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Have a liquid damaged 820-01700
No wifi hardware detected within OS, liquid damage around U3730.
Are there some base requirements for the Wifi to be detected, nothing looked like it had gone.
Thanks!
I am getting 2.2 ohms on PPBUS_G3H with all U7410/20/30 off.
I removed them and re-applied individually with no change in ohms.
So currently I have U7210/20 and U7410/20/30 off the board and still have the short.
Have an 820-00850 A1989 13" Pro 4 Thunderbolt Port.
Liquid damage to C7214 only, was totally burned out with burning electrical smell. Shorting to ground for sure.
Getting 5.1v on USB
No liquid to anything else.
Fried CPU?
Cheers
Thank you, I have made a few wrong assumptions. Pin 13 - 14 on U7710 was a mistake.
I will go over the schematics a little more and work out what I need to measure to check if there is something up with U3900.
Are there any technical docs re the T2 logic? I had better get a better...
All voltages on Page 78 concerning U7800 look good.
And it looks as if U7710 is turned on by CPU_VCCEOPIOSENSE_P and CPU_VCCEOPIOSENSE_N so wouldn't expect anything on L7702.
The T2 is involved with everything.. Great!
By the looks of it the T2 Chip/U3900 must be powered on for me to have got it into DFU mode but any of the other chips it interfaces with could then kill it and prevent a boot.
Page 69 Values - These all look fine to me.
PP3V3_G3H_RTC 3.29
PPVBAT_G3H_CONN 12.56 <-> 0.18 Fluctuates between the two (No battery connected)
PMU_ONOFF_L 1.79
PMU_RSLOC_RST_L 3.25
CHGR_RST_IN 0
CHGR_COMP 1.56
UPC_PMU_RESET 0...
Getting the following at U7100
CPUSA_PWM - 4.7v
CPUSA_FCCM - 5.05v
Is this below the threshold for triggering U7270?
Getting my head round the order, am I right in think the below?
U7100 provides CPUSA_PWM CPUSA_FCCM which turn on U7270 which then provides PPVCCSA_S0_CPU
This comes on before...
Don't have a good board to test against.
I am getting 0v on CPUCORE_FCCM
CPUCORE_FCCM - GND 123 in diode mode.
Must have measured CPUCORE_PWM1 - 2.5v twice by mistake.
What should FCCM be?
I am measuring around U7100 and will go over pages 69-70