Mac - No light, no power - However it powers up with SMC_ONOFF_L

Hi everyone.

So one day, after my Mac Pro 13’’ late 2013 traveled in luggage and in a humid area, I tried to turn it on and while attempting to boot, it turned off and did not start again. Light on the charger was green at the time. I tried to reset SMC a couple of times, nothing worked really, and by next morning the charger light was not there anymore either.

After I came back home I got to troubleshooting. I took the board apart, cleaned it with isopropanol and a brush, but no luck. Then I watched a bunch of Louis Rossman videos, took it apart again and started measuring voltages:


PP3v3_S5: 0.16V

PPBUS_G3H: 12.33V


I would have guessed something is wrong with the SMC at this point. However, I found that when I short the SMC_ONOFF_L with a needle, the computer turns on, I get fan spin (on for 8 sec, then off, then on again etc.). Sometimes the charger light comes on too. Then through some monkey-ing around, I connected battery, kb, trackpad and screen and shorted SMC_ONOFF_L and it was able to boot into OSX - though admittedly it froze when it got to the login screen, with the chassis still open..

At this point I do not know what is causing all this trouble, is it the keyboard, the SMC, something else? I would really appreciate any input you guys can give.

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