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A2141 820-01700-A no power

H

hgoncalves

Active member
Hi,

I have an A2141 820-01700-A with no power. It is cycling in between 0V to 5V continuously on all 4 usb-c ports (ampmeter powers on and off).

It has no signs of corrosion nither liquid contact, and client says that it just stoped working.

UB300 diode reading:
USBC_TA_CC1 = 0.590
USBC_TA_CC2 = 0.588
PP3V3_UPC_TA_LDO = 0.467

UB400 diode reading
USBC_TB_CC1 = 0.586
USBC_TB_CC2 = 0.585
PP3V3_UPC_TB_LDO = 0.478

U3200 diode reading:
USBC_XB_CC1 = 0.586
USBC_XB_CC2 = 0.586
PP3V3_UPC_XB_LDO= 0.468

U3100 diode reading:
USBC_XA_CC1 = 0.587
USBC_XA_CC2 = 0.586
PP3V3_UPC_XA_LDO = 0.475

PPDCIN_G3H has 0.545 on diode reading
PPBUS_G3H has 0.382 dioed reading
PP5V_G3S has 0.397 on diode reading

PP1V8_G3S has 0.006 on diode reading and 3.7 ohm to ground (seams to be shorted). Can I inject 1V here?

Can you help?
 
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2informaticos

2informaticos

Administrator
Staff member
You can inject even 2V, but may need a thermal cam to detect snall temperature differences.
Remove CPU heatsink first...
 
H

hgoncalves

Active member
Hi,

U8220 seams to be the only component that gets hot but even after removing it, the short remains, and PP3V3_G3H_T seams to also be shorted (0.003 in diode reading). U7800 also gets hot when injecting 2V on PP3V3_G3H_T.

I don't have a same model donor board.

Can I use the same components from a different model board?
 
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H

hgoncalves

Active member
Hi,

Can you help with the board model. I can't find those components on otehr schematics. Do you know any other model?
 
2informaticos

2informaticos

Administrator
Staff member
Look at "Power FETs" page in other schematics.
You may find chips with different name, but same function.
 
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H

hgoncalves

Active member
Hi,

PP1V8_G3S now has 0.250 in diode reading, but 0V. The power isen't cycling anymore, but it 's still at 5.12V and 0.26A
 
H

hgoncalves

Active member
Hi,

No it isen´t recognized in DFU. However, I notice that with the battery conected it pulls 20.5V and 0A from ampmeter, on all USB ports, and without battery connected only 5.12V and 0.26A
 
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H

hgoncalves

Active member
P1V1SLPS2R_FB is cycling in between 0V and 0.080V
P1V1SLPS2R_SW0 is cycling in between 0V and 0.080V
P1V1SLPS2R_SW1 is cycling in between 0V and 0.080V
PP0V8_SLPS2R = 0V
P1V8_SLPS2RSW_DFR_R = 0V
PP1V2_AWAKE_SOC_PCIEPLL_F = 0V

U7800 seams to have a small spot on it that might be burnt signal.

Shall I replace U7800?
 
H

hgoncalves

Active member
I can't find R7835. Only C7835. Are you sure?

All coils have low diode reading:

Diode reading Good board:
L7813 = 0.349
L7817 = 0.050
L7816 = 0.050
L7814 = 0.278
L7815 = 0.278
L7806 = 0.010
L7807 = 0.010
L7808 = 0.010
L7809 = 0.010
L7811 = 0.037
L7812 = 0.037
L7810 = 0.327

R7814 = 0.279

Diode reading bad board:
L7813 = 0.016
L7817 = 0.012
L7816 = 0.012
L7814 = 0.002
L7815 = 0.002
L7806 = 0.021
L7807 = 0.021
L7808 = 0.021
L7809 = 0.021
L7811 = 0.048
L7812 = 0.048
L7810 = 0.383

R7814 = 0.002
 
H

hgoncalves

Active member
R7900 seams to be ok and has 0 ohm resistance.

After replacing U7800 all the doils diode readings are likely the same.

After close inspection, I notice that U8250 seams to be a bit blown and is geting a bit hot on thermal cam. I don't have a donor board to it. Do you know other board model that I can use as a donor for U8250?
 
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