King_Corduroy wrote:

Hi all I was wondering is it possible to upgrade the Tandy 1000EX's RAM? I know you can do the same upgrade as you can with the PCjr regarding the 8088 CPU to NECV20 but when I google RAM upgrade I'm not getting anything.

You are confusing expanding RAM with upgrading the CPU. The EX requires a special expansion card with a PLUS-style connector. The expansion card also adds a DMA chip to the system,

No I was simply mentioning you could upgrade the CPU. I figured you would know exactly though Hierophant since you are the local expert on all things tandy. 😜
Ok cool, I had read about the RAM card needed but I was wondering if back in the day someone had come up with a way to add ram the poor mans way as they often did with these systems.

I build a "poor man" ram expansion for my ex, work like a charm.

Very simple design! It require 3 static ram chip of 128kB and a 74HCT138 for address decoding.
The good thing with sram is it don't need the additional DRAM chip (no refesh controller) and keep the breadboard very clean and cheap (just 4 chips, some capacitors and TONS of wire).

Later I added a standard isa slot for xt-ide card, more wire but work well to!

So far I didn't meet a tandy compatible game with DMA mandatory, just one oddity: arkanoid 2 refuse to start with more than 384kB...