Hazeltine 1500 screen garbage; ideas?

[Dennis Boone]

 > Preliminary to setting up all the rest, I thought I'd try getting the
 > Hazeltine working. I plugged it in and powered up, but the screen seems
 > to be displaying random characters constantly while flickering... it's
 > like somebody is sending a binary file over the serial line, except the
 > serial line isn't connected to anything.

Can you tell if the cursor is moving?  If you can and it's not, you
might have some bad video RAM.

De