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

  1. #11

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    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:N...ified_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?

  2. #12

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    Quote Originally Posted by ropersonline View Post
    This picture may help with positive connector identification:

    https://en.wikipedia.org/wiki/File:N...ified_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?
    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.

  3. #13

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    Quote Originally Posted by Terry Kennedy View Post
    Congratulations!

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

    Quote Originally Posted by ropersonline View Post
    Will you be retrobrighting the parts of the rack that are now yellow?
    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.


    Quote Originally Posted by ropersonline View Post
    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
    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.

  4. #14

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    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?

  5. #15

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    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

  6. #16

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    Quote Originally Posted by AkBKukU View Post
    I've been getting a very surprising amount of people commenting on that video about the power connectors.
    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.

  7. #17
    Join Date
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    man, that is one CHEAP looking plug
    Screen Shot 2020-01-27 at 10.25.42 AM.png

  8. #18

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    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.

  9. #19
    Join Date
    Oct 2008
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    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.

  10. #20

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    Quote Originally Posted by jafir View Post
    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).
    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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