ZX81/TS1000/TS1500 Cleanup: Part 4 (TS1500 Video Mod 1)
17Having a look at the Timex Sinclair TS1500 ... a ZX81/TS1000 with 16KB of RAM in a ZX Spectrum case.
It only has a modulated output so it needs conversion first. There seems to be at least three different ways of doing this ... ?
I tried this way first ... requires just a 2N3904 transistor. It works ... but the output isn't the best ... lots of jailbars:
https://www.timexsinclair.com/timex-sinclair/ts-1500-composite-video-output/
There is a different method listed here ... so I'll try this next:
http://www.zx81stuff.org.uk/zx81/ts1500_video.html
Or, a third method - a little more complex:
https://www.sinclairzxworld.com/viewtopic.php?t=3771
Regarding using a TI 99/4A keyboard externally ... seems I was right!
https://www.timexsinclair.com/hardware/keyboard/diy-keyboards-for-the-zx81-and-ts-1000/
I may have been mistaken about the TS1500 expansion bus being a little different to the ZX81/TS1000 ... the adaptor I was thinking of was the TS1510 Command Cartridge Player. There's one currently for sale (July 2023) in Portugal with an asking price of US$1000 ... yikes.
https://archive.is/6Hohv
Other ZX81/TS1000/TS1500 videos:
https://www.youtube.com/playlist?list=PL5pwokf56wMLVboogvR4xuENeiSlZQJcW