UPDATE 8/13/2020: The last one has been shipped once again. Since I think we've just about reached market saturation on these, I don't foresee ordering another batch. If you still want one, email/PM me (email is probably the best) steve<at>cton.me and I can send you the drawing files that Protocase used to stamp them. But if demand surges I may order another batch of five to save us all a few $$ (they're not cheap when ordered one at a time, trust me).
Update 12/15/2019: I finally finished putting together my micro-ATX PC a few weeks ago. This weekend I doctored up a web page to show how the whole thing came together. It's not a short read, but there are lots of pretty pictures: https://sacton.neocities.org/altair.html
Old thread with more pictures:
viewtopic.php?f=2&t=213
Installation notes for the Altair Clone:
The backplate is provisioned for three db-25 serial ports. Two come stock with the Altair. The stock wiring for COM1 and COM2 reaches the db-25 cutouts, but it is recommended to extend the wiring to keep it out of the way (DB-25, 5-pin 3.96mm VH connector, ribbon cable). The 3rd DB-25 cutout is for the cassette interface (if installed).
Depending on the motherboard standoffs used, the cassette interface circuit board may need trimmed. Where it needs cut there is no circuitry, and the cassette interface has been tested working after cutting off this piece of its circuit board, like so:
Like COM1 and COM2, the ribbon cable for the cassette interface reaches where it needs to go, but it is recommended to extend it.
There is NO provision for the stock power supply for the clone. Either arrangements have to be made to use it (drill some holes) - or - modify the clone circuitry to run off of 5V instead of 12V (a single wire needs to be soldered on the clone's board) and use the 5V standby voltage from an ATX power supply (see below)
There's enough room beside each 3.5mm audio jack for the "TAPE PLAY IN" and "TAPE RECORD OUT" stickers, and enough room under the PCI cutouts for the Altair Clone's serial number sticker. The serial number sticker is known to lose its text during transfer, so be careful.
Installation notes for the Micro ATX Motherboard:
20mm motherboard standoffs MUST be used. This allows room for cable management and, more importantly, leaves room for the Altair cassette interface. It is recommended to use female-on-both-ends standoffs to gain wiggle room during installation.
The ATX power supply is very close to the plate mounting holes on that side. Standard 1/4" #6-32 case screws will fit without touching a power supply.
There are cutouts for two 92mm cooling fans. It was designed to allow installation of an Asetek 645LT AIO liquid cooler in the cooling fan cutout closest to the ATX power supply. (well, it was designed for the discontinued 545LC, they have the same footprint though). A Hardware Labs Black Ice Nemesis 92mm radiator WILL FIT.... if you leave it and the power supply loose and tighten them both down at the same time. They WILL BE TOUCHING. There's one of them installed in one of the photos of the eBay listing.
The PCI cutouts are designed to use the edge of the motherboard as the bottom PCI anchors. So before tightening the motherboard down, ensure there's enough room for the bottom of PCI cards to slide between the plate and the motherboard.
If using a screwdriver, the PCI mounting screws are hard to get to with the DB-25 serial ports in place.