PCB Fetzner 64K/128K ROM cartridge board (bare)
Product Details
128k ROM (512kb) TI-99/4a cartridge PCB
These boards are 128K while being fully 64K Guidry board compatible. The 128K just uses the last unused latch from the 64K boards. You can also add two SPST switches and a pair of 2.2K resistors to make them switchable to 512K (in the form of four separate 128K banking zones).
Assembly required, parts list:
- 28-pin or 32pin .600 Socket
- 74LS379 Logic chip
- 68 ohm resistor
- 22pf capacitor
- 1nf capacitor
- Six 0.254mm jumper terminal headers
- Up to five 0.254mm jumpers
- A 27(C)64 (8K), 27(C)128 (16K), 27(C)256 (32K), or 27(C)512 (64K) EPROM