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

2017-08-30 Thread Curious Marc via cctalk 
Awesome! Congratulations!
Marc

> From: Dominique Carlier <d...@skynet.be>
> Date: Tuesday, August 29, 2017 
> Subject: Re: DCC-116 E / DATA GENERAL NOVA 2/10 / Nixdorf 620 - Restoring and 
> restarting
> YES! The monster booting again! :-)

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

2017-08-29 Thread Torfinn Ingolfsen via cctalk 
On Tue, Aug 29, 2017 at 10:44 PM, Dominique Carlier via cctalk
 wrote:
> YES! The monster booting again! :-)

Congratulations! Well done!
Thanks for sharing the story and the pictures.
-- 
Regards,
Torfinn Ingolfsen

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

2017-08-29 Thread Dominique Carlier via cctalk 

YES! The monster booting again! :-)

Thus after checking the condition of the capacitors and the rectifying 
diodes by interchanging the 5v sources under the advice of Curious Marc, 
a finally swapped Q12 and Q13, find the dead one, replace Q13. Following 
the advice of Christian I raised both regulated + 5V by taking into 
account the resistance of the circuit. It was a good advice because in 
full load, it was missing something like 0.3V.


Finally I was for sure with a machine that would running but not booting.

As I suspected a problem with the OS installed in the core memory and on 
the Diablo 44 I tried in vain to reinstall this OS (Didos) from tape 
drive, unsuccessfully. To spice things up ,the machine fall in 
protection because of an overheating in the power supply G1.
I open for the 20th time these two PSU, to find that the fan of G1 is 
dead, I tried to repair it but the coil is downright grilled. It's good 
news. I find another fan, I do not have a 115VAC in stock , I solder new 
wires to feed 220VAC to the "new" fan. Problem solved !


http://www.zeltrax.com/classiccmp_forum/second_boot/00a.jpg
http://www.zeltrax.com/classiccmp_forum/second_boot/00b.jpg

And now let's go to find the problem on the Pertec tape drive side, 
engine control works, it's like if it reading/receive nothing,  I 
cleaning the read head again, connectors (read, write, control), I 
linger on the front buttons and bingo! The lamp of the switch 500/800 
BPI stays lit regardless of the real state, thus I was trying to read 
800 bpi tape under 500 bpi modewithout knowing. Small but vicious failure.


After that I was able to install from the master tape a new version of 
this OS, YES ! I reformatted the Diablo disk, I made read tests, writing 
with various devices, all seems OK!!

I'm happy, this machine comes back from afar ;-)

I have five Entrex terminals but I will already take care of the one 
currently active, it must be cleaned from top to bottom. The plastic of 
the hull is yellowed by the years, I think I will not have fun to do 
retrobright, I will squarely repaint it. The keyboard works well but 
some touch contacts are a bit recalcitrant. About the printer there is 
work, I will rather concentrate about the Operating System because here, 
besides the small happening aesthetic that I allow myself to do now, it 
is imperative that I find an Operating System, a real OS and even several.


The stuff currently installed is very basic, extremely closed, hyper 
limited, for my part this OS does not even deserve the name of OS, it is 
a simple data acquisition software with some abstruse utilities, DIDOS 
was Developed by Nixdorf for its "own" model 620, a D-116 (17 slots) 
made up of Digital Computer Control (itself being a clone of Nova 1200).
As I describe in other posts, the CPU seems to have been upgraded since 
it dates from 1978 while some maintenance control stickers date from 
1976, another on a multiplexing card for terminals Entrex displays 1974.


I'm going on the idea of ​​finding RDOS for the 16-bit Nova line, but 
maybe I could install a newer OS (eg AOS for the 16-bit Eclipse)? I also 
read many pages on which it was also a question of DG-DOS, RTOS, NIROS 
 know you others?


In any case one thing is sure: I searched for hours and I did not find 
anything to make a new op-sys tape to install something else instead of 
my pathetic Didos. The only downloadable data I found, some RDOS sources 
for SIMH which emulates the DG NOVA. Do any of you know where I might 
find these precious data?

Of course I also look for a maximum of programs to install on the monster.

