I’m testing a new hardware to take place inside the PC-1500(A).
The schematics is OK, the circuit board is manually routed.
And i’m testing it with some classic DIP components.
This new module will be the TE-1508, a 512KB RAMDrive.
It’s like 25x the maximum user RAM area.
All this memory is organized in 16x32KB pages with a write protect jumper and a CR2032 battery.
It’s in the first half of the ME1 zone and can be disabled by software. (Remember that the IWS video interface uses the same ME1 zone.)
But installing it inside the PC-1500 will be a big job.