and diode mode measurements.

U3100 (Steady 5v):
PP3V3_G3H - 3.32v - 0.337
PP20V_USBC_XA_VBUS - 5.17v - 0.16
PP3V3_UPC_XA_LDO - 3.29v - 0.476
PP1V8_UPC_XA_LDOA - 1.78v - 0.484
PP1V8_UPC_XA_LDOD - 1.8v - 0.449
PP1V1_UPC_XA_LDO_BMC - 0v - 0.464

U3200 (5v loop):
PP3V3_G3H - 3.34v - 0.337
PP20V_USBC_XB_VBUS - 5.17v - 0.16
PP3V3_UPC_XB_LDO - 3.29v - 0.476
PP1V8_UPC_XB_LDOA - 1.8v - 0.491
PP1V8_UPC_XB_LDOD - 1.8v - 0.457
PP1V1_UPC_XB_LDO_BMC - 1.1v - 0.47

UB300 (5v loop):
PP3V3_G3H - 3.34v - 0.337
PP20V_USBC_TA_VBUS - 5.17v - 0.159
PP3V3_UPC_TA_LDO - 3.3v - 0.476
PP1V8_UPC_TA_LDOA - 1.8v - 0.492
PP1V8_UPC_TA_LDOD - 1.8v - 0.459
PP1V1_UPC_TA_LDO_BMC - 1.1v - 0.476

UB400 (Steady 5v):
PP3V3_G3H - 3.34v - 0.337
PP20V_USBC_TB_VBUS - 5.1v - 0.159
PP3V3_UPC_TB_LDO - 3.28v - 0.475
PP1V8_UPC_TB_LDOA - 1.8v - 0.511
PP1V8_UPC_TB_LDOD - 1.8v - 0.472
PP1V1_UPC_TB_LDO_BMC - 1.1v - 0.496

 

[2informaticos]

Seems to have a problem on U3100 area; doesn't have 1V1 LDO.
Be aware of new chips from China, many fake...

Do you get SMC_RESET_L?

 

[tcampbell34]

Yea SMC_RESET_L is 3.3v. I will check U3100 again and see if I can find any issues.