Working on an 820-3437 board with no power. Green/orange LED, but no fan spin. CPU does not get warm.
PPBUS, 3v42, vrtc, 5v_s5, 3v_s5 all stable and present. Where things get funky is with the higher-up voltages--pp5v_s0, pp3v3_s0, 3v3_s3, vcore, and p5vs4rs3_en--are all pulsing. They come up for a split second, then disappear. VCORE is present, but pulses along with the other voltages. I tracked back the pulsing, and R8177/R8179 are both pulsing on both pins (s4_pwr_en, pm_slp_s4_l).
I checked for a short on the s5/s4/s3 rails and found none. No liquid to the board that I can find. Inspected very closely under the microscope.
Any ideas where I should go next? All help appreciated!
PPBUS, 3v42, vrtc, 5v_s5, 3v_s5 all stable and present. Where things get funky is with the higher-up voltages--pp5v_s0, pp3v3_s0, 3v3_s3, vcore, and p5vs4rs3_en--are all pulsing. They come up for a split second, then disappear. VCORE is present, but pulses along with the other voltages. I tracked back the pulsing, and R8177/R8179 are both pulsing on both pins (s4_pwr_en, pm_slp_s4_l).
I checked for a short on the s5/s4/s3 rails and found none. No liquid to the board that I can find. Inspected very closely under the microscope.
Any ideas where I should go next? All help appreciated!