PDP-12 Restoration at the RICM

Michael Thompson michael.99.thompson at gmail.com
Tue Dec 22 19:31:46 CST 2015

Lots more work on the PDP-12 at the RICM. We got an RS-232 console board
and baud rate generator from Vincent and now have both serial ports
working. Warren modified Kyle's SerialDisk and we booted OS/8 from an
emulated RK05 on the second serial port. We fixed one of the bus interface
boards in the DW8E Omnibus expansion chassis, and connected the RX8E/RX02.
We were able to boot OS/8 from an RX01 diskette. We replaced an M160
flip-chip and now the EAE instructions work. We replaced an M103 flip-chip
and the KW12 clock works. This system is new enough that ECO EM12-0055 for
the KW12 was installed when it was built. This means that the KW12 Maindecs
earlier than D8CD will not work. We cleaned up the PC04 paper tape
reader/punch and connected it to the PC8E. The punch works OK, but the
reader does not always step correctly and does not read the tape correctly.
Fixing this will be the next project.

Once we get the PC04 working the next project will be the RK8E/RK05.

Out of frustration we set aside fixing the TC12 LINCtape controller. We see
spikes on data track #3 that corrupt the data. We swapped the TU56 for a
known good TU55, swapped the data/control cable, and swapped every
flip-chip that is related to data track #3. Nothing has eliminated the
spikes. The only part that we have not swapped is the backplane wiring
between the data cable and the G882 flip-chips. Warren has a plan to
temporarily replace that.

We found that the maintenance prints that came with the system do not
include ECO EM12-0055.
Does anyone have a set of KW12 prints that include ECO EM12-0055?

Michael Thompson

More information about the cctech mailing list