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Just to be clear, with pre-populated I mean all the off-the-shelf stuff like capacitors and resistors that the PCB manufacturers have in their pick-and-place machines anyway.

IMHO getting a pre-populated board is a good idea, not only to reduce the work but also to cut down on avoidable errors. And unless you get a stencil and a reflow oven it'll probably be neater as well.

View: https://www.youtube.com/watch?v=PcP60-0NIEw

Thanks. At least they provide schematics! The proto area on the prog board didn't seem to have a impact on the cost at JLCPCB, and it gives the option to experiment with extra hardware, like an FPGA for an ASIC implementation, or a USB controller for debugging. IIRC the 4 layers didn't have a...

Do you have a link? (It is perfectly fine for them to do this, BTW.)

There was already a board in use before I released my gerbers. There is no magic in this, the char board is mostly a "dumb" memory board, once you have worked out the pinout by tracing the connections on an original cartridge you can make your own. The prog board needed a bit to reverse engineer...

I think the Lydz board doesn't use it either. I feel like there must be a Chinese "街机项目" forum where people have a bit more information, but the language barrier gets in the way of working together.

Yes, explored in this very thread: https://www.arcade-projects.com/threads/repo-mvs-cart-pcb-discussion.20048/page-2#post-310183 ;) Two problems: Space and money. Adding all the logic chips in DIP packages takes quite a bit of space, moving to SMD increases the difficulty. And all the separate...

Getting this to work with the PLCC84 version would be perfect for those reasons. It is quite possible that I made some mistake when setting up the project. It is a bit of a pity that they are out of production, but there should be still enough NOS for quite some time.

The _dual version has the menu, so you don't need a jumper. Ketsui doesn't have a menu, it just has two versions of the game in different banks.

You were always able to do that, but it costs extra.

Just a quick note for your next order, if you tick "Order Number (Specify Position)" it should put the code they use to identify your PCBs under one of the DIP sockets, so it isn't visible after assembly. They don't seem to do this automatically, even though the placeholder "JLCJLCJLC" should be...

Small update, I was able to erase a atf1502 with disabled jtag using the instructions from https://www.hackup.net/2020/01/erasing-and-programming-the-atf1504-cpld/ This uses a 12V boost converter to create the programming voltage, and I used a 1k resistor I had laying around to limit the...

Ok, to give a bit more detail: The 100 ohm resistor R1 is required for the PGM to recognise the cartridge. All original cartridges that I opened up seem to have it, when I put together the first prog PCB it didn't work until I added the 100 Ohm resistor. R2-R4 can be used as pull-up resistors...

I just spent almost a day programming a 27c400. Not sure if the chips were bad or the algorithm is broken. It failed every few byte, but when restarted it worked fine and failed a few byte later. Since I'm lazy i just installed an auto-clicker to keep pressing the Write button, and now it was...

Use the same schematic but use those tiny push buttons? Maybe with a 3D printed case?

P-ROMs are not the problem, there is enough space for 4x27c322. The problem is C-ROM on the char board, which is limited to 8x27c322, and I think there are games requiring double that. And I don't think I can do some of the fix banking without using an FPGA.

By the way, in case anyone is curious this is the manual for a Pro Logic II encoder: https://professional.dolby.com/siteassets/pdfs/dolby-surround-and-pro-logic-ii-encoder-dp563-manual.pdf Appendix A has some guidelines how to mix audio, though this is for offline production like movies or...

PAL/GAL have a "protection fuse" that is usually written at the end of programming. While it is set all reads return "1", except for a few signature bytes at the end of the fuse map on some devices that can be used to identify the program. If the PAL/GAL is completely combinatorial (i.e. doesn't...

The PGM checks the copyright message in the cartridge header when it gets switched on, if that fails it jumps into the BIOS menu. So check the program board that the EPROM is correctly seated and the GAL correctly configured.