ZX81/TS1000/TS1500 Cleanup: Part 1
30I've been collecting bits & pieces over the years and have done some experiments to try to find the best overall improvements that could be made.
But ... surprise ... things have been left half-done, so it's about time I sorted out what I've got and fix up what I can.
I've got mostly Timex Sinclair TS1000s as these are quite plentiful and relatively cheap compared to ZX81s. I've also got a TS1500 which is a ZX81 (or TS1000) with 16KB of RAM in a ZX Spectrum case ... actually, I might have two ... just remembered a briefcase version ...
The main things I like to do:
[1] Convert TV modulator to composite (emitter follower)
[2] Replace the 7805 linear regulator with a modern switching equivalent
[3] Replace ULA with vLA81
[4] Upgrade RAM from 1KB (or 2KB in TS1000) to 16KB
[5] Replace the original 2364 with something else
[6] Replace the keyboard membrane if required
Replacement 2364 ROM:
https://store.go4retro.com/rom-el-2364-flash-rom-replacement/
https://github.com/Toysoft/ZX-81-ROMS
https://k1.spdns.de/Vintage/Sinclair/80/Sinclair%20ZX81/ROMs/
ZX-Key external keyboard:
https://www.zx81keyboardadventure.com/
vLA81 ... excellent replacement ULA:
https://www.vretrodesign.com
ZXpand+ joystick & SD interface:
https://www.sellmyretro.com/offer/details/63279
Other ZX81/TS1000/TS1500 videos:
https://www.youtube.com/playlist?list=PL5pwokf56wMLVboogvR4xuENeiSlZQJcW