Does not turn on but blinks

Just replaced screen which was pretty simple via YouTube clip. Double checked connections. Worked fine then after about 20 min it powered off. Now power light only blinks. Haven't used a battery for over a year because it's no good only used power cord. I tested the cord with a flusk 36 meter works fine at 19.4 volts. Tested inside connector from board to power...works fine 19.4...still blinking. Any help would be greatly appreciated...thks.

PS....laptop had not been used in over 9 months.