Tandy 1000 EX/HX RAM Expansion Board by Adrian Black. Cheap and simple, only requires 4 IC's (3 if you choose to bypass the 74LS245 with jumper links.)

You can leave off the LED and R3 if you don't want the LED. This is tested in both the Tandy 1000 EX and HX machines. If you use 74HCT logic, you can substitute 10k resistors for R1 and R2.

See the video about the board at: https://www.youtube.com/watch?v=l3RWOZX58A8

Uploaded files here are version 1.2 of the design with the fixes applied that I talked about on the video.

Notes: Created in KiCad v5.1.4-1