[SOLVED]Macbook Air (820-3437-B) Power issue on PP3V3_S0 or something else :-))

[Ciki]

Now board has the liquid damaged ,first when I get it have green ,orange on charger and start fan very loud ,no chime ,then I found that PP3v3_s0 missing ,on PPVCC_S0_cpu was only 0.054V, first thing was to remove U8030 ,try put the new one nothing no power ,no fan spin ,try soldered u8030 few times I was guessing bad connection because i had pp3v3_s5 and p3v3s0_en ,now will start only if I remove U8030 with same symptoms from beginning very loud fan and no brain ,so if I put back U8030 nothing ,dead ,and I measure in diode mode pp3v3_s0 and its not shorted

 

[dukefawks]

That is normal, I bet the power cycle works normal and the whole board is power cycling. Check all rails for shorts. Then check all the usual corrosion points, U1900, U1950, U6100 and termination resistors and traces to U6100, J6100.

 

[Ciki]

Try everything new u8030 ,re-soldered u1900 and u1950 dont see any corrosion ,put 3v on pp3v3_s0 cant found any hot component,still without U8030 fan spin ,loosing mind

 

[dukefawks]

Is the board power cycling?

 

[Ciki]

The board without u8030 turn on ,fan spin but have only 0.54v on cpu vcore, when put back u8030 no spin missing pm_slp_s4 ,how you mean power cycling,when turn stay on ,no restarting or cycling

 

[dukefawks]

U8030 needs to be on there. Power cycling will be very short pulses on all rails. Best to measure with a scope as many multimeter will be too slow to catch the pulses especially auto ranging ones.

 

[Ciki]

I remove bios chip and check pp3v3_s0 and its cycling freom 0.05 to 2.5 v ,what should i look

 

[dukefawks]

All the stuff I already told you. U1950, U6100 and traces to it and the termination resistors (16 of them).

 

[Ciki]

Sorry termination resistors on which rail ?

 

[dukefawks]

Search schematic for "termination" They go from data lines of U6100 to CPU and SMC. Traces or resistors are suspect.

 

[Ciki]

Hi man finally working ,the problem was Jtag connector thx