HP2100 memory problems and facit 4070 punch

From: Jay West <jlwest_at_tseinc.com>
Date: Mon Jul 26 17:23:29 1999

Thanks to all who responded to the memory parity problems I was having on
the 2100. I have gotten further...I'll share the info in case anyone else
runs across this... basically all memory needs to be cleared. Note - this
applies to the 2100's, not the 21MX's.

Take off the front panel cover by removing the 4 allen head screws. Turn on
the power, and select the M register. Press clear display, then hit memory
display and clear display again (ie. set location 0 to 0) <grin>. On the
lower left of the front panel board is a switch, move it right. Then move
the switch on the upper right of the front panel board right too. Finally
hit the INC M switch. This clears all 17 bits of all memory present in the
system (16 data + 1 parity bit). Move the two switches back left and button
her up. I believe the two switches are instruction lock and step lock IIRC.
Suddenly the memory test is working well now. I'm swapping 8k boards one at
a time to locate any bad ones.

Back on the 4070 punch..... The standard HP punch (I forget the model, 2785
or something comes to mind) used an 8 bit duplex register board. If the guy
I got this facit 4070 from really did use it on the HP at least, I wonder if
it was hooked up to the 8bit duplex board like the normal HP 2748B paper
tape reader was. Just a thought....

Thanks for all the help folks!

Jay West
Received on Mon Jul 26 1999 - 17:23:29 BST