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820-00281 a1707 misbehaving. Strange DCIN and other pulsing rails
- Thread starter ALB-Repairs
- Start date
When you get it working, does it recognize the battery?
Does it always start in SMC bypass mode?
Check exact value for R7021/22 and R7061/62.
Post voltage for SMC_DCIN_ISENSE and SMC_BMON_ISENSE when MLB doesn't start.
Does it always start in SMC bypass mode?
Check exact value for R7021/22 and R7061/62.
Post voltage for SMC_DCIN_ISENSE and SMC_BMON_ISENSE when MLB doesn't start.
ALB-Repairs
Member
Nope, liquid was very localised to R4911 and the surrounding area, and extremely minor. You can only tell its ever been damaged if you really look hard for it.
ALB-Repairs
Member
When it is running it is recognising and charging the battery.
It does starts normally (not in SMC bypass). Since the original repair i have removed my wire from debug power button and replaced r4911 wiring it to the correct net, so this board can now be treated as unmodified.
I will check exact value of the resistors, and the voltages tomorrow when i am back in work.
Thanks
ALB-Repairs
Member
R7021/22 and R7061/62 All measure perfectly (1ohm) each
I have been able to get it into its failure mode. When this happens all power rails other than CPU-Vcore pulse. I belive it is caused by some USB C charging issue maybe. This is because in its failure state DCIN seems to be wrong (pulsing 1.7V at r7020). If i reseat the charger it seems to start working again.
SMC_BMON_ISENSE remains 0V (batt plugged in)
SMC_DCIN_ISENSE pulses to around 0.3V.
Thanks
I have been able to get it into its failure mode. When this happens all power rails other than CPU-Vcore pulse. I belive it is caused by some USB C charging issue maybe. This is because in its failure state DCIN seems to be wrong (pulsing 1.7V at r7020). If i reseat the charger it seems to start working again.
SMC_BMON_ISENSE remains 0V (batt plugged in)
SMC_DCIN_ISENSE pulses to around 0.3V.
Thanks
Last edited:
ALB-Repairs
Member
Replaced all 4 CD3215's with no improvement.
I am confused because something is causing the CD3215's to not communicate with the charger during its failed state.
Because PP3V3_G3H is not pulsing it leads me to believe a GPIO pin is causing the DCIN Rail to pulse.
Does anyone know of all the requirements for the DCIN rail to come high?. As i understand the CD3215's need to be present and communicate with there ROM chip via i2c, PP3v3_G3H is needed to power the CD3125's, PP3V3_UPC_TA_LDO is required from CD3215 to power the ROM chip. CC1 and CC2 select voltage from the charger.ect
I am really confused by the DCIN rail pulsing, maybe a Reset signal is pulsing causing this?
Any help would be awesome.
I am confused because something is causing the CD3215's to not communicate with the charger during its failed state.
Because PP3V3_G3H is not pulsing it leads me to believe a GPIO pin is causing the DCIN Rail to pulse.
Does anyone know of all the requirements for the DCIN rail to come high?. As i understand the CD3215's need to be present and communicate with there ROM chip via i2c, PP3v3_G3H is needed to power the CD3125's, PP3V3_UPC_TA_LDO is required from CD3215 to power the ROM chip. CC1 and CC2 select voltage from the charger.ect
I am really confused by the DCIN rail pulsing, maybe a Reset signal is pulsing causing this?
Any help would be awesome.