Recent content by emptymind

Harry's Magic Touch Harry's Magic Touch So, I re-inserted the ROMS. And then I fired her up. And then ... ... For no discernable reason in particular ... It initialised the CPU. TODAY IS A GOOD DAY. :D Whilst it would have been nice to definitively identify a failed part I'm more than...

Thanks Dave, I have corrected my diagram and post above. For kicks I gave it a try on my 901447-10 Character Generator ROM. (Which we kind of established was probably fine.) I read the first 8 addresses with the following results which match the binary file in the link perfectly: :D I...

2532 Reading / Writing 2532 Reading / Writing I think I actually might understand this. Can you guys verify my logic? To Read: 1) Pull E to 0 volts 2) Pull Vpp to 5 volts 3) Specify Address to Read using A11 to A0 (use 0 volts for binary 0s and 5 volts for binary 1s) 4) Read Data from...

The 2114s arrived The 2114s arrived Wow - that was quick ! I ordered 4 of the 2114s so I have spares. These are the chips I ordered: It looks like both the old chips must have been dead because I now get this with either pair of the new chips: The characters are a little different each...

Pictures Pictures OK. Here is my new baby: And the board (with the VRAM removed): And the screen output with or without VRAM:

Hi, this was actually my first computer many years ago! I finally found one for sale but I need help to revive it. At the moment when I turn it on the screen is completely filled with a checkerboard pattern. I reseated all socketed chips and got the same result. I then swapped around the...