ITXPlus: A ITX Sized Macintosh Plus Logicboard Reproduction

[max1zzz]

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.)

Pins are 12.7mm in length (Which is the lengh of the pin above the plastic part) specifically they are these ones https://uk.rs-online.com/web/p/pcb-headers/2518351

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.

Could have been form my bench too there's far more random SMD components floating around n there than there really should be so it might have got stuck on there when I was desoldering the chips form the donor stick, either way if you can't see anything missing from the board it's not a issue

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.

Personally I used either one of Stirri's water washable flux pastes (I can't remember the exact tone off the top of my head but they are all fairly good) or Chip Quick TF43000

 

[sfiera]

Do you have any brand recommendations? I see DigiKey sells a pine rosin based flux made by MG chemicals, and they presumably don’t stock “questionable” brands.

I’ve been using MG Chemicals’ 8341-10ML from Mouser (probably the same one you’re looking at on DigiKey) and have been happy with it. I think I initially got it on a recommendation from JDW. The big plus, of course, is that I can throw it into a Mouser cart whenever I’m I’m picking up something else.

I wouldn’t go so far as to say everything on Amazon is bad, but it’s a big red flag for me when a brand does not seem to exist outside of Amazon.

 

[Tashtari]

So I've been thinking a little about bringing soft power to the ITXPlus...

I didn't think the keyboard controller firmware could fit anything more in it, but it turns out I was wrong, and I've come up with a mechanism to let the PS/2 keyboard have control of the ITXPlus's power button. Powering the keyboard controller from the +5VSB rail, any key on the PS/2 keyboard can be configured at build time to be the power key and will only press the power button if power on the main +5V rail is not detected. That takes care of soft power on...

Soft power off, however, is a little more complicated. The idea I've implemented in the keyboard controller is an extra undocumented command sent to the Plus keyboard that signals it to turn power off, the idea being that an extension of some kind will send it when the user does Special→Shut Down. The problem is, I don't know how to implement such an extension. It seems like it should be a relatively simple job for someone with a background in classic Mac OS software development, though it is, as always, dangerous to assume that something I don't know how to do is simple...

Anyone out there able to opine on the subject?