SCOPEWRITER Revisited

I spent a couple of evenings taking another look at the SCOPEWRITER. Followers of my blog will remember that last spring, I declared the SCOPEWRITER project a failure. At that time I put it away, knowing that eventually I would make another attempt at getting it going. Well, I have good news, at this point, I can’t call it a failure, it might even be called a qualified success.

Here is an image of the output, that I was able to create.

Scopewriter

I had to make two changes from where I left off, in order to get this output.

  • After entering characters, I had to disconnect the PS/2 keyboard that I had attached to it. The extra power draw of the PS/2 keyboard was too much for the power supply. As I use one of my PS/2 to ASCII adapters to get input to the SCOPEWRITER, I left the PS/2 adapter attached but unplugged the keyboard from the adapter. So I enter characters using the keyboard, then unplug it from the PS/2 to ASCII adapter. You can still see some 60HZ ripple on the output, but it’s not a showstopper.
  • I had two address lines feeding the 2513 Character generator swapped, causing characters to be displayed wrong. At some point, I’ll find a reaonable price on a TMS2501 and pull the jury rigged 2513, which has caused me so much difficulty during this project.
  • So now I have a working SCOPEWRITER. Come the think about it, this may be the only working SCOPEWRITER in the world. What else will I do with it – well at some point it will make a fun output device for the SCELBI 8H and I may just have to create a web page for it. And one other thing – my point of view is that this is really a SCOPEWRITER, not a reproduction – I used instructions and PCB layout from the original magazine article to create it, just like a hobbyist would have done back in the 1970s.

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