HP Envy x360 m, 15m-ee0013dx, GPR51 LA-J493P r2.0, Won't Power On

[Green Probe]

Hello wise friends,
I have a HP Envy x360 m, 15m-ee0013dx, with motherboard GPR51 LA-J493P r2.0 that will not power on. When connected to AC power the charging light turns on to white with no battery, and orange with the battery. When I press the power button I hear a faint click and the charging light turns off for a second, then it turns back on. When the charging light turns off for a second, the powered rails stay on.

I forgot to note that with no battery, no AC, resistance to ground at PRB1 is 147k ohm.
With the battery and AC plugged in, PLB1 goes up to 13v to charge the battery.

Is the 453 ohm resistance at PLM1 okay? Its supplying the RAM. I'm quite new to motherboard repair, but I'm keen to learn. Any guidance is greatly appreciated. Also, I'm still new to the forum, so please let me know if I've made any mistakes in posting, or left out any information. Thanks!

The schematic can be found at: https://www.badcaps.net/forum/troubl...eed-schematics

[mcplslg123]

PLM1 at 453 ohms is ok.
Resistance to GND on U10,pin1-2/6-7/8-9/13-14.Similarly check resistance to GND on U2/U1/U20.

Since you have 3VALW/5VALW, the next thing to come up after power button is RAM voltage at PLM1. As resistance to GND readings is ok on PLM1,there may be short on one of those VS(switched) rails. So report back on those resistance to GND readings.

[Green Probe]

Thank you for your response, Mcplslg123. Here are the readings to GND, as well as a pic of the area the heatsink was covering.



U10
1,2= 4.72k
6,7= 4.78k
8,9= 2.2m
13,14= 3.45k

U2
1,2= 1.86k
3= 3.4m
4= 4.71k
5= .1
6= 5.73m
7,8= 8.67k

U1
1,2= 57.7
3= 4.74k
4= 3.33m
5= 0
6,7,8= 917


U20
1= 4.08k
2= 0
3= 4.29m
4= 100k
5= 4.72k

[Green Probe]

PLM1 at 453 ohms is ok.
Resistance to GND on U10,pin1-2/6-7/8-9/13-14.Similarly check resistance to GND on U2/U1/U20.

Since you have 3VALW/5VALW, the next thing to come up after power button is RAM voltage at PLM1. As resistance to GND readings is ok on PLM1,there may be short on one of those VS(switched) rails. So report back on those resistance to GND readings.

mcplslg123 I also checked voltages on the pins after pressing the power button. Here is the updated list:

U10 (EM5209VF)
1,2= 4.72k 3.3V
3= 90.5K 0v
4= 4.8K 5V
5= 90.5K 0v
6,7= 4.78k 5V
8,9= 2.2m 0v
10= 5.2m 0v
11= 0 0v
12= 4.54m 0v
13,14= 3.45k 0v

U2 (A0Z1336)
1,2= 1.86k 0v
3= 3.4m 0v
4= 4.71k 5v
5= .1 0v
6= 5.73m 0v
7,8= 8.67k 0v

U1 (AOZ1334DI-02)
1,2= 57.7 0v
3= 4.74k 0v
4= 3.33m 5v
5= 0 0v
6,7,8= 917 0v


U20 (SY6288C20AAC)
1= 4.08k 0v
2= 0 0v
3= 4.29m 0v
4= 100k 0v
5= 4.72k 3.3v

PU301 (SY8388BRHC)
1= 2M 6.66V
2,3,4= 4.95K 13.2V
5= 4.7K 3.3V
6= 0 0V
7= 135K 3.3V
8= 105K 2.6V
9= 56.5K 2.6V
10= 3.7M 0.7V
11= 4.7K 3.3V
12= 2.46M 0.4V
13= 39.7K 3.3V
14= 0 0V
15,16= 4.7K 3.3V

If anyone has any suggestions, please let me know. Thanks!

[mcplslg123]

Pu301 is working fine. problem is missing Enable on U10.So you have SUSP# missing. Trace it out in schematic and give your readings.

[Green Probe]

Pu301 is working fine. problem is missing Enable on U10.So you have SUSP# missing. Trace it out in schematic and give your readings.

Forgive me if I'm missing something obvious, as I'm still learning to read schematics. I'm having a hard time making sense of the EC pinout. My board has ENE KB9542Q-E with 128 pins, while the schematic shows a KB9542G-B_VFBGA124.
The only mention of a source for SUSP# seems to be from EC Pin 116 Output in the Power Sequence (Page 5). And mentioned again on EC Pin B7? (Page 58)
When testing resistance from U10 Pin 5 to the EC, the lowest I get is 2.5 ohms to EC Pin 74.
GND to EC Pin 74 is 90.6k.

U10 Pin5 to EC Pin 116 is 140.5k
GND to ECC Pin 116 is 11.7k

Is this a variation that doesn't exactly apply to my board, or am I missing something? Is the EC supposed to be producing SUSP#? Thanks for your time and help!

[mcplslg123]

The two EC's you mentioned are way different(one is BGA)-sp pinouts also differ. You cant troubleshoot without exact schematic.However, you can grab another schematic with KB9542 and check the pins.As far as SUSP# is concerned yes it comes out of SIO. A missing SUSP# may lead to a bad SOC as well.