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New to Minicomputers with Data General Nova 4/X and microNova 8561

AkBKukU

AkBKukU

Member
Joined
Jan 29, 2017
Messages
48
Location
Chandler, AZ
I recently had the incredible opportunity to be able to pick up a very complete Data General Nova system set. I went into this knowing essentially nothing and did as much research has I could before buying it and picking it up. What I ended up with are a 16 slot Nova 4/X and a 9 slot microNova 8561.



The person I bought the systems from was the original owner and it was a surprisingly nice experience because they fully understood that this was a significant system and they wanted to see it go to a good home. They allowed me all the time I needed on premises to disassemble it for transport which was good since I spent 3hrs on that alone. Thankfully I also had help because some of the hard drives are insanely heavy and moving them alone just isn’t an option.

Yesterday I finally finished setting it all back up as it was and am now ready to begin the process of restoring them. I was able to ask about the last time they were used and was told “35yrs ago”. But I suspect it was just a little more recent than that because I got DG service logs for these and they run into 1989 at least. But it’s not like 5yrs makes that much of a difference. That’s to say I’m definitely not going to just plug them in and try to fire them up. I’m going to go through everything and attempt to recover each part. I’m going to be reforming a lot of giant capacitors.

Ok, so here is how each machine is configured.

The large cabinet, pictures: https://imgur.com/a/4gdhHxS

  • 6103 25MB Fixed Disk
  • 16 slot Nova 4/X
  • 6045(6050?) 5MB Removable + 5MB Fixed Disk
For the 6103 I tried my best to research transporting the HDDs before doing it and learned that the locking controls are under a plate on the bottom. While there I was able to lock the spindle but had difficulty locking the heads. Yesterday while setting the drive back up I removed the top cover and discovered that I couldn’t lock the heads because they were not parked. It would have been possible to manually move the stepper and re-position the heads and then lock them. But I didn’t know this at the time and didn’t want to dissemble the parts more than needed for transport. So ultimately this spent a 2hr drive with the heads over the disks. The platters were locked so it would have only touched one spot. I couldn’t see any marks on the visible side of the one platter so perhaps it will have survived. I have no idea what condition the heads may be in though. Everything was stored on about 2in of padding so I may have prevented the vibrations from destroying it.

The back of the cartridge drive is labeled both 6045 and 6050 but it seems like it’s most likely a 6045 from what I’ve seen online. The cartridge bay has… mouse droppings in it and there are mouse footprints in the dust in the bottom of the case. So I’m hoping the wiring hasn’t been chewed up inside. I haven’t opened it yet because these are the stupidly heavy drives.


The Nova 4/X has the following cards, pictures: https://imgur.com/a/v3BY5UB

  • CPU Board
  • PSU Board
  • Memory
  • “DISC LOGIC NOVA” / 6103 Fixed Disk Controller
  • “DISC CARTRIDGE CONTROL” / 6045 Removable+Fixed Disk Controller
  • Sync-Async Controller:
I’m a little disappointed that they didn’t get the computer with the Mul/Div board. So now I’ll be hunting for that to try and upgrade it. But that’s a long ways out right now.


The shorter cabinet, pictures: https://imgur.com/a/rgFruez

  • microNova 8561
  • 6095-N “10MB SUBSYS”
  • 6039 Floppy Disk Drives
I’m not really sure exactly what the 6095 drive is. I can’t find any significant information for a “6095” drive like I can for a 6045. It seems very similar and had a CDC 848-12 disk cartridge in it when I picked it up. I’m inclined to think it is another 5MB + 5MB drive like the 6045. I would like to find more information on it though.


Now for the microNova I’m also not sure what it is exactly. Online I’m seeing model numbers like “MP/100” but this one only seems to be marked as an “8561” and I don’t see anything else on the CPU board. But here is how it is configured(spoiler, RAM!)

Pictures: https://imgur.com/a/4ZZSsiB
  • CPU Board
  • 4k/8k Memory
  • 4k/8k Memory
  • 4k/8k Memory
  • 4k/8k Memory
  • Full Async
  • Partial Async

And the last big component I think is in the running for the most beautiful computer peripheral ever created. A 6053 Dasher D2 Terminal:
zG8CVnZ.jpg
fTwed9S.jpg
8z7BVgb.jpg



Some additional things that were included were a CDC 100 Disk 8” floppy box: https://imgur.com/a/DDjMJFd

And the service logs from their service contract with Data General for both machines. I’ll put up all the pages (censored for personal info) in separate albums to go through.

