Initial assessment

The PC came to life right after putting in batteries and turning it on. I guess there is a lot to learn about how to use that thing - luckily, finding the manual online is not that hard. 

The docking station didn't show any sign of life initially. It had been opened by the previous owner in an attempt to fix it, and some cables were hanging out, presumably to bypass the battery. I removed the dead NI/CD batteries which (surprising, after 40 years) had not leaked too badly and after some poking around with my multimeter, I found a very much hidden broken trace that prevented the thing from powering on. After fixing that, and closing it up again, the print unit failed because its wires were corroded and fell off the circuit board. I replaced the wires, and now the dock works fine. All that can be seen in this video:

Making new pens for the plotting unit

Now that PC and dock were running, I wanted to print something. Unsurprisingly, the pens that were in the drum unit since 40 years were dried out. Instead of buying new pens (every now and then they are available for moon-prices) I developed my own method to get new ink into the pens and replace the writing tip with the business-end of a Stabilo Point 88 fine liner tips. My method is described in detail here:

Coding something cool :)

The Sharp-PC can receive (and send) BASIC-code and data via audio-cable. After setting up "Pocket tools" (http://www.pc1500.com/pc-pocket-transfer.html), a toolkit written by some retro-enthusiasts for converting text into the audio-format that the Sharp-system needs, I was able to create my own code, send it to the machine and run it.

I had not done BASIC since my childhood, where I preferred Qbasic (and soon after, Pascal) over playing DOOM or Quake. Not having any structural elements such as functions or bracket-hierarchies took some getting used to again after decades of C, python and the like but I quickly adapted to using line numbers, GOTO and GOSUB. All my code can be found on github:

https://github.com/joekutz/Sharp-PC-1500-BASIC

I wrote a little Demo that paints some houses and clouds, and because I am a data-analyst by profession, I coded the K-Means clustering algorithm, made it sort some points for me and print out the result using the four colors. All that can be seen here: