I have 2 Apple IIe motherboard and a power supply
when I power the first board, the screen is cleaned and then the simple word "Ram:" is written on the top left corner...
nothing else. I deduced (I may be wrong) that the board is working but lack peripherals and specially a keyboard
(if I remove the 74LS154 decoding the IO I get "Apple II and a prompt"
on the second board, the screen is filled with little colored squares (I guess it's just low resolution) an nothing else.
if I put the rom of the previous board to this one, I columns on screen patterns containing '*'
apparently on of the set of eprom is enhanced the other set standard
any idea to what I should look to solve the problem of the board with the screen filled with colored squares ?
I try to swap many parts without real success...
any idea ?