Nova 4/X: https://imgur.com/a/cpmjoou , microNova: https://imgur.com/a/FzTVzbr


Okay, that’s it for what I’ve got. This is an overwhelming system when you look at it as a whole. So I’m going to be looking a working on this in stages. I think the first thing I’m going to start on is the Dasher D2. It would be nice to have that up and running to use with the systems when I make more progress on them. I can of course use a USB-RS232 adapter and a terminal emulator on PC or just connect the TRS-80 DT-1 terminal I have to it. But the Dasher is a low bar to get something working more quickly from this.

That’s the easy part though, bringing the computers online is a daunting task. I’d welcome any input on how to start with that. I am already planning on removing the PSUs and getting those working independently first. I haven’t opened them up yet to get a look at what I’m up against, but I can see some absolutely massive capacitors that I’m going to likely need to reform. I’d welcome advice on how to proceed with that because I haven’t done that before.

I’m still gathering information resources on these systems and haven’t really reached much out to anyone before or after getting these for information and advice. So I’d welcome any input really on this. I’m hoping the HDDs will function and contain RDOS on them. If not, is there a way to make disks? As I get closer to getting the microNova going I’m going to start looking into getting an 8” drive to connect to a PC , kyroflux, or whatever I need to make disks if possible. It is my intention to get this all restored and working as much as possible and to make it usable again.


Albums:
Nova 4/X Cabinet: https://imgur.com/a/4gdhHxS
Nova 4/X Cards: https://imgur.com/a/v3BY5UB
microNova Cabinet: https://imgur.com/a/rgFruez
microNova Cards: https://imgur.com/a/4ZZSsiB
Dasher D2: https://imgur.com/a/ZPNGLKs
8 inch Floppy Disks: https://imgur.com/a/DDjMJFd
Nova 4/X Service Logs: https://imgur.com/a/cpmjoou
microNova Service Logs: https://imgur.com/a/FzTVzbr
 
Chuck(G) said:
I'm sure that the DG source of all knowledge, Bruce Ray would love to hear about your system and fill in any gaps in knowledge that you might have.

You can write him in care of his firm "Wild Hare Computer Systems"
Click to expand...

I'll be sure to get in touch, thanks!

commodorejohn said:
Oh, drool. Looking forward to hearing about this :D
Click to expand...

Well, I'm really trying to hold my self back so I don't rush and damage anything. I've only got one shot to get these working so I need to make sure I don't make any mistakes. So I'm going to be going slow on this. I'm in no real rush on these. Outside of getting them going, I'm happy to answer questions about them! I've had a really hard time finding info about these and I'd be happy to document anything here for someone if it can help. Or just answer questions for the curious as well.
 
Nice buy! ... saw this on eBay when they first put it up for $499 Buy it Now, and thought about picking it up for the racks, drives, and the D2 for my S-130, but the shipping killed that idea, then they took it down and price was doubled when it was re-listed. Lot of good stuff there!
 
firedome said:
Nice buy! ... saw this on eBay when they first put it up for $499 Buy it Now, and thought about picking it up for the racks, drives, and the D2 for my S-130, but the shipping killed that idea, then they took it down and price was doubled when it was re-listed. Lot of good stuff there!
Click to expand...

It is indeed that listing. I didn't see the $500 BIN option before... I got in touch with them over facebook marketplace where there wasn't an option like that. I have no idea what this is worth really, but I'm happy with the purchase and that's all that really matters to me. I agree it's a good set for sure! I'm really excited to bring it back to life!
 
AkBKukU said:
I recently had the incredible opportunity to be able to pick up a very complete Data General Nova system set. I went into this knowing essentially nothing and did as much research has I could before buying it and picking it up. What I ended up with are a 16 slot Nova 4/X and a 9 slot microNova 8561.
Click to expand...
Congratulations!

