phone shows no image but appears to work

Bought a phone off ebay in hopes to repair it, with the description "cracked screen, vibrates when turned on", expecting to just replace the screen. With a replacement screen the phone doesn't display an image but the "talkback" feature is turned on, the phone vibrates when picked up and says the screen is on or off, but other than that shows no sign of life, back of phone doesn't feel warm to the touch.