Updates on repairing Xerox Alto

[Eric Smith]

  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 
anything.

>   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.

Eric