820-3209 rails pulsing

[No-Clean]

Clean board, no corrosion.

SMC bypass same problem
Clean BIOS same problem
Reballed SMC same problem

PPBUS_G3H present
PP3V42_G3H present
PP5V_S5 present
PP3V3_S5 present
PP5V_S3 pulsing
PP5V_S0 pulsing
PP3V3_SUS present
PP3V3_S3 pulsing
ALL_SYS_PWRGD pulsing
Resistance between pins 17/18 and 27/28 of the ISL6259 are correct
R7021, R7022, R7051 and R7052 are all fine

Any help will be greatly appreciated!

 

[No-Clean]

Hi @2informaticos please let me know if you can help, thanks!

 

[2informaticos]

Pulsing every 5s, or just two times?

Clean board, still should have an history fault.

All secondary voltages pulsing?
Check at all coils, as pages 60 & 61 too.

 

[No-Clean]

Pulses every 5 seconds non stop.
Customer tried to use the mac and it just stopped working.

All coils are fine, power fets pulse in the power and enable signals, looked for shorts on all power rails and nothing.

 

[2informaticos]

Pins 2 & 4 of U2760 pulsing?
What about PLT_RESET_L?