This is part of a series of posts for the Retro Challenge 2018/04.  See my index page for the other posts.

So April comes to a close, and with it the April 2018 Retro Challenge.

I’ve spent the month of so buried in these Osborne 1 computers, and have achieved a great deal in restoring them to their former glory.

All the details are in the last 17 blog posts, but I’ve also made a 36 min video summarising everything I did (along with a slightly closer look at the computers and some demos):

So to wrap-up the Retro Challenge, let’s look at what my goals were, and whether I met them:

• Refurbish the second Osborne 1 (re-cap the PSU, service the disk drives) and get it booting
  ✓ done – I also needed to recalibrate the monitor
  
• Try to make new boot disks for the first Osborne 1 and get it booting.  I can then hopefully pass it on to another collector.
  ✓ I did manage to make new boot disks, and I did verify that the PSU, monitor, keyboard, disk drives, CPU, video board, and disk controller were all working.
  ✘ It still fails to read disks (with sector errors) but I have narrowed down the problem to the motherboard.  My suspicions are the PIA (interfacing the disk controller to the CPU), or the logic chips between the disk drives and the disk controller, or possibly a RAM chip buffering the data from the disk controller.  I need to investigate more, but I need to acquire/borrow an oscilloscope or logic analyser to make further progress.
• Find a way to get internet-downloaded software onto the Osborne (possibly using a USB floppy drive emulator, possibly using the serial port).
  ✓ ✓ both serial and USB transfers done, along with a semi-permanent USB drive installed in a storage pocket in the Osborne
• Conclude by playing a classic CPM game on my portable computer!  Preferably Colossal Cave Adventure or The Hitch-Hiker’s Guide to the Galaxy :-)
  ✓ ✓ both done :-)

All-in-all I’m very happy with my progress, and extremely happy with my restored machine :-)

I’m sure there will be more posts to come as I do more with my Osborne (and try to fix the broken one) but they’ll be much more occasional from now on!