23XX EPROM adapter board
The 23XX adapter board which allows you to convert a standard 28 pin EPROM to 2316, 2332, 2364 sockets.
This will allow you to use 28 pin EPROMs in place of the 24 pin 2316,2332,2364 EPROMs
Note: This only includes the adapter PCB, 74HC138 and sockets, and does not include the EPROM (As shown in the photo, this is for illustration only)
As the 23XX EPROM’s could be produced with active high or active-low select lines the adapter can be configured for either signal.
These old 2332, 2364 and 2364 EPROMS were used in many old retro computers (Commodore, Atari) and the original parts are now nearly impossible to find.
The adapter board uses a 74HC138 decoder and using a combination of the select lines allows you to configure the board for any of these EPROMs using newer EEPROMS or older 28 pins EEPROMS (27C128 / 27C256)
Common configurations:
- 2316 (/CS1 /CS2 CS3) 18: Short 2-3 20: Short 2-3 21: Short 2-3 4: Shorted
- 2332 (/CE1 CE2) A: Shorted 18: Short 1-2 20: Short 2-3 21: Short 2-3 4: Shorted
- 2332 (/CE1 /CE2) A: Shorted 18: Short 1-2 20: Short 2-3 21: Short 2-3 0: Shorted
- 2364 (/CE1) A,C: Shorted 18: Short 1-2 20: Short 2-3 21: Short 1-2 0: Shorted
- 2364 (CE1) A,C: Shorted 18: Short 1-2 20: Short 2-3 21: Short 1-2 2: Shorted
Installation
- Make sure the computer is powered off
- Remove the faulty EPROM you are looking to replace
- Configure the adapter board as above.
- Insert the EPROM into the adapter board with the contents burnt on the EPROM
- Insert the adapter board into the circuit.
I have tested the compatibility of these boards on my Commodore VIC20 and replaced all of the EPROM’s and it works 100%.
The only issue I found is when replacing the EPROM on one of the VIC20 versions (assembly 324003) I needed to remove the ground shield in order to fit the adapter into UD7
Board dimensions:
40mm x 21mm
