820-02009 - No S2 line

[Palhano]

iMac won't turn on! On the test button, LED 1 lights up and LED 2 blinks.

C7801 was shorted, I replaced it and the problem was solved. But the iMac still won't turn on.

PPBus_aon -16v
PP3v8_aon - 3.8
PP1v8_aon - 1.8

I didn't find any shorts on the secondary lines!

In diode mode, L8120 reads 0.090. But I don't have another board or references to check.

Any suggestions?

 

[Palhano]

I compared the L8120 line on an A2337 board, and it seems to be OK with that measurement.

Something strange happens: when I use isopropyl alcohol on the PMIC, the board powers on. I have the voltage readings for lines S2. LED 2 lights up normally, but LED 3 does not.

After the alcohol dries, the problem returns!

 

[2informaticos]

Which PMU is affected by alcohol trick?

If is MPMU, try replacing L8300; referenced to 820-02016 schematic.

 

[Palhano]

It's the U8100!

Should I swap the L8300 even though I have 3.8L on both sides (without the alcohol option)?