PDP-12 Restoration at the RICM

W contacted David Tumey about Teletype hammers. He will send us some as a donation. We put some heat-shrink tubing on to stop further damage. Warren repaired and tested the M706 Teletype receiver. We put it back in the PDP-12 and put the borrowed M706 back in the PDP-8/I. The donor brought another M706/M707 pair, so we tested them and then installed them. We have two working serial ports in the PDP-12. Warren is making an Arduino based programmable baud rate generator for this system. We ran more diags. The 8/I Instruction Test #1 & #2, and the random JMP, JMP-JMS, ISZ tests work OK. The LINC Tape-Quickie test and the Memory Address test fail after running OK for a few minutes. We tested all of the G221 Memory Selectors, and they are OK, so the memory address decoding is probably working OK. This may be a case where the processor is sometimes doing the wrong thing when comparing numbers, and the rest of the hardware is actually OK. Debugging this will be the project for next week. The donor dropped off more documentation, spare parts, LINC tapes containing the DIAL operating system, and an RK05 disk pack that likely contains OS/8. We will make image copies of the LINC tapes and the disk pack. -- Michael Thompson