BTW, if there are particular cards you need / are bad, in addition to the actual PDP-12, I have the backplanes and cards for a 2nd one, so if you need something, we could probably work something out.
JRJ On 7/11/2015 8:02 PM, Michael Thompson wrote: > J. Victor Nahigian donated some M221 and M222 boards for the processor and > TC12 LINCtape controller. They are in pretty bad condition, but are > repairable. Warren wrote a test program for the M222 boards, and some of > the just donated boards actually work OK. It will be nice to have some > spares. > > Dan (the donor) brought over the now lubricated top of cabinet fan. He had > to make some special tools to disassembled it but was able to lubricate the > dry bearings. We will reinstall it next week. He also dropped off the > system logbook and more diagnostic manuals. More scanning for Bitsavers! It > is really interesting to see the service history of this system since it > was new. > > The LICM scanned some of the missing MAINDEC documentation so we were able > to run: > MAINDEC-12-D1AC-D Extended Memory Control (EXTMC12) > > MAINDEC-12-D8CC-D_KW12A_Clock_Test Fails test #11 where the AC should be > 0000 and is 7777 on the CLRB instruction. > > MAINDEC-12-D8CA-D-(D) KW12 Real Time Clock Diagnostic (KW12TST) shows the > same failure mode as D8CC. > > MAINDEC-12-D6BA VR12 Display Test Runs, but we have no display connected. > We connected the 'scope to the outputs of the VC12 display controller when > MAINDEC-12-D6BA was running. Without a way to interpret the intensify > signal, and no persistence in the phosphor, the resulting image was not too > good. At least we know that the display controller is responding to > commands and outputs signals that look reasonable. > > We reran MAINDEC-12-D3AD-D-D Tape Control Test Part 1 of 2. > It still fails at 3400 with the error message "LGP GP=GPC PRESET" printed. > > We reran MAINDEC-12-D3GA-D-D Tape Control Test part 2 of 2. > That runs fine. > > I bought the matching terminator for my current probe and was able to give > it a try today. The normal setting for PDP-12, PDP-8/I, and PDP-8/L core is > 320mA. When we debugged the core we set the voltage regulator to the middle > of the high and low voltage settings that caused periodic errors. The low > going part is the read current and the high going is the rewrite current. > The result turned out to be 316mV for the read. Not too bad! >