The 24U universal 24 pin EPROM replacement kit

What is it

The 24U is a universal replacement solution to replace 2708, 2716 and 2732s EPROMS. This kit is a very small adapter board that can take a cheap and easy to find 28 pin EPROM (27512, 27256, 27128, 2764) and can use it to replace a 2708, 2716 or 2732
Note: the 24U will NOT replace a TMS 2532


I created this kit as I work on a lot of early 80s arcade games, and was getting tired of finding and stocking 2716s and 2732s. They are fairly hard to find without spending a lot of time, they are VERY expensive, and often the ones I received seemed bad as many would not program. I was pushed over the edge when I started working on bunch of boards that used 2708s which many modern programmers will not program. I also got tired of waiting for the EPROMS to erase in an UV light. This adapter board allow me to only buy one type of cheap and easy to find 28 pin EPROM chip and not have to stock so many other types. I personally use a W27C512 EEPROM which can be electrically erased in seconds to avoid the pain of waiting for the normal EPROMS to erase.

What's included and what does it look like

For each order you will receive the parts to make 4 adapter boards which include:
  • 4 x adapter board PCBs
  • 4 x 28 pin solder tab sockets
  • 8 x 12 pin terminal pin strips


Cost: 4 units for $20.00 plus shipping

How does it work

It's very easy, follow these steps in ORDER:
  1. Solder together the header pins into the board.
  2. Solder the socket into the new board
  3. Solder the 2708/2716/2732 solder selection jumpers indicate the type of chip the adapter will be replacing, using the diagram below
  4. Program the replacement 28 pin EPROM in an EPROM programmer (such as the GQ-4X), and program the ROM image to want to replace. There is NO need to "double, triple, or quadruple" the image on the new chip, simply burn the original 2708,2716, or 2732 data file onto the new chip as-is.
  5. Solder the 29 pin EPROM selection jumper to specify whether the new chip is a 2764/27128 or a 27256/27512
  6. Insert the programmed EPROM into the socket
  7. Insert adapter into game board ROM socket!
  8. Play!
Note: if you have a v3 board you will have 2 extra jumpers these should be set be default as shown in this image. Ensure that these jumpers are as shown in the image.

I don't believe that it works, prove it!

Here are pictures of the board replacing EPROM u33 (2708) on a Sega/Gremlin Invinco/Head on 2 CPU board.

How do I buy the 24U

Buy the 24U on Etsy

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