Hi there folks, I'm new to the wonderful world of the Apple II and recently came across an offer that was too good to pass up for an Apple IIc, ROM 255. Anyway, to get to the point, the initial problem I had with the machine was some strange zeroes showing up on bootup, and disks either continually spinning and not loading, or with some ProDOS based programs, a message that would come up with "COULD NOT LOAD PRODOS" or something to that effect.
After doing a little research, I came across this page showing pretty much the same problem I was having. So, following his instructions (and also because I didn't have an updated ROM 0 or higher with the built in RAM diagnostics), I proceeded to do his "piggyback" method to do sort of a process of elimination to find the bad RAM. When I got to ARD4, the zeroes went away!
I thought I had found the offending RAM chip. So, with the RAM chip still piggybacked, I went and tried to launch a disk. Good news was that disks were actually being read now. The drive would go through the motions and attempt to read the disks. The bad news was that the programs would usually crash out almost immediately after starting with what looked to be some weird kind of hex code or something:
I figured this was because I would need to remove the offending RAM chip and replace it with the one that I piggybacked on it to get rid of the zeroes and get the drive to wake up again. So, because I am a complete electonics novice as far as de-soldering and removing chips, as well as soldering in new chips, I enlisted the aid of my father who has a pretty extensive background in soldering. Anyway, he came over, removed what I believed to be the bad chip, and he soldered in the new one. Well, this is what we see now:
This is all we see on bootup (actually it varies, it's either this, or various other glitchy looking screens, sometimes with graphics, sometimes with characters). No bootup "beep" sound, no drive activity, nothing. We tried two different 4262 chips with the same results. I have six more chips, but I'm not sure they'd do any good. Even tried leaving the socket open without a chip and got the same results. I've tried doing some more research and now I'm at a loss. I was hoping to come to this forum and maybe find someone with similar issues, and if so, how they repaired them. I'm hoping my dad didn't pooch anything accidentally while he was working on the board, but I have no idea.