820-01987 with low PP3V3_G3H

Soji

Member
Board came in dead, drawing just 5V and draws 20V with battery collected only. Checked for PP3V3_G3H, it was 1V

Checked U7650, pin 23 12V is present
And none of the enable signals were present
 

Soji

Member
1.2V , 1.8V, 3.3V Awake not present
0.8V, 1.1V, 1.8V SLPS2R not present
5V, 3V3, 1.8V G3S voltage not present
0.9V, 1.8V SSD not present
 

2informaticos

Administrator
Staff member
Machine cannot enter DFU without AWAKE and SLPS2R voltages.
You may have a problem with U7800.
Check PMIC LDOs in page 71.
Be sure R7900 is good.
 

Soji

Member
R7900 is good, PP3V3_G3H_RTC is 3.3V
pp3v3_g3h_pmu_vddmain is 1v
pp3v3_g3h is 1V
1v8_SLPS2R
1v1_SLPS2R
 

Soji

Member
1V1_SLPS2R not present
1V8_SLPS2R not present
PP3V3_S5 not present
PP3V3_AWAKE not present
0V8_SLPS2R not present
1V2_SLPS2R not present
PMU_LDO3_OUT_R
 

2informaticos

Administrator
Staff member
Are you sure R7900 is good?
Check voltage on pin 2.

If OK, then change U7800.
First be sure no short on its LDOs...
 

Soji

Member
Yeah R7900 is a 0ohm resistor and it has a 3.3V on both sides, checked all LDO's resistance using diode mode, there was no short.
Pls what's the meaning of LDO....
 
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