820-01987 Does not power from charger but works on battery

[huzeafa]

Hello guys , have got an 820-01987 that does not power from the charger, but works fine on battery. I only get 5V, and PPBUS is 12.3 with charger connected. I have compared diode mode on the LDO of the CD3217 and all seems good , all basic rails for the CD3217 are present: there’s no corrosion anywhere. I couldn’t find a short either: board is spotless. Please help . Thank you

 

[2informaticos]

Do you get 3V3_G3H_RTC with charger alone?
Tried SMC reset?
Did you check U2890 and its traces/resistors?
You may try to reflash it, with known good dump.

Check ohm resistance over C7020/23.
Post U7000 basic voltages (charger only): P_IN, VDDA/P, AUX_DET, SMC_RST_IN, A/BMON.

On battery mode (no charger), USB devices are recognized in macOS?

Just in case, try DFU mode.

 

[huzeafa]

Thank you, will check and get back to you.

 

[huzeafa]

Just a quick question, I swapped U2890 from a working board just to test it, and I still get 5V however its own U2890 on the other board gets 20V. Does this mean they are interchangeable from the same board? if yes, then why do we have to reprogram it ? or is there a different outcome to be expected from the chip other than the 20V negotiation primarily? Please help me clarify this, so I would learn, thank you.

 

[huzeafa]

I do get 3V3_G3H_RTC in the value of 3.3V with the charger connected

U2890 is good tried on another board, also the surrounding area is very clean

ohm resistance over C7020/23 value is the same with a known good board

USB devices are recognized in macOS? I do not have the client password, but my iPhone charges through the port

The device does not go into DFU mode

CHGR_GATE_Q4=5,7V


CHGR_VDDA=5V
PPVBAT_G3H_CHGR_REG=12.2V
CHGR_CSI_P=5.1V
CHGR_LX2=5.1V
CHGR_BGATE=12.2V
PPDCIN_G3H_CHGR=5.1
CHGR_BOOT2=10V
CHGR_VBAT=0.8
CHGR_BMON=0V
CHGR_CSI_N=5.1V
CHGR_GATE_Q3=0.9
CHGR_VDDP=5.1V
CHGR_AUX_DET=1.2
CHGR_AMON=0.05V
CHGR_COMP=1.59V
CHGR_BOOT1=10V
CHGR_EN_MVR=5.1V
PP1V8_SLPS2R=1.8V
CHGR_RST_IN=0V
CHGR_VDDA=5.1V
12C_PWR_SDA_R2=1.8V
CHGR_GATE_Q1=10.4V
I2C_PWR_SCL_R2=1.8V

 

[2informaticos]

Test for USB activity, not only charging.
May have communication problem over USB-C ports; U2800 is involved there.

You can try changing Q7030/40.

 

[huzeafa]

Could you please help me clarify this


“Just a quick question, I swapped U2890 from a working board just to test it, and I still get 5V however its own U2890 on the other board gets 20V. Does this mean they are interchangeable from the same board? if yes, then why do we have to reprogram it ? or is there a different outcome to be expected from the chip other than the 20V negotiation primarily? Please help me clarify this, so I would learn, thank you.”

 

[2informaticos]

TBT ROM is interchangable, between same model boards.

 

[huzeafa]

Thank you so much. This one has been resolved.

So it turns out D3349 and D3328 were burnt out, which then caused damage to both CD3217, replaced both CD3217 and D3349+D3328, and the 20V was restored.

Once again, thank you for your help.