Bizarre behaviour after cleaning logic board
So I spilled a fair bit of black coffee on my MBP 13 inch late 2011. Immediately removed power, flipped it upside down, and shut it off. I took the back off and let it dry under a fan. I plugged the power cable back in but all I got was a dim green light on the connector and it wouldn’t turn on. So then I took the logic board out to inspect for any signs of corrosion or any liquid. I didn’t see any corrosion as far as I could tell but I brushed it pretty good with a toothbrush and isopropyl alcohol. I put everything expect the back cover back in place.
Now when I plugged the power cord back in I got a solid green light, the fan spun for a half second, but it wouldn’t turn on.
I reset the SMC, and the keyboard backlight would flash for half a second, the light on the connector would turn amber, but it won’t turn on.
I’ve tried variations of this with the battery connected or removed.
I tried holding down the power button with the connector removed, connecting the cord while holding the power button, and then letting the power button go, and I got a startup chime but it powered off a few seconds later. It was hard to recreate this but when I did it did the same thing. The next time I recreated this I did a PRAM reset, and lo and behold, I got the computer to boot up. This was in some special mode where I think something is bypassed so the CPU runs at a lower clockspeed and the fan spins all the time. I could shut down and power on again multiple times in this mode just by pressing the power button. Once I removed power and tried to turn it on again it wouldn’t turn on. But if I did the power button, connect cord, release button trick then it turned on in the special mode again (without having to do the PRAM reset).
Now here’s where things start getting weird. I can’t remember the exact sequence but I think I removed the power cord, and then the battery for a couple minutes, plugged it back in, and tried to start. Nothing. But when I REMOVE the power cord, the computer starts up in the special mode again. It will only last for three or four seconds and then die unless I plug the power cord in before it dies. For example, the computer is not turned on with no power cord connected. I plug power cord in. Nothing. I remove power cord. Computer boots in special mode. I plug it back in within three seconds and it continues to boot in special mode.
Is this a battery issue? DC bus issue? SMC? I can’t diagnose because I don’t have a multimeter.
What the !&&* is going on at this point. I am thoroughly confused. Any help would be appreciated. I don’t have a multimeter or any soldering experience but I could pick some up and figure it out.