ITXPlus: A ITX Sized Macintosh Plus Logicboard Reproduction
- Thread starter max1zzz
- Start date
Those are 16MBit chips (hence, I guess AS4C1M16E5-60JC), meaning 1MB x 16-bit. They're 2MB each. So, 2x DIY SIMMs with 2 chips each would provide another 8MB of DRAM, taking my LC II to 10MB (assuming fixing it is as easy as a recap?).
This is great stuff, Max.
Shut up and take my money! Lol!! Amazing work! Congrats on doing something truly spectacular!!! Count me in for whenever there is something available!!I will indeed have a few for sale soon
Things have been moving a little slowly lately but I'm finally getting things sorted out
For those that wish to purchase boards: https://68kmla.org/bb/index.php?threads/fs-itxplus-pcbs-kits-and-assembled-boards.50166/
And for those that wish to build their own from scratch: https://github.com/max234252/ITXPlus
For those that wish to purchase boards: https://68kmla.org/bb/index.php?threads/fs-itxplus-pcbs-kits-and-assembled-boards.50166/
And for those that wish to build their own from scratch: https://github.com/max234252/ITXPlus
For anyone interested, I've made a daughterboard for the ITXPlus that allows the addition of an IWM or SWIM chip in DIP-28 form. It mates with the 2x12 header on the ITXPlus and provides a pair of floppy headers, ready for your Floppy Emu, TashTwenty, or even actual floppy drive! Also made an adapter board (pictured below) in case you have a SWIM in PLCC-44 form that you want to adapt to DIP-28.
The .brd files and gerbers (see releases) are available on Github:
github.com
The .brd files and gerbers (see releases) are available on Github:
GitHub - lampmerchant/misc-mac-pcbs: Miscellaneous PCBs for Macintosh retrocomputing.
Miscellaneous PCBs for Macintosh retrocomputing. Contribute to lampmerchant/misc-mac-pcbs development by creating an account on GitHub.
github.com
Just got my ITXPlus board in today (really excited, but probably won't have time to fire it up for a few weeks as I'm moving)... regarding the SWIM adapter.. any thoughts to making it in a formfactor such that it can just plug over top of the motherboard header and then exposes the floppy plug upwards or forwards?For anyone interested, I've made a daughterboard for the ITXPlus that allows the addition of an IWM or SWIM chip in DIP-28 form. It mates with the 2x12 header on the ITXPlus and provides a pair of floppy headers, ready for your Floppy Emu, TashTwenty, or even actual floppy drive! Also made an adapter board (pictured below) in case you have a SWIM in PLCC-44 form that you want to adapt to DIP-28.
View attachment 93276
The .brd files and gerbers (see releases) are available on Github:
GitHub - lampmerchant/misc-mac-pcbs: Miscellaneous PCBs for Macintosh retrocomputing.
Miscellaneous PCBs for Macintosh retrocomputing. Contribute to lampmerchant/misc-mac-pcbs development by creating an account on GitHub.
I think that's what this board does, unless by "the floppy plug", you mean a 19-pin D-sub. That's what I would have reached for at first, but as far as I know they're unobtanium...
Hi. I received the kit I ordered and am almost ready to test it, but I had a couple questions I hope someone can answer:
1) Are the "long pin" pin headers on the port board 19mm or 17mm? (I lost one. My ruler says they're 18mm on the nose, so it's off, but I don't know which way.)
2a) Any recommendations for a different brand of flux? Mine ate through the solder mask in spots and other spots are still "sticky" after several rounds with rubbing alcohol and a soft toothbrush.
2b) Regarding the flux/residue, it's acidic, right? Would a baking soda and distilled water scrub maybe be more productive than just more rubbing alcohol? Or is there something better?
3) @max1zzz specifically - When I was removing a RAM chip I soldered on backwards, I found a loose capacitor (one of the tiny SMD ones), for some reason stuck to the underside of the RAM chip. It may have been loose on my workbench from another project, but I have no idea.
I've checked the board over and while I can't find a missing cap, I also can't find account for all the caps visually (missing numbers in the sequence). Would it be possible to get a PDF of the bottom of the board, with all the birdseed searchable (and hilightable) so my terrible eyes can have a cheat sheet?
----
Otherwise, the build process was smooth. I "cheated" for most of the PLCC chips by tinning the pads and blasting them with a hot air solder station until they stopped moving. Which isn't the gentlest way to do it, but here's hoping I didn't break anything.
I still need to go over and check all the chip/pin continuity before I try powering it up. Maybe tomorrow.
1) Are the "long pin" pin headers on the port board 19mm or 17mm? (I lost one. My ruler says they're 18mm on the nose, so it's off, but I don't know which way.)
2a) Any recommendations for a different brand of flux? Mine ate through the solder mask in spots and other spots are still "sticky" after several rounds with rubbing alcohol and a soft toothbrush.
2b) Regarding the flux/residue, it's acidic, right? Would a baking soda and distilled water scrub maybe be more productive than just more rubbing alcohol? Or is there something better?
3) @max1zzz specifically - When I was removing a RAM chip I soldered on backwards, I found a loose capacitor (one of the tiny SMD ones), for some reason stuck to the underside of the RAM chip. It may have been loose on my workbench from another project, but I have no idea.
I've checked the board over and while I can't find a missing cap, I also can't find account for all the caps visually (missing numbers in the sequence). Would it be possible to get a PDF of the bottom of the board, with all the birdseed searchable (and hilightable) so my terrible eyes can have a cheat sheet?
----
Otherwise, the build process was smooth. I "cheated" for most of the PLCC chips by tinning the pads and blasting them with a hot air solder station until they stopped moving. Which isn't the gentlest way to do it, but here's hoping I didn't break anything.
I still need to go over and check all the chip/pin continuity before I try powering it up. Maybe tomorrow.
that sounds like you're using a massively too-aggressive flux - you're not accidentally using like plumbing flux or something are you? (if so, you wouldn't be the first...). I just use ordinary pine rosin based flux, personally, and it works well enough for me (although I don't do a huge amount of SMD soldering)
