820-3462-A - super slow - 300-600% High CPU usage on Kernal Task

[Alan.L]

the board was liquid damaged, corrosion on the SMC area, thunderbolt area and i/o board flex cable. reflowed SMC and replaced any corroded ic.
i/o board flex cable has been replaced.

after that board can turn on. passed ASD 100% no sensor error. but activity showing 300-600% CPU usage on Kernal Task.

is it SMC, thunderbolt or SD card i/o board at fault??

 

[Gmorb]

is everything connected to the board? keyboard/trackpad/battery/flex cables? battery being detected and charging?

 

[dukefawks]

Run ASD, sensor fault likely.

 

[Alan.L]

ASD EFI 100% passed. Everything is connected. Charging and running the battery is fine.

I will try ASD OSX...


***edit***

in ASD OSX show two failed Thermal Interface.

​

 

[dukefawks]

Could still be crap under SMC or bad SMC. Also check all INA2** current sense chips for corroded pins as sometimes ASD will not pick that up.

 

[Alan.L]

replaced SMC and still have the same problem.

then replaced U5400, U5410 and UD240. made no difference.

i have no idea ;(

however, Windows 10 is fast even with boot camp drivers.



any way to see which kext driver in OSX causing it?

 

[Alan.L]

someone on other forum says don't believe ASD OSX. it has many bugs etc and has false failures.


can a bad ME region causes this?

i really want to get this board fixed, its an i7 as well.

the board works well on Windows 10, just not OSX nor safe mode.

 

[dukefawks]

Run MRI and see if that turns up anything. ME should be ok if it passes the "chipset" test.

https://drive.google.com/open?id=1ENhq5La9sZ5BWTo0vqaNzAcTOdWWaQAg

 

[Alan.L]

i did swap the battery, old battery was liquid damaged.

charging, running off the battery, reading battery status in osx is good.


R5429 = 300k, good
R5439 = 45.4k, good


can it be ISL?

 

[2informaticos]

Voltage pin15 of ISL6259?
Also post C5422 voltage.

002 at pins 17/18?

 

[Alan.L]

Voltage pin15 of ISL6259?
Also post C5422 voltage.

002 at pins 17/18?

u7000 - pin15 = 3.368v

i assume you mean C7022
pin1 = 16.53

PP3v42_g3h = 3.404v


resistance between 17/18 of U7000 = 7.60 ohms
resistance between 27/28 of U7000 = 20.5 ohms

 

[2informaticos]

"u7000 - pin15 = 3.368v"
Very bad, SMC receives overcurrent information into R7050...

"resistance between 17/18 of U7000 = 7.60 ohms"
Look at schematic and see the correct value.
Check R7050/51/52 and theyr traces; be sure to have good contact with ISL6259.

 

[Alan.L]

"u7000 - pin15 = 3.368v"
Very bad, SMC receives overcurrent information into R7050...

"resistance between 17/18 of U7000 = 7.60 ohms"
Look at schematic and see the correct value.
Check R7050/51/52 and theyr traces; be sure to have good contact with ISL6259.

yeah i am aware, 17/18 should around 3ohms. i'll check properly once i have time. very likely the ISL is bad. i've already replaced SMC when Duke asked me to.

 

[dukefawks]

How can the ISL cause a high reading between pins 17/18?

 

[Alan.L]

pin2 of R7051 did not connect to R7050. fixed with a jumper.

pins 17/18 of ISL now is 3.3 ohms

U7000 pin15 = 4.2v"


i haven't replace the ISL yet.


so the SMC from the donor has gone bad because the ISL has killed it?? Would I need to replace both together?

 

[2informaticos]

Surelly good contact between ISL and R7051/52?
Also check if R7050 has correct value.

 

[Alan.L]

R7050 = 0.5 ohms. - good
isl has good contact between r7051/r7052/r7050