-5F in Chicago and this is how I spend a Sunday night. Legacy EPROM version of the Intel 8048/49 as used in the Korg Polyisx, Trident MkII and so on. I made that programmer from a kit in 1986 and outside something like a DataIO Unisite it was a real hobbyist workhorse. I had not used it in ten years, and the EPROM eraser buzzes like an old electric football game, but an hour of grousing with RealTerm and it is programming parts.
Extra info: this microcontroller is for the “KLM-367A” board in a Korg Polysix, which was notorious for suffering battery corrosion damage when the NiCad battery (eventually) outgassed. I first repaired one of these synthesizers in 1993, which was 12 years after it came on the market. 12 years is a long time for a NiCad battery. These days any Polysix that has not been overhauled is likely to have this problem.
One of the first boards I ever did in Eagle was my replacement board for the KLM-367A, which I still sell on occasion to folks who email asking about it:
Lastly, I did a detailed DIY repair page for the KLM-367A in 1999.