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820-2533 Liquid Damage Green Light No Power

H

Hellfiya

Member
Some liquid damage, a weird symptom is that hard drive powers up but no fan spin(except a small twitch when power is removed), does not recognize or charge the battery.

Liquid damage on R7120(ppbus_cpu_imvp_isns; 12.6v present) and gnd_impv6_sgnd. Also some corrosion at f4260/r4261(fw).

Here are voltages:
ppbus_g3h: 12.56v

ppbus_cpu_imvp_isns: 12.59v(corrosion)

pp3v42_g3h: 3.401v

ppdcin_s5: 16.74v(no batt)

pp5v_s3: 5.05 v
_s0: 0v

pp1v05_s5: 1.056v
_s0: 1.054v

pp1v5_s3: 1.497v
_s0: 0v (.039v diode mode)

pp3v3_s5: 3.3 v
_s3: 3.288v

ppvcore: 0v

pp1v05_fw: 1.05v
fw_ss: 3.208v

smc_on_off_l short does not turn on the machine. Using a genuine 85w charger
 
2informaticos

2informaticos

Administrator
Staff member
Try first to start in SMC bypass mode.

I saw you get some S3 voltages.
That is possible only after power button is pressed; valid for MCP platform.
PM_SLP_S4_L must be high to get S3 voltages.
Check if all are present.
Also check if PM_SLP_S3_L goes high, or pulse at least.
If high, S0 voltages should appear too...
 
H

Hellfiya

Member
I believe I took the measurements after shorting smc_onoff, where there s3 voltages were missing before. When installed in the housing, pressing the power button turns on the hard drive but no fan spin, display or chime, pm_slp_s4 goes high and fluctuates between 0 and 3.274 every couple of seconds. With smc bypass, I get hard drive spin and fan spin(5v_s0 works, and 1v5_s0 appears), but no display or chime, and pm_slp_s4 stays at 3.274, vcore still at 0v
 
H

Hellfiya

Member
All resistors read normally on page 44/45
Page 44:
cpu and mcp voltage sense/filter have 0v
pbus voltage sense enable read normal

while checking voltages I noticed mosfet q7055 (7137) was broken with open line between ppvbat_g3h_charger and ppvbat_connect. I replaced it with a good one and it blew again. Does this point to a bad u7000?
 
2informaticos

2informaticos

Administrator
Staff member
You've got correct PPBUS_G3H and even some S3 voltages.
So U7000 is good; at ?east it was!

You did something wrong when replace Q7055.
Board should work without it; not charging battery, of course.

If you cannot get VCORE on SMC bypass mode, probably dead MCP.
Nothing strange for the years it has...
 
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