• Please review our updated Terms and Rules here

Data General Nova 1200

Mysterious additional pages, never made any sense to me.
 

Attachments

  • 093-000038-00_Debug_I_0014.jpg
    093-000038-00_Debug_I_0014.jpg
    91.2 KB · Views: 7
  • 093-000038-00_Debug_I_0015.jpg
    093-000038-00_Debug_I_0015.jpg
    200.9 KB · Views: 7
  • 093-000038-00_Debug_I_0016.jpg
    093-000038-00_Debug_I_0016.jpg
    135.2 KB · Views: 6
  • 093-000038-00_Debug_I_0018.jpg
    093-000038-00_Debug_I_0018.jpg
    160.6 KB · Views: 5
  • 093-000038-00_Debug_I_0019.jpg
    093-000038-00_Debug_I_0019.jpg
    76.5 KB · Views: 8
Wow, that's way better then my copy! Now if i can only find a copy of Basic for the system. Do not care if its a print of the code being if it were five hundred lines I would still toggle it in. do have a paper tape punch and have to look into finding a way of pushing a batch file thru the com port to have the printer print a tape, know how to read tapes all day long or how to copy tapes but having the ability to compile code into a batch file and push it to the punch is still eluding me.
Remember, I do power systems, drives and racks, not software.
 
Last edited:
Thank you for providing those scans, Qbus.

Excellent. I've been compiling a list of programs, resources, and various links to the Nova community at large here: https://www.commodorez.com/novarsc.html


1664942120941.png

The latest development in my 1200 debug progress has been the fixing of the fault on the front panel. We don't seem to have schematics of a Nova 1200 front panel, the best we've got is a Nixdorf DSS 620, a clone that's close enough to reference when debugging. Initially, unresponsive AC3 Examine, Deposit, and Examine pointed towards U1 and U2 having been damaged by the power fault I had previously uh... encountered. After replacing them, with no operational change noted, this pointed towards the Console Request (/CON RQ) signal itself, which tells the CPU that the front panel has a message for it. The large signal line running across the top gets pulled about a volt lower whenever a momentary switch is pressed, which is then converted into a proper logic level low by the transistor and inverters. However, watching the voltage when AC3 EX, DEP, or EX were pressed, the voltage didn't go low enough to trigger the rest of the logic.

I measured the 5V source at the front panel, and found that it had drooped down to 4.84V or thereabouts. I tweaked the output at the supply to compensate for the droop, and suddenly CON RQ began to respond every time it should. Some of the resistors in that section of the front panel have drifted just enough to be a concern, replacements are on order right now. Either way, the switches that had been acting flaky are now consistently operating, and the power supply voltage isn't too crazy. Remember, the nominal suggested voltages from the factory is closer to 5.25V, and I'm not thrilled about boosting the power supply that high.

Anyway, since then I've been testing out various diagnostic programs. Checkerboard III and IV in particular are of interest, but I'm finding the instruction manuals to be rather vague about what to expect from a working vs. malfunctioning system. I've also yet to get the Nova 1200 Logic Test diagnostic to run in such a way to indicate that it's even trying to run.

At one point, I tried loading the Binary Loader routine over serial, as I had done so many times, and it was encountering errors that prevented the program from successfully loading. Erratic terminal response, failure to halt the Bootstrap Loader routine, that sort of thing. On a whim, I pulled out one of my two core memory boards, and tried again, and magically it worked that time. It's been an essential way of loading up these diagnostic routines, so when that starts failing unexpectedly, it's quite discouraging.

I've also tried loading up BASIC, and it never makes it past the first user response to the initial configuration prompt. Halts the CPU solid.

So, here's what I'm looking for right now:
Nova 1200 Logic Test diagnostic manual
Nova 1200 Technical Manual which will include the first-time startup procedures in order. Thus far, I've been working off of a mix of the 1220 and 800 tech manuals, but they're not precisely tuned for a straight 1200.

I'm also curious what nominal, expected operation of Checkerboard III, IV, and Logic Tests is supposed to look like from someone who has had experience running these pieces of software.
 

Attachments

  • Nixdorf_DSS_620_Schematic_Book_-_DG_Nova_Front_Panel_Only.pdf
    2.1 MB · Views: 4
Thank you Qbus. Original document including instructions and source:
Thank you Qbus for discovering and publicizing this debugger in the first place.

Thank you Paul for pointing us to the nice and readable manual with program listing. It may even be convertible to text via OCR.

I am not a fan of toggling in more than say twenty 16 bit values because I am guaranteed to make mistakes.
I have upgraded my Nova 2 with the "Program Load" feature, so I prefer to type in the source code from a listing once and then assemble once and load with the Binary Loader forever, rather than toggle in 16 bit octal values over and over. But maybe that is just me being weird. :giggle: 😜

Tom
 
While we are finding interesting things for the Nova, has anybody come across a working chess program for the Nova 2 or Nova 1200?

Even the "lowly" PDP-8 has Checkmo II which is surprising good. The more capable Nova is bound to have a decent chess program.

Tom
 
So by the time I found out about this, a lot of the stuff had been parted out and some of it scrapped. Apparently the original owners had been trying to work with several hobbyists and amateur radio operators for like, two years or something, and had gotten a lot of "definitely interested, will be by to pay and pick up" type of replies that resulted in no action, and had gotten tired of it.

Most of the DG and Computer Automation stuff was connected to typesetting machines, there were two Kurzweil OCR systems but they were the later integrated packages, not the big early boxes with a full-fledged Nova attached. The Kurzweil stuff may have an OEMed Nova or Nova-compatible board in it, too. I believe they'd told me the Fairchild 2300 (TRW 130, AN/UYK-1...originally a 1950s nuclear sub satellite nav computer) was also hooked up to a typesetter.

We ended up making a second trip up to pick up some other large things that weren't really shippable -- the remains of at least a dozen Kaypros, the guts out of two Linotron 202s that had gotten scrapped, misc. cables and other bits that had been found since the original pick-up, and a box of board scrap that had come from some of the equipment.

I suspect CommodoreZ's Nova 1200 was indeed connected to that Teletype at one point, though the Teletype may have shared service between several computers, such as the Fairchild 2300, which also has current loop output. Don't know what the Nova 1200 in particular was doing, though.

Here's some pictures of the stuff, unloaded in the new building (not everything is from the same lot, in the second picture):





It pretty well filled the back of the 24-foot Mack box truck:



There was a bunch of Sun stuff too, which was one of the big reasons I was interested in the stuff (still support it for my day-job). TangentDelta has been working on a lot of the Computer Automation Naked Mini stuff.
Nice collection!
 
Maybe it’s a form of brain damage or something else, don’t know but I am drawn to that AN/UYK-1 system. I collect old military radios, teletype and computers and that has to be the oldest system I have seen outside of a museum and would be a great project to get up and running. Am assuming that the TRW had a lot of architecture in common with the Nova being 16 bit and four accumulators but that’s just a guess.

In the last couple years have been running teletype using vintage military equipment on forty meters, 7.087 MHz, 850 Hz shift 45.5 baud at 9:00 AM EST on Saturdays, there is a small group of us all running hardware that’s all over forty or fifty years old , lot of model 28 machines and the like. Been thinking of building up a message buffer for transmitting stored messages using the Rolm 1602 military Nova but that AN/UYK would be way more of a challenge!
 
Back
Top