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@classiccmp.org <mailto:cctalk@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.actingmachines.com/classiccmp_forum/overview01.jpg>
<http://www.zeltrax.com/classiccmp_forum/overview01.jpg
<http://www.zeltrax.com/classiccmp_forum/overview01.jpg>>
http://www.actingmachines.com/classiccmp_forum/terminal.jpg
<http://www.actingmachines.com/classiccmp_forum/terminal.jpg>
<http://www.zeltrax.com/classiccmp_forum/terminal.jpg
<http://www.zeltrax.com/classiccmp_forum/terminal.jpg>>
http://www.actingmachines.com/classiccmp_forum/comrack_closeup.jpg
<http://www.actingmachines.com/classiccmp_forum/comrack_closeup.jpg>
<http://www.zeltrax.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.actingmachines.com/classiccmp_forum/DCC.jpg>
<http://www.zeltrax.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 <tel: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.actingmachines.com/classiccmp_forum/disckpack01.jpg>
<http://www.zeltrax.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.actingmachines.com/classiccmp_forum/ninetrack.jpg>
<http://www.zeltrax.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.actingmachines.com/classiccmp_forum/clean_contact.jpg>
<http://www.zeltrax.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.actingmachines.com/classiccmp_forum/psus.jpg>
<http://www.zeltrax.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.actingmachines.com/classiccmp_forum/psu_module_1.jpg>
<http://www.zeltrax.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.actingmachines.com/classiccmp_forum/psu_module_2.jpg>
<http://www.zeltrax.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
<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/
