DCC-116 E / DATA GENERAL NOVA 2/10 / Nixdorf 620 - Restoring and restarting
AJ Palmgren
microtechdart at gmail.com
Wed May 17 23:05:33 CDT 2017
My search for this was prompted by my seeing one on eBay:
http://www.ebay.com/itm/282462822861
Did anyone here purchase it, or know who did? Just curious, since these
seem so rare and interesting.
Best,
-AJ
On Wed, May 17, 2017 at 8:29 PM, AJ Palmgren <microtechdart at gmail.com>
wrote:
> Dominique,
>
> I'm quite interested in seeing your Entrex/Nixdorf system restored.
> Please keep us updated here. Nice work saving these rare items!
>
> I've done some of my own work restoring a DG Nova-type system. (
> http://Point4iris.com ). I'd love to see if there's any way I could help.
>
> I'll read Christian Kennedy's response here, as he seems FAR more familiar
> and knowledgeable than I am here, but if I can add value in any way, I
> would love to.
>
> Best,
> -AJ
>
> On Sat, Apr 1, 2017 at 12:33 PM, Dominique Carlier via cctalk <
> cctalk at classiccmp.org> wrote:
>
>> Hi guys !
>>
>> My name is Dominique, 43 , from Belgium (I apologize in advance for my
>> approximate English). I join this forum under the recommendations of
>> Curious Marc. It seems there are people here who can help me to get back to
>> life the venerable machine that I have just recovered.
>>
>> Some pictures of the beast :
>>
>> http://www.actingmachines.com/classiccmp_forum/overview01.jpg <
>> http://www.zeltrax.com/classiccmp_forum/overview01.jpg>
>>
>> http://www.actingmachines.com/classiccmp_forum/terminal.jpg <
>> http://www.zeltrax.com/classiccmp_forum/terminal.jpg>
>>
>> http://www.actingmachines.com/classiccmp_forum/comrack_closeup.jpg <
>> http://www.zeltrax.com/classiccmp_forum/comrack_closeup.jpg>
>>
>> It is a "Nixdor 600 series" (Apparently a Nixdorf 620/35), upgraded
>> several times until 1980, the CPU board is dated from this year. So I do
>> not know exactly what machine it is today the equivalent.
>>
>> Anyway, the Nixdorf 620 is actually built by "Digital Computer Controls"
>> and after some researches it seems that it is a "DCC-116 E", the 17 slot
>> version of the "DCC-116" which Is a clone of the "Data General Nova 2/10".
>>
>> http://www.actingmachines.com/classiccmp_forum/DCC.jpg <
>> http://www.zeltrax.com/classiccmp_forum/DCC.jpg>
>>
>> The machine has five Key-stations (ENTREX DATA/SCOPE), a Mag-tape Pertec
>> 8840A - A Disk Cartridge Diablo Model 40 and a big line drum printer (Data
>> Products model 2230), strange machine, there is a tape reader inside the
>> printer.
>>
>> Here is the list of the boards I have with the references written on them
>> and their position in the machine:
>>
>> *17 HEX 0 – 15 ENTREX INC 62 00 01842 002 REV A*
>>
>> *16 HEX 16 30 31 ENTREX INC 62 00 01842 002 REV A**
>> 15 OPTION 2 Empty**
>> 14 OPTION 1 Empty**
>> 13 PRINTER ENTREX INC SN598**
>> 12 TAPE 556/800 BPI 2433 LFI 213**
>> 11 TAPE 1600 BPI Empty**
>> 10 DISK 2456 00 MP-Kontroller D44an620
>> 6393500215 2456 7 0 1577**
>> 09 COMMO Empty**
>> 08 SCANNER Scanner BD 2431 NCAG 54147.1.15 2431
>> 02394**
>> 07 MEM 1609 0 7 02616**
>> 06 MEM Empty**
>> 05 MEM 1609 0 8 02367**
>> 04 MEM 1615 01 9 5596**
>> 03 TTY Empty**
>> 02 DO NOT USE Empty**
>> 01 C.P. 1509 05 4 04436*
>>
>> Concerning this I also ask a few questions:
>>
>> *
>>
>> What are the boards in slots 16 and 17 for?
>>
>> *
>>
>> I do not have a COM card, does that mean that I could not attempt a
>> serial transmission (type rs232) with this actual setup ?
>>
>> *
>>
>> I have no idea how many kilobytes are present, apparently there are
>> two core memory cards (8kb each? 16Kb each?), And non-core RAM board.
>>
>> I first solved a problem with the power supply of the disk pack (bad HF
>> filter, short-circuited with the chassis, then it is also dead HF filter in
>> the "multi-plug" of the chassis that start to burn, once these problems
>> were solved, I cleaned the machine thoroughly, cleaning the heads of
>> readings with isopropyl alcohol, I Not yet cleaned the disc himself which
>> at first glance looks extremely clean, it has not left the machine for 30
>> years.
>>
>> http://www.actingmachines.com/classiccmp_forum/disckpack01.jpg <
>> http://www.zeltrax.com/classiccmp_forum/disckpack01.jpg>
>>
>> I cleaned all the guides and the heads of the nine track tape Pertec
>> 8840A. There was also a false contact in the ON-LINE button. I did a first
>> cleanup. I think there is always a problem with the HI-DEN button used to
>> set the magtape to 800BPI. It is currently ineffective, but I have a doubt
>> about the contacts of the lamp socket).
