Teeprom
Parts
PCB: OSHPark or PCBWAY
BOM: https://www.digikey.com/short/pbch8c
Carrier: Shapeways or Sculpteo
Programming
To write the eeprom, you need:
- Programmer such as TL866
- SOIC-28 test clip such as Pomona 5437, AP/3M 923660-28, AP/3M 923665-28
- dip-28 socket
- 28 jumper wires with male pins on one end and female Dupont style sockets on the other end.
- rom image files
Put the female ends of the wires onto the test clip.
Put the male ends of the wires into the dip28 socket.
Put the dip28 socket into the programmer.
Remove the Teeprom from the Model 100/102/200
Clip the test clip onto the chip on the Teeprom module.
4ROM
4-bank module that fits in the socket and holds 4 rom images.
https://github.com/bkw777/Teeprom/blob/master/4ROM.md
Sources
The PCB is maintained on github: http://github.com/bkw777/Teeprom
The carrier is maintained on github: http://github.com/bkw777/Molex78802_Module
If you want to get the carrier printed by another service, get the STL file from the github repo and upload it to any other appropriate service such as Weerg, CraftCloud, etc.
It's important to use the appropriate printing technology for this part. Currently the only commonly available / practical printing method that is both accurate enough and produces a functionally strong enough part is SLS. Print with any other method at your own risk. Some notes about the common options:
- FDM / Fused Deposition: Essentially not printable by FDM. I have managed to print this on my own FDM printer (Creality CR-10S). It was just barely accurate enough to fit, but too weak. Broke quickly.
- SLA / Stereo Lithography: Prints extremely accurately and would fit perfect, but is too fragile. Might have luck wth one of the fancy new tough resins, but not with standard resin.
- MJF / Multjet Fusion: Not accurate enough. I tried several times from ShapeWays. Looks almost perfect visually, doesn't fit well enough.
Some print services offer extra high resolution options for their SLS printing. Sculpteo offers a 60um option which is about twice as high resolution as normal. This does come out very nice, but isn't necessary. The Standard SLS raw nylon 100-120um from Sculpteo, or the standard/cheapest option from Shapeways, is already perfect.
Some print services offer dye and other post-processing options. Be careful with those as they can change the final fit. Raw nylon with or without plain dye coloring finish is always fine. Sculpteo also offers some gloss and paint finishes. I have not tried any of those yet. The added layer of paint may possibly cause a problem.
PCB ordering notes
Min Track/Spacing: 6/6mil - On PCBWAY the ordering page may come up with 5/5 or even 4/4 pre-selected, rasing the cost a lot, but this board does not actually have any such narrow traces or gaps. Just manually switch it to 6/6
Solder Mask: Any, but some colors result in either higher cost or longer wait time. The "yellow" color is not really yellow. It's more like a clear coat that looks orange-yellow just from the copper.
Surface Finish: ENIG