Apple II

Hello all:

New member here.  I FINALLY own an Apple IIe.  When I was a kid back in the early 1980's I always wanted an Apple II but it wasn't in the family budget.  After almost 36 years I finally own one.  I became a vintage computer collector several years back as it fuels my nostalgia or the early days when I learned to code and hack.  The unit I bought on eBay does not have a mouse and the M0100 mice on eBay are way over priced.  So I am setting out to build my own adapter to use a PS2 mouse on an Apple IIe.

So the Apple IIc (at least, the one I have) has a thin gray membrane of sorts that overlays the keystems.  It's badly cracked and deteriorated.  My intuition is that it serves no immediately valuable purpose and can probably just be disposed of.  Though I'd ask just in case there's a reason to keep it or try to replace it.

I get "RAM 00100000" on my screen when I hold both Apple keys down during boot.  I can remove all cards and get the same thing.  I have replaced the 3rd of 8 RAM chips, after desoldering suspect RAM and soldered in a socket before putting new RAM in.  The 4th and 5th chips are also socketed and I tried swapping those as well.  I can enter and run a BASIC program, but booting from floppy doesn't work.  Help!

I recently rescued an Apple IIe, Monitor II and Disk II from the e-waste pile. Unfortunately, whoever left them had cut all of the cables off the back (including the power cable on the monitor). There was a ribbon cable between the IIe and Disk II. Are there any easily-available replacements for this, or will I need to look into building one?