Updates on repairing Xerox Alto
eric at brouhaha.com
Tue Oct 19 23:53:07 CDT 2010
Nick Allen wrote:
> I noticed the cursor is a hardware cursor, does this mean if I get the
> display board working (and if only the display card is working) will
> it output the cursor to the CRT?
No. The microcode has to be running to get the display board to do
> If so, this is great news as I can focus on repairing a single
> board. If not, do you know which boards I need to get working at a
> MINIMUM to get ANY display on the CRT (either the hardware cursor, or
> some sort of diagnostic boot code to output to the CRT)?
Nearly all of them, unfortunately. You could get by with only partial
memory. It's been a while since I looked at the microcode listing, but
I don't think you'll get anything but a blank raster until you get some
code booted and running. You need either the Ethernet or the disk
controller to do that. Since you probably don't have any other 3 Mbps
Ethernet hosts that can serve the boot protocol, you'll need the disk
controller, drive, and a bootable pack.
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