A2442 820-02098 5v 0ma 12.4v PPBUS no light on magsafe 3

[TBFix]

HI only 5v 0m 12.5v ppbus . spillage around ut360 replaced 3 resistors
PPBUS_AON 12.4v
PP3V8_AON 3.8v
PPVDD_DISP_AWAKESW 0v 0.056v diode mode this should be 0.199 ?.
Not sure what to check next any help appreciated

 

[2informaticos]

Not sure about openboarddata posted values.
Impossible to get 0.199 in diode mode and 68 in ohm scale; 0.056 in diode may be good in fact.

Which secondary voltages do you get on the board?

 

[TBFix]

Just going through the rails now
PP0V81_S1_SRAM is pulsing
PP0V95_S2SW_VDD2L is pulsing
PP1V8_S2SW is pulsing
PP0V575_S1_VDDQ0 is pulsing
PP0V575_S1_VDDQ1 is pulsing
PP0V855_S2SW_VDDCIO is pulsing

 

[2informaticos]

Can you put it into DFU mode?
Force it with external switch method, if needed.
Still pulsing voltages then?

 

[TBFix]

Any link to instructions?

 

[2informaticos]

DFU Mode Restore (Macs) - LogiWiki

We have Apple MacBook and iPhone Diode readings and general fault finding information compiled by the leaders in this area

logi.wiki

 

[TBFix]

Thanks for the info , unfortunately PP1V2_S2 is cycling also.

 

[2informaticos]

PPBUS_AON and 3V8_AON stable?

 

[TBFix]

Yes both stable, PPBUS_AON 12.4v

 

[TBFix]

Going back to PPVDD_DISP_AWAKESW I removed coils L7840, l78a0 (4 coils) at U770 and seems to be on U0600 side so I guess cpu is dead yes?.

 

[2informaticos]

"Not sure about openboarddata posted values.
Impossible to get 0.199 in diode mode and 68 in ohm scale; 0.056 in diode may be good in fact."

Could you put the machine into DFU?

 

[TBFix]

No it wont go into dfu mode Apologies for the delay in replying

 

[2informaticos]

Did you try to force DFU mode?

DFU Mode Restore (Macs) - LogiWiki

We have Apple MacBook and iPhone Diode readings and general fault finding information compiled by the leaders in this area

logi.wiki

 

[TBFix]

Yes, but PP1V2_S2 is cycling.

 

[2informaticos]

Then you may have CPU problem...

 

[TBFix]

Thanks for your time, much appreciated.