A1278 "OTHER High Side Current Sense (IO0R)"

[hazem3636]

hi there


this mac 820-3115 , soo slow and not booting i start using ASD please check attached photos






i satrt with "Power Sensors: High Side"

i found there is issue @ "OTHER High Side Current Sense (IO0R)"

PP3V3_S0_HS_OTHER_ISNS = 3.3

ISNS_HS_OTHER_N = 12.6
ISNS_HS_OTHER_P = 12.6

HS_OTHER_IOUT = 0
so i removed R5419. and still same issue no short to ground at all clean board and i replaced U5410 with same issue no change

any suggestion

[mon2]

Re: A1278 "OTHER High Side Current Sense (IO0R)"

I believe that you also have a bios fault from the error linked to the ME. Suggest to review the bios. Has it been replaced?

[hazem3636]

Re: A1278 "OTHER High Side Current Sense (IO0R)"

yes sir

i did already sir bios was totally damaged and someone expert here in the forum helped me with bios clean version and replace bios chip


now my issue is Current Sense


u5400 out on pin 6 == 3.2 V , diode in pin 4 & 5 == 2.4 ohm

u5410 out on pin 6 == 0.02 v , diode in pin 4 & 5 == 0 ohm

[hazem3636]

Re: A1278 "OTHER High Side Current Sense (IO0R)"

finallllllllllly

U5400 was cut @ pin 4 to R5400 .

normal out now @ pin 6 == .17 V.

i run ASD once again and showing issue @ VC0C i'll check this issue

[hazem3636]

Re: A1278 "OTHER High Side Current Sense (IO0R)"

Bad bad news

SMC_cpu_vsense = .7 v

Ppvcore_s0_cpu = .7 v

[hazem3636]

Re: A1278 "OTHER High Side Current Sense (IO0R)"

Direct power @ L7510