>>
>> http://www.actingmachines.com/classiccmp_forum/ninetrack.jpg <
>> http://www.zeltrax.com/classiccmp_forum/ninetrack.jpg>
>>
>> I then cleaned all the sockets and contacts at the boards of the computer
>> (logic and PSU)
>>
>> http://www.actingmachines.com/classiccmp_forum/clean_contact.jpg <
>> http://www.zeltrax.com/classiccmp_forum/clean_contact.jpg>
>>
>>
>> Unfortunately, after a couple of hours, the "POWER FAIL" light has
>> started to light up. The problem here is that I have no schematics, it is a
>> modular power supply consisting of two elements:
>>
>> http://www.actingmachines.com/classiccmp_forum/psus.jpg <
>> http://www.zeltrax.com/classiccmp_forum/psus.jpg>
>>
>> One seems to be dedicated to the 15 VDC regulated, the second module is
>> in charge of the regulated 5VDC. Both elements have a "Power fail module".
>> When the machine is completely populated I now observe that the + 5VDC
>> collapses at +1,9VDC.
>>
>> Here what I measured out, you will also see what the boards of these
>> power supply look like.
>>
>> http://www.actingmachines.com/classiccmp_forum/psu_module_1.jpg <
>> http://www.zeltrax.com/classiccmp_forum/psu_module_1.jpg>
>>
>> http://www.actingmachines.com/classiccmp_forum/psu_module_2.jpg <
>> http://www.zeltrax.com/classiccmp_forum/psu_module_2.jpg>
>>
>> Another thing I noted during my measurements, where I should (I think)
>> measure 15V, I have 18V, looking at the documentation on the NOVA 2 (4
>> slots), I observed according to the diagrams below That there is 18V but
>> before a zener diode and not at the level of connectors where there must be
>> 15VDC, should I warn me ? Would the diode be dead ?
>>
>> I tried to join temporarily a secondary regulated power supply to
>> reinforce the + 5VDC so as to be sure that the problem did not come from
>> the logical part of the computer which checks these voltages and triggers
>> the Power Fail status. By coupling this external regulated power supply,
>> the computer restarts again, thus it is definitively the power supply (or
>> the comparator component(s) of the power fail module)
>>
>> If I removes all the boards (printer, core memory, scanner, disk
>> controller, etc.), the Power Fail light eventually goes out, I get again
>> the 5VDC, so the power has become "too weak" to power the computer when it
>> is fully populated.
>>
>> Despite the temporary (and dangerous) look of my assembly with secondary
>> power supply, I could not stop myself and attempt a boot procedure via the
>> Cold Start button of the machine from the Disk Pack, and it works! :-)
>>
>> http://www.zeltrax.com/classiccmp_forum/first_boot.jpg
>>
>> It seems that I still have problems with the magtape, I had errors trying
>> to read a backup, but it may be simply because I still cannot get the
>> machine in 800BPI because of the capricious buttons of the front panel. I
>> also wrote a tape mark via a "WRITE TAPE MARK AND REWIND" function, the
>> mark seems to be written but does not do the Rewind, however if I launch a
>> REWIND only function, it executes the action appropriately. In short, still
>> things to investigate on this side.
>>
>> Notes that the Operating system I used to make these tests is a very
>> limited OS named DIDOS which was distributed by Nixdorf for his 620 Serie.
>> As the machine is a clone of DG NOVA 2/10, I wonder if the computer is
>> compatible with programs for the NOVA series of Data General? So I wonder
>> if the DCC-116 was compatible with the software for NOVAs?
>>
>> The other questions I ask myself at this point are the ways to transfer
>> softwares or bootable OS on this machine? I have no other disk pack on
>> another system but I have a nine track tape TU81 + connected to a VAX
>> 4000-605A under OpenVMS 6.2, and I can put this computer on my network. Do
>> you think there's a way to make a bootable tape for my NOVA 2 clone with
>> the Pertec 8840A from a VAX 4000 with a TU81+ ?
>>
>> Well, to continue, I have to repair this PSU, all information is welcome,
>> schematics would be ideal of course.
>>
>> Finally, note that I am not a professional electronics technician, I
>> fixed a lot of machines basic knowledge, intuition, researches, comparisons
>> and logic, it is effective but full of limitations too, so forgive me in
>> advance If I do not always understand the possible answers of electronics
>> in "high engineering" mode ;-)
>>
>> As a bonus, the V1 of a small video mounted with a few clips captured
>> during a session of my nocturnal repairs, during the first boot of the
>> machine since 3 decades ! (on my music, yes, I'm also a composer ;-) )
>>
>> https://youtu.be/5jWOUtLKRIU
>>
>> Thanks a lot to all in advance ;-)
>>
>> Dominique
>>
>>
>
>
> --
>
> Thanks,
> AJ Palmgren
> http://fb.me/SelmaTrainWreck
> https://www.facebook.com/profile.php?id=100010931314283
> https://www.linkedin.com/in/aj-palmgren-4a085516/
>
>
--
Thanks,
AJ Palmgren
http://fb.me/SelmaTrainWreck
https://www.facebook.com/profile.php?id=100010931314283
https://www.linkedin.com/in/aj-palmgren-4a085516/
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