DCC-116 E / DATA GENERAL NOVA 2/10 / Nixdorf 620 - Restoring and restarting

Wed May 17 22:29:54 CDT 2017

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/