Macbook Pro 2011 seems dead.

I just bought a defective Macbook Pro 2011 in hopes of repairing it. The laptop does not turn on, the light on the MagSafe adaptor is not turning on, no matter what I do. I tried a SMC reset. The only life I see, is the battery indicator blinking when the laptop is plugged in. I tried removing the battery and plugging it back it, however still nothing. The seller assured me that no liquid had been spilled on the laptop, so I thought it was a fairly easy SMC reset needed, however I stand corrected. The seller also said that the laptop just stopped charging, and was slowly discharging until it died, and has not been able to charge afterwards, this does not sound like the mainboard has fried, does it? I have not tried another Magsafe adaptor, however I measured this one to be outputting about 18V. Also, the little battery indicator is blinking on the laptop, when the adaptor is plugged in, and the small check button is pressed, so I am guessing the DC board and Magsafe adaptor is working okay. I made a small video describing the problem:

I hope I can get some life back in it, else I'll have to sell is as completely dead.

Regards

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