2017-07-30 15:25:52 UTC
I have two Apple IIgs's. One is a ROM 3 that works great.
The other is either a ROM 0 or ROM 1 and when I power it on, I only get a checkerboard pattern on the screen. But it's not a perfect checkerboard. Sort of random but in B/W.
This board only has the one ROM chip and it's labeled "TC531000P-7095".
I've re-seated all of the chips that are in a socket. I've swapped out the CPU with a known, working one. I don't get any beeps either.
My suspicion is the ROM is bad. I get the exact same behavior when I power up the board with no ROM at all.
Any ideas what it could be? I could post pics if needed or any model numbers.