HP Pavilion 14-DH no power no led faroe_dis_x32_mb_mv 18742-1

[reset1986]

hi all, i have this hp with faroe_dis_x32_mb_mv 18742-1 motherboard

Virtually dead, not even the white / orange LED on the power connector lights up

motherboard checked there is no corrosion, all mosfets are ok, there are no shorts
I find only
19Vcc
ADP_ID 0.35v

i can't find the wiring diagram

what you can check, any suggestions are appreciated

thank you

[mon2]

Re: HP Pavilion 14-DH no power no led faroe_dis_x32_mb_mv 18742-1

Adapter ID pin voltage is too low.

Reference:
https://yashan.co.in/hp-cq40-battery...g-discription/

[reset1986]

Re: HP Pavilion 14-DH no power no led faroe_dis_x32_mb_mv 18742-1

Adapter ID pin voltage is too low.

Reference:
https://yashan.co.in/hp-cq40-battery...g-discription/

ok, I exclude the power supply because it is working, could it be the kbc that pulls the voltage down? or some resistance,
then adp id should be higher than 2v to make the leds light up?

[mcplslg123]

Re: HP Pavilion 14-DH no power no led faroe_dis_x32_mb_mv 18742-1

ADP_ID varies between mb . It depends on the resistor used as voltage divider, which again is different in different mb's. So there is no constant/benchmark voltage for ADP_ID. However, most of the mb works between 0.6V-1.2V. You can try injecting 0.9V on ADP_ID pin to see if mb triggers on.

DC Jack light not glowing can be for several reasons like bad sio chip/ec firmware/Missing +3V LDO etc. So you need to troubleshoot the basics. Check dc-in mosfets for voltage on S-D-G pins.

[reset1986]

Re: HP Pavilion 14-DH no power no led faroe_dis_x32_mb_mv 18742-1

ADP_ID varies between mb . It depends on the resistor used as voltage divider, which again is different in different mb's. So there is no constant/benchmark voltage for ADP_ID. However, most of the mb works between 0.6V-1.2V. You can try injecting 0.9V on ADP_ID pin to see if mb triggers on.

DC Jack light not glowing can be for several reasons like bad sio chip/ec firmware/Missing +3V LDO etc. So you need to troubleshoot the basics. Check dc-in mosfets for voltage on S-D-G pins.

the adp id signal is around 0.45v,

i found 2 ic:

SY8288CRAC which manages the 5v

SY8286BRAC
gestsce i 3v

on SY8288c I find the 19V on pin 2345 IN,
9v pin 11 EN2
4.80V on pin 15 LDO (+ 5VPCU)

on ic SY8286BRAC

19V pin IN 2345
9V pin 11 EN2

0.2V pin 17 LDO (+ 3vpcu)

replaced ic SY8286B to get + 3vpcu
but the situation does not change, I always measure 0.2 / 0.3V

advice?

[reset1986]

Re: HP Pavilion 14-DH no power no led faroe_dis_x32_mb_mv 18742-1

i isolated the 3vpcu line from the source IC from the other components, this is connected through a 0 ohm resistor,
now i get the 3vpcu, from the ic source side,

this signal powers many components including diodes and kbc,
strange thing I raised two diodes that are crossed by 3vpcu, now the led lights up I measure the charge at 12v, the button if I press the power led lights up for 10 seconds and then turns off, if I apply the diodes I lose the 3vpcu


working diodes

[mcplslg123]

Re: HP Pavilion 14-DH no power no led faroe_dis_x32_mb_mv 18742-1

What is the resistance on both pads of that 0 ohms resistor??. One of the pad(output side) is having low resistance. U need to inject 1V on the pad showing low resistance(assuming u have a dc supply). Most likely kbc chip will heat up. Put those diodes back as applying power with missing components can be risky. However, test the diodes out of circuit before putting them back.

[reset1986]

Re: HP Pavilion 14-DH no power no led faroe_dis_x32_mb_mv 18742-1

What is the resistance on both pads of that 0 ohms resistor??. One of the pad(output side) is having low resistance. U need to inject 1V on the pad showing low resistance(assuming u have a dc supply). Most likely kbc chip will heat up. Put those diodes back as applying power with missing components can be risky. However, test the diodes out of circuit before putting them back.

Diodes are good,
measured resistance on the pads res 0 ohm,

side ic source
red tip to ground I measure 130 kohm

black tip to ground
I measure infinity

kbc component side pad

red to ground I measure 8 kohm

black to ground I measure 4kohm

tomorrow i try to inject 1v kbc side to see how it behaves