820-3436 no power

[peterfixit]

macbook pro 820-3436 no power, green light no fan spin
visual inspection, dirty, ssd getting warm
rails
ppbus 12.58 pp5vs5 5v pp3v3s5 3.3
pp3v3s4 0.45v 3v3 sus 1.94 3v3s3 0
pp3v3 s4 fet 0.334 pp5vs4 reg 0 P5VS4RS3_EN 0
PM_SLP_S4_L 0 (no i did not rehot cpu bro)
replaced u1950, cpu warm still no sys pwrok

 

[dukefawks]

If CPU and SSD are getting warm then some rails must be powering on. Check voltages on CPU Vcore and other coils.

 

[peterfixit]

PPVCC_S0_CPU is 0 obviously, pp3v3 s0. 1.9v 3v3 sus 3.3 3v3s4 0.444 other coils? the point is im missing pm_slp_s4_L, without this the cpu wont power on

 

[dukefawks]

How is the CPU getting warm then? Some rail to the CPU must be powering it, same goes for the SSD.

 

[peterfixit]

it would be nice if i had some hints, PP3V3_S0SW_SSD 3.3v SSD_RESET_CONN_L 0 ssd_pwr_en 1.725 ssd_clkreq_l 2.781
PP1V05_S0_CPU_VCCST 0 CPU_VCCST_PWRGD 0, cpu is no longer getting warm, so can we go back to the original issue

 

[dukefawks]

PP3V3_S0SW_SSD should not be high. SSD_PWR_EN at 1.7V is very strange as this is pulled up from 3V_S0. ssd_clkreq_l at 2.7V is also weird, signal is also pulled up from 3V_S0. What is the voltage on PP3V3_S0?

Some history on this board may also help as I truly have no idea what is going on here.

 

[peterfixit]

history is strange and sounds like water damage, but isnt. one day working next it was dead. because this one is weird ive posted here before messing with it

pp3v3 s0 1.939

 

[dukefawks]

This is really just a stab in the dark, but check PPVRTC, corrosion around U1950/1900/6100.