It boots ADSS again!
We had problems loading diagnostics from paper tape. The paper tape format is 6 bits per stripe that are assembled into an 18-bit word by the paper tape controller and then transferred to core. Most times we would see the low-order 6 bits from one word would be in the high-order 6 bits of the next word. Our guess was that it was missing or getting an extra strobe from the paper tape feed hole. We found that the +10VDC was missing from the little card cage in the paper tape reader. After studying the schematics we found that the +10VDC and -15VDC are supplied through the data cable from the I/O controller chassis. Margin switch #3 and its associated fuses supply the power to many of the I/O cables, and the +10VDC fuse was blown. After replacing the fuse we were able to successfully run the core memory and instruction diagnostics. I imagine that the LINC-8, and maybe the straight-8, have the same paper tape reader and get the power the same way.
We tried booting ADSS from DECtape using the paper tape bootloader. We got lots of parity and other DECtape errors. We tried several different DECtapes, and found one that booted on the first try. So the RICM's PDP-9 is running again after lots of debugging and repairs. I need to reformat the DECtapes on the PDP-9, and then write the DECtape contents using my PDP-8/e so we have more bootable versions of ADSS.
We still need to fix several G850 motor controller FlipChips so we can get the third TU55 DECtape working. If you run ADSS on an 8k PDP-9 you can't have dynamically assigned I/O devices for the compiler so you need 3c DECtapes to compile and run programs. I have spare SCRs and Unijunction transistors for the G850, but so far have been unable to diagnose and repair one.
We also need to rewind a sensor coil for the crankshaft of the paper tape punch, and rebuild the second power supply that feeds +30VDC to the paper tape punch.
I have been collecting the FlipChips for the 34H graphics option so we can play Spacewar! on the PDP-9. I think that I have everything except for the W681 Scope Intensifier FlipChip. If I can't find a W681 I will make one. We also need to add the EAE option to run Spacewar!. We should have all of the necessary Flipchips to do that.
A long range goal is to get UNIX V0 running on this machine. It needs EAE for the filesystem, so we will need that. We could make a disk emulator like the LCM did for their PDP-7, and write a new driver for the emulated disk. I have also been thinking of writing a system driver for the TC02 DECtape controller and using that as the system device. It would not be nearly as fast as an emulated disk, but it would need special I/O hardware either. Comments?