spontaneous no power failure, mid 2012 retina

[Rylyon]

To start off, this was a previously water damaged computer. When I got it it turned on and worked fine, but I disassembled it and cleaned the mobo anyway, there was only one spot with noticeable corrosion, and the entire backside of the mobo was clean.

It's been working flawlessly for 6 months. Today I closed the lid and left it unplugged for a few hours. When I tried to wake it there was no response. I took it home, plugged it in still no response to power. I reset Smc, the magsafe light flashed green, still no response. I have also tried reseating the keyboard ribbon cable and shorted the power pads with ribbon cable in and out. Nothing.

The only other weird thing is that the magsafe light is still orange but it's been plugged in for hours. Any ideas to try would be helpful.

 

[duervo]

Liquid gets in between the chips and pcb. No amount of "cleaningi", short of a proper bath in an ultrasonic cleaner, is going to get rid of any corrosion that will happen there.

 

[Dadioh]

To start off, this was a previously water damaged computer. When I got it it turned on and worked fine, but I disassembled it and cleaned the mobo anyway, there was only one spot with noticeable corrosion, and the entire backside of the mobo was clean.

It's been working flawlessly for 6 months. Today I closed the lid and left it unplugged for a few hours. When I tried to wake it there was no response. I took it home, plugged it in still no response to power. I reset Smc, the magsafe light flashed green, still no response. I have also tried reseating the keyboard ribbon cable and shorted the power pads with ribbon cable in and out. Nothing.

The only other weird thing is that the magsafe light is still orange but it's been plugged in for hours. Any ideas to try would be helpful.

See if bypassing the SMC works. On the left side of the keyboard hold down the following 3 keys: shift, ctl, option. While holding those keys press and hold the power button. Keep holding everything down for a few seconds and then release the three keyboard keys but keep holding the power button. Hold power button about 5 seconds and then release. Then briefly press and release power button again. If it works, fans will go to high speed and it will boot.

 

[Potatochobit]

how is the battery i wonder?
is it possible to turn on a mac without a battery inside?

 

[maflynn]

how is the battery i wonder?
is it possible to turn on a mac without a battery inside?

If its a retina MBP the battery is sealed AFAIK.

Its possible that the water damage the OP is mentioning may have corroded something