Toshiba Satellite L655D won't boot

Jan 1, 2019
With battery in and power supply plugged in I see power light and battery charge lights on. When I hit the power button the Numlock and Capslock lights blink once and the power on light lights up. Nothing comes up on the screen. Same response when hooked up to an external monitor. Breaking open the case I've unplugged various components to eliminate them from the equation with no effect. Any suggestions appreciated. Thx - Bill