2018 Pro board with PPBUS at 12.3V (820-00850-A)

sekidata

Member
Working on a dead 820-00850. After removing a shorted capacitor (C7651), I get PPDCIN_G3H at 20V, PPBUS_G3H at 12.3V, and PP3V3_G3H at 3.3V.

I tried a DFU firmware restore which showed an error the very end (“The System cannot be restored on this device.”), presumably because the machine cannot start up.

What can I troubleshoot to show why PPBUS_G3H fails to go to 12.6V?
 

2informaticos

Administrator
Staff member
There is a communication problem between T2 and U7000.

If enters DFU, all AWAKE and SLPS2R voltages should be present.
Check if all SSD voltages are there.
 

sekidata

Member
The following voltages are present for ca. 5 seconds, then go to 0 for 1 second, and pulsing so forth:

PP1V2_AWAKE: 1.2V
PP1V8_AWAKE: 1.8V
PP3V3_AWAKE: 3.3V
PPVDDCPUSRAM_AWAKE: 0.8V
PPVDDCPU_AWAKE: 0.75V
PVDDCPUSRAMAWAKE: 0.8V
P1V1SLPS2R: 1.1V
P1V8SLPS2R: 1.8V
P1V8SLPS2R: 0.8V

The SSD voltages are:

PPBUS_G3H_SSD0: 12.3V
PP3V3_G3H_SSD0: 3.3V
I2C_SSD_SCL: 1.8V
I2C_SSD_SDA: 1.8V
ISNS_SSDNAND_N: 12.3V
ISNS_SSDNAND_P: 12.3V
ISNS_SSDNAND_IOUT: 0.23V
P1V8_LX0_SSD0: 0V
P0V9_LX0_SSD0: 0V
P2V7_SW1_TPS62180_SSD0: 0V
 

2informaticos

Administrator
Staff member
Put some logic on your work.
I said all AWAKE and SLPS2R voltage have been confirmed; as you was able to see the machine in DFU mode!
However, is your choice, if you like to waste time checking them again.

You didn't check exact points expected for SSD voltage; but enough to see all missing.
Check diode mode to ground at L9020/30/80.
 

sekidata

Member
Just noticed that U7000 gets extremely hot as soon as the charger is plugged in... I assume it's shorted. This component (ISL9240) isn't easy to find, so I'll order from China.
 
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