If it was working and just died them I would check the clock circuit chips as they are known to go bad. See is the clock 2 is pulsing at U15 P5 and U15 P11

might be bad IC sockets. Its hard to see the contact in that type. Sometimes the wiper in the socket snaps off where it bends. Specially on boards with battery damage. The battery corrosive gas can pool in an IC socket and do hidden damage. I have experienced countless non working bally boards come to life after redoing all the IC sockets. A lot of times when you pry off the socket housing there is a surprise of green and blue corroded socket wipe contacts.

Maybe trace continuity from U9 to U6 chip leg to chip leg on all the address and data pins. Then U6 enable(18 and 21) pins back to wherever they come from.

U10 looks rough like the silver plating is coming off the chip legs. Bad U10 shouldnt stop the led from blinking unless two pins on the top row are connected together from the plating flaking off.