I've done a lot on the build(s) since last post. Just been too busy to update the thread. But here are some of the high points:
I've got a couple of builds going simultaneously. The main reason is just to have spare parts. But it also lets me make two configurations that are slightly different. One has the 18-slot backpanel and the other has the 9-slot board.
I've also experimented a little with the nine-slotter, mostly in respect to the card cage. But I'll post info about that in the "
3D Printing Service" thread, which is predominantly about options for getting card cases made for the 9-slot backplane.
As I said, I've made two builds and powered them both up in a minimal configuration. They each have (1) 8080 CPU board, (1) front-panel interface and (1) FDC+ board configured to expose its 64Kb memory. I can examine and modify memory locations and I have entered and run "Kill the Bit."
- Bare-bones Altair 8800c
I use a pair of four-position barrier strips to distribute power. One is for the AC input side and the other is for the DC outputs from the power supplies. The DC lines are black (gnd), red (+8v), violet (+16v) and blue (-16v). The AC strip has two for line and neutral, straight in from the AC line. The neutral is black and line is white. Black is distributed to the neutral input on all power supplies. White goes out to a panel-mount 3A fuse and comes back to the third AC barrier-strip position. That goes to the power switch connector on the frontpanel, and returns to the fourth AC barrier-strip position. The fourth position is what runs to the line input on all power supplies. I also run the fan off that. Earth ground is green and isn't connected to a barrier strip. It runs to chassis ground and to all the earth-ground connections on each supply.
Now for something that may be seen as pure sacrilege.
I installed blue LEDs on the front-panel for the second system.
- Altair 8800c front-panel with blue LEDs
It definitely doesn't look original that way but I think it looks
awesome. I'm pretty sure if blue LEDs were around when Ed Roberts made the first Altairs, he would have used 'em. I just thought my Altair 8800c - being a "restomod" of sorts - really needed blue front-panel lights.
So the one I'm making with the 18-slot backplane will have a red (original-lookin') front panel and the one with the 9-slot backplane will be sportin' blue.