HP2100 memory problems and facit 4070 punch

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