820_3115 b a1278 No power


New member
When it got here the first time Trackpad was not working so we inyected voltage to u5805 , Got hot , after that , the mb stopped turning on.

have this Right Now
- Green Light on
- PSU consumes 0.01A
- PP5V_S3= 0
- P5VS3_EN_L=3.42 , but P5VS3_ENTRIP=0
- 5V3V_REG_EN= 3.22 , but PP5VS5_LDO=0
- P5VP3V3_REG3=0

What could it be?
Is it possible to turn it on without u5805


Staff member
First of all, welcome to the forum!

Injected voltage on U5805 which pin and why???

Post diode mode to ground at 5V_S5.
If short (or low value), remove R5805, L5800 and check again.
Do you get 3V3_S5/SUS?


New member
Thanks for the welcoming.

Injected in pin 1 to see if it strated to get hot. Which it did.

5V_S5 is not in Short . value reads 630 in diode mode.

3V3_S5/SUS = 0.36


New member
Update: It turns on but no Video nor USB activity :( . Tried another Bios too and no help.
Im getting theses values.

L7510/20 = 1.12V



mem_reset_L = 1.5V

Is it possible that CPU is bad?


Staff member
You must discard other options first.

When board really boots, VCORE should drop from 1.12V to 0.78V aprox.
Try one good DDR module at a time, each slot.
Be sure all resistors around U7400 are good, as traces too.
Check all SPI Bus Series Termination resistors and traces.
Finally, heat PCH and/or CPU with good flux; no more than 180-200 degrees, for 15-20s.