Lenovo Ideapad S145 GS440&GS540 NMC511 Rev 1.0 / No power and no LED lights
This motherboard has no signs of life, none of the LED's light up neither the power button does something.
i measured some of the resistances and voltages:
112ohm 1.2v
75ohm 0.9vs
6 ohm vddc_vdd and vddcr_soc
13k ohm 5valw_p
3k ohm 3valw_p
21k ohm 780S_LX
voltages without a battery and without a CMOS:
3.3v at 3valw_p and +3VL_EC
3.8v at 5valw_p
9v at 780s_lx
0v at EC_APU_ALWEN, 0.9VS, EC_VR_ON, EC_ON_L (no resistor installed at RE104 so i don't know if it even should come up), ALW_PWRGD and 1.2v
1.5v at APU_LPC_RST#
1.3v at LV5075_CS
i suspected PU3501 and changed it from a donor board but nothing changed.
sometimes all voltages die and V20B goes to PQ205 which then outputs only 0.2v
where to go from here?
i measured some of the resistances and voltages:
112ohm 1.2v
75ohm 0.9vs
6 ohm vddc_vdd and vddcr_soc
13k ohm 5valw_p
3k ohm 3valw_p
21k ohm 780S_LX
voltages without a battery and without a CMOS:
3.3v at 3valw_p and +3VL_EC
3.8v at 5valw_p
9v at 780s_lx
0v at EC_APU_ALWEN, 0.9VS, EC_VR_ON, EC_ON_L (no resistor installed at RE104 so i don't know if it even should come up), ALW_PWRGD and 1.2v
1.5v at APU_LPC_RST#
1.3v at LV5075_CS
i suspected PU3501 and changed it from a donor board but nothing changed.
sometimes all voltages die and V20B goes to PQ205 which then outputs only 0.2v
where to go from here?