This repository contains the KiCad project and Gerber files for an adapter that allows to replace 2332 and 2364 ROMs with 2764, 27128, 27256 or 27512 EPROMs.
Warning
This adapter is currently only used for replacing 2364 ROMs. Replacing 2332 ROMs is untested! Use at your own risk!
The subdirectory "gerber-files" contains a Zip file you can use to order the PCB from PCB manufacturers like PCBWay or JLCPCB. Simply upload the Zip on their web page. I recommend to order the standard PCB thickness of 1.6mm and HASL finishing.
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2x 1x12 Pin Straight Male Precision Header 2.54mm pitch.
Used to connect the adapter with the socket of the ROM. Make sure that you use precision headers (round/machined pins) and not standard square pin headers, because these will wear off the socket!
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1x DIP28 Precision Socket 2.54mm pitch 15.24mm width.
Used to connect the EPROM to the adapter. I recommend to use a precision socket, because standard sockets with double spring contacts collide with the pin headers. When you use standard sockets, you have to cut the pin headers.
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3x (when replacing a 2364) or 4x (when replacing a 2332) 10kOhm SMD Resistors 0805 size.
These are pull-up resistors for the address lines A13 (R2), A14 (R3) and A15 (R4). When replacing a 2332, you need another pull-up resistor on address line A12 (R1).
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3x (when replacing a 2364) or 4x (when replacing a 2332) 1x2 Pin Header 2.54mm pitch.
These are used to externally switch the address lines A13, A14, and A15. When replacing a 2332, you need another pin header for address line A12. You may use straight or angled pin headers, depending on the space available around the adapter. When using straight pins, you need space above the adapter, and when using angled, you need space to the side of the adapter.
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3x (when replacing a 2364) or 4x (when replacing a 2332) Jumper 2.54mm pitch.
These are used to externally switch the address lines A13, A14, and A15. When replacing a 2332, you need another jumper for address line A12. These jumpers can also replaced by switches or a microcontroller, this depends on how you want to switch the contents of the EPROM.
You have to start with soldering the resistors on the top of the PCB, because they are located under the socket. These are the only SMD parts and quite fiddly to solder by hand. When replacing a 2332 ROM, you have to populate all four resistors R1, R2, R3 and R4. When replacing a 2364 ROM, you only have to populate the three resistors R2, R3 and R4, R1 must not be populated!
When replacing a 2332 ROM, you have to cut the jumper JP1 on the bottom of the PCB. Be careful and use a sharp cutter knife, and check with a multimeter that there is no continuity! When replacing a 2364 ROM, you have to leave JP1 connected as it is.
Now, solder the two 12 pins precision pin headers to the PCB. As I said above, please use precision (round/machined) pin headers instead of the standard square pin headers, even though they are quite expensive, otherwise you will wear off the socket. The round pin headers will also wear off the socket, but much less than the standard pin headers.
Be careful to use the correct location on the bottom side of the PCB - use the two shorter rows of 12 holes marked with rectangles on the silk screen!
It is crucial that you solder these pins straight to the PCB, otherwise they will not fit into the socket later. I used an old breadboard as a soldering aid, but it sucks away a lot of heat, and you will need to apply a lot of heat when soldering. Be careful not to drop any solder onto the breadboard!
Solder the socket to the top of the PCB. Mind the orientation, the notch of the socket should face in the direction marked on the silk screen (to the right in the image below). When you do not use a precision socket (which I recommend), you have to cut the pins soldered in the previous step with a side cutter so that the socket sits flush on the PCB.
Soldering is quite fiddly, because you have to solder next to and in between the pin headers. Be careful not to melt the plastic of the pin headers!
The last step is to solder the pin headers for the address lines. When replacing a 2332 ROM, solder the pin headers for address lines A12, A13, A14 and A15. When replacing a 2364 ROM, solder the pin headers only for address lines A13, A14 and A15. Do not solder a pin header for A12!
Make sure to solder the pin headers as straight as possible. In the images below, I use an adhesive like Blu Tack.
Carefully push the adapter into the ROM socket. Mind the orientation - the notch of the ROM socket and the notch of the EPROM socket on the adapter must point to the same direction! Try not to repeatedly insert and remove the adapter - it wears off the ROM socket!
2332/2364 to EPROM Adapter (c) by Patrick Dähne
2332/2364 to EPROM Adapter is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
You should have received a copy of the license along with this work. If not, see https://creativecommons.org/licenses/by-nc-sa/4.0/.