The 6045 is the DG in-house version of the 4234 (Diablo 44) 5-over-5 drive. Media should be compatible. The MicroNova is (as you might imagine) a microprocessor-based implementation of the Nova instruction set. It isn't as slow as you might imagine if you compare it with the '181-based hardware (Eclipse S/200 and probably Nova 3). I believe the Nova 4 is 2901 or 2910-based, and is pretty much a Nova-ized Eclipse S/140. I'm amazed at how few boards there are in there that are needed to make it work. The S/200 I managed at SPC had a pretty-much stuffed 16-slot backplane, plus a comm chassis full of ALM serial cards. But I had evolved it from a 32K core-based S/200 with 4234 to a MOS-based S/230-equivalent system with a 6061 for user files and an AOS paging disk drive as the system boot device. DG pretty much gave up and decided "sell him anything he wants and let him figure it out". At one time I had a 64-terminal XBASIC system (yes, I'm THAT GUY who wrote the infamous "XBASIC can use any 32 terminals, as long as they're the first 32" STR).
 
ropersonline said:
Looks like the customer and serviceperson had a big fight over whether cooling-wise it was better to run the machine with covers off or on. :)
Click to expand...
Same thing with my S/200. I ran it with the back doors off and DG Field Circus* wanted them on. Now, this was with an S/200 which had left-to-right boards, not front-to-back like later systems, so things were a bit different.

* A couple of fun stories -

When out system was off maintenance contract, either in a misguided attempt to save money or because DG couldn't figure out how to write a contract for what was essentially a homebrew S/230, the repair people would show up in the AM, unpack their tools and putter for a little bit, then go out for "lunch" (still 'on the clock') to a local pub, come back quite lubricated**, drunkenly pack up their tools and leave. Lather, rinse, repeat for a few days. Now, this was back in the late 70's / early 80's when they still did chip-level diagnosis and repair, so there weren't spare boards to use to try swapping while they were out. I did manage to snag an extender card (I don't have any of this except memories any more), though.

** Field Circus (at least in the NYC area) at one time had these forms to help automate analysis of service call / repair reasons. They were (IIRC) 3 parts where there were numeric codes for each section, which were verb / noun / something. So it might be 00 = no problem found, 01 = adjusted, 02 = aligned, 03 = replaced, etc. for the first part and 01 = component, 02 = board, 03 = disk drive head, etc. for the second. You get the idea. When they started analyzing the stats, they found that "lubricated customer" was the most commonly reported thing. The techs couldn't be bothered to look up codes in the little pocket reference guide and write them down on the NCR-paper trouble / repair ticket, so they just used something they'd written down on the cover. It started as a single-tech joke and grew into at least this region.

On the S/200, the backplane has a load of AGA (stubby 3AG) fuses***. One newbie tech went to pull one of those from a powered-on (but non-working) system and I said "you want to measure the voltage drop across it while running instead". He said that he wanted to measure the out-of-circuit resistance instead. I told him that that would show a good fuse no matter if it was good or bad. He went to pull the fuse and I said "you REALLY don't want to do that". He grabs the fuse between his thumb and forefinger to pull it and goes "YAHHHHHHH!" because it was burning hot due to heat being dissipated from what had essentially turned into a 50W power resistor. He had an impression of the fuse burned into his fingers. A few years later, when the Indiana Jones movie came out and the bad guy gets an image of the medallion burned into his palm, I thought of the tech with the fused fingers.

*** Which are VASTLY better than the "pico fuses" that littered all of the boards**** and the backplane.

**** Jumpers on this era of board were gold-coated wires that were bent into a wide "U" shape and stuffed into 2 pins of sockets with several rows on the PCB. After a few in-out-in cycles they got bent and fell apart. We discovered that "mini" staples had the same pin spacing (narrower than regular staples) and I started using those. They worked remarkably well, since they were hard metal and square, so they worked almost like reverse wire-wrap sockets, making an air-tight seal between the pin and the socket.
 
I've just had a look at your YouTube video. The connectors look like they could be NEMA 10-30 or NEMA 10-50 (or maybe L5-30 or L6-30) and NEMA L14-30, which if true could have grounding implications according to Wikipedia; see:

https://en.wikipedia.org/wiki/NEMA_connector#NEMA_10

This picture may help with positive connector identification:

https://en.wikipedia.org/wiki/File:NEMA_simplified_pins.svg

In case the minicomputers really do expect 240V, would 120V-to-240V step-up transformers be usable to give you what you need?
 
ropersonline said:
This picture may help with positive connector identification:

https://en.wikipedia.org/wiki/File:NEMA_simplified_pins.svg

In case the minicomputers really do expect 240V, would 120V-to-240V step-up transformers be usable to give you what you need?
Click to expand...
On the S/200 that I had, the power was a 4-pin straight prong plug (hot / hot / neutral / ground) and the outlets in the cabinet were on one leg or the other - no 230V. That connector was obsolete before the S/200 was installed - in fact, when we moved the computer room to a new building it was easier to take the outlet with us than to find another one. Speaking of obsolete, the circuit breaker in the bottom of the cabinet was a 2-pole Pushmatic.
 
Terry Kennedy said:
Congratulations!

The 6045 is the DG in-house version of the 4234 (Diablo 44) 5-over-5 drive. Media should be compatible.
Click to expand...

Thanks!

That's really good to know that they should be compatible. I don't know if I'll have any other way of transferring data between systems. So that will be very helpful.

ropersonline said:
Will you be retrobrighting the parts of the rack that are now yellow?
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I definitely will not be. If there is any chance at all that retrobrighting damages plastic it's not worth the risk on something this rare.


ropersonline said:
The connectors look like they could be NEMA 10-30 or NEMA 10-50 (or maybe L5-30 or L6-30) and NEMA L14-30
Click to expand...

They are L6-20 and L14-30 (and I do have the cables that connect to them) but I'm really not that worried about the cabinets power connectors. All of the devices internally have standard US outlet connectors. The cabinet power connections are just for the internal power distribution and can be easily bypassed.
Screenshot_20200120_075957.jpg

I've been getting a very surprising amount of people commenting on that video about the power connectors. They are so incredibly low on my list of priorities compared to the other things I may have to solve like replacing the drive heads. If I'm ever in a position where I can get high current/voltage circuits installed for these systems I'd likely hire an electrician and have them take care of it. That's not in the cards for a long time though.
 
Those floppy disks that were bundled with the microcomputers look very interesting yet mostly have very vague labeling. Do you have any plans about sending them to someone to get their contents imaged or doing that yourself?
 
Very nice and quite rare (the MP that is), welcome to the world of Data General!

There is little on the web re Data General and as others have suggested, Bruce @ WildHare is the font of all knowledge on DG.

Regards

Sean
www.datageneral.uk
 
AkBKukU said:
I've been getting a very surprising amount of people commenting on that video about the power connectors.
Click to expand...

I think that's just because you gave the impression that they were unusual. I don't think people are trying to be rude or anything, I know I wasn't when I commented, it's just that most of us that are working on enterprise equipment see those connectors every day, so we just wanted to make sure you know they aren't rare or special. I'm just glad they aren't 3 phase. I don't know about DG stuff, but I know a lot of old enterprise stuff, and even the stuff I install today can be ordered with 3 phase.

For the 120 volt stuff, if you aren't using close to half the amps, there are cheap adapters that you can use. (I know a lot of people will go crazy at the thought, but I've got a UPS with an L5-30 plug, and it's built in monitoring says it never uses even half that many amps they way I have it loaded, so I'm not worried about it).

This one is $13 right now. https://www.amazon.com/gp/product/B01CKRKWH6 This is actually safer than trying to go from L5-30 to a lower amp plug, because if you use more than 15 amps, the breaker will trip so nothing should melt, where if you plug a 15 amp device into a 30 amp outlet, and something bad happens, the breaker won't trip until 30 amps of smoke and fire :) Though there are adapters that have fuses in them to make them safer.
 
Yeah, a better idea might be to build your own adapter with name brand plugs and receptacles from the hardware store, at least that way you know if you got good components or not. I've not had any issues with the one shown, but I only power up my little half rack a couple of times per year to test something. At some point I plan on getting a dedicated 30amp circuit, but I always end up putting it off because if I do that, I should probably do 240v instead of 120v.... I'm so indecisive sometimes.
 
I've had pretty good luck with plugs and outlets made by Cooper when similar products were not available or more expensive from Leviton or Hubbell.
When I built my racks I found their twist-locks were $10-$20 cheaper per plug.
 
jafir said:
For the 120 volt stuff, if you aren't using close to half the amps, there are cheap adapters that you can use. (I know a lot of people will go crazy at the thought, but I've got a UPS with an L5-30 plug, and it's built in monitoring says it never uses even half that many amps they way I have it loaded, so I'm not worried about it).
Click to expand...
If I may digress...

Back in the 80's I made the ultimate stupid adapter - L21-30P (30A 3-phase) and the stupidly expensive (several hundred 1980's dollars) 60A Russel-Stoll receptacle that a VAX 8650 was expecting to plug into. This was so I could roll out a VAX 785 and roll in an 8650. i think DEC just used that obscene plug on the 8650 because they wanted to convince people it was a mainframe (and could be rolled in to replace various IBM 370 CPUs that used that same connector). The 8650 ran for many years until it was decommissioned, using that 60A to 30A adapter. The panel circuit breaker for that outlet never tripped, so the 8650 never used more than 30A.
 
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