For info I have a VAX 4000-605A with a TU81 + (currently disconnected) 
but which would allow me to write a tape with data transiting thru my 
home network.
Otherwise I also have a Shugart (KENNEDY) 9612 which can write in 800, 
1600, 3200 or 6250 bpi, this tape drive is equipped with a SCSI interface.


https://computerarchive.org/files/comp/hardware/Shugart%20Kennedy%209-track%209610%20tape%20drives.pdf

I have not analyzed if I can connect it directly to a good old Adaptec 
controller inside a PC, nor with which program I could exploit it.

Besides if you have information about this they are welcome!

And finally,  while waiting for the video, here some pictures of the 
machine in operation ;-)


http://www.zeltrax.com/classiccmp_forum/second_boot/01.jpg

http://www.zeltrax.com/classiccmp_forum/second_boot/02.jpg

http://www.zeltrax.com/classiccmp_forum/second_boot/03.jpg

http://www.zeltrax.com/classiccmp_forum/second_boot/04.jpg

Dominique

PS: AJ, some pics of the Entrex terminal for you above ;-)

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

2017-08-28 Thread Christian Corti via cctalk 

On Sat, 26 Aug 2017, Dominique Carlier wrote:
I have temporarily replaced the 2N6471 by an approaching equivalent, I makes 
the settings to get very exactly + 5V on both outputs and the machine 
restarted, finally! YES !! :-)

[...]
then 02, 03 !! 04 !!! 05 !! And then ... nothing, and since it got worse, 
it did not pass the stage 02. Now it crashes from the beginning, nothing on 
the screen. Is my disk pack damaged? :-/


Please measure the voltages on the boards (like pin 14 of some standard 
TTL IC). Usually there's a non-negligible voltage drop between the PS 
output and the logic caused by the inevitable resistance of the 
connectors. It is entirely possible that the disk controller behaves 
erratically when powered with e.g. 4.7V instead of 5V.


Christian

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

2017-08-27 Thread AJ Palmgren via cctalk 
Dominique, I just want to say how impressed I am with your work here, as
well as the way you're documenting it.  This is fantastic stuff!

There's a lot of emails on this thread for me to catch up on from the past
month.  But if I have one request, it's that you post any additional pics
you might have on the Entrex terminal.  This is what has really drawn me
into this chapter of your project.

Keep up the great work!

-AJ

http://Entrex480.blogspot.com  (badly in need of updating)

http://Point4iris.com


On Sat, Aug 19, 2017 at 12:50 PM, Curious Marc via cctalk <
cctalk@classiccmp.org> wrote:

> A straightforward linear supply. We should be able to get that puppy
> working. Looks like you have two of the same thing on G2, two +5V supplies.
> You could take advantage of that and compare voltages of one against the
> other at several points. You coukd also monitor the voltage on the non
> regulated side of the power transistors, if that crashes too, it's more
> likely it's a problem in the caps or the rectifier diodes. If it crashes
> after, transistors or regulation circuit could be suspect. Maybe we can do
> a Skype "en Francais"  and debug it together.
> Marc
>
>
> On Aug 19, 2017, at 12:10 PM, Dominique Carlier via cctalk <
> cctalk@classiccmp.org> wrote:
>
> Maybe it's better to give us all the useful information these power
> supplies, moreover it might be useful to other people with the same
> computer.
>
> An overall bloc diagram of the D-116 power supply including G1 and G2.
> http://www.zeltrax.com/classiccmp_forum/psu_overall_bloc_diagram.jpg
>
> The complete schematics of the part of the power supply named G2.
> http://www.zeltrax.com/classiccmp_forum/g2_schematics.jpg
>
> A drawing of the regulation board of the power supply G2 with the physical
> locations of the components.
> http://www.zeltrax.com/classiccmp_forum/g2_regulator_board.jpg
>
> The schematics of this regulation board.
> http://www.zeltrax.com/classiccmp_forum/g2_regulator_board_schematics.jpg
>
> And a bit of literature concerning the principle of operation about the
> regulation with this PSU (you will understand better why I am a little bit
> lost ;-) This principle of regulation with a panoply of verification and
> Protection systems everywhere is unusual for me)
> http://www.zeltrax.com/classiccmp_forum/psu_regulation_principe.jpg
>
> I have already tried without the CPU board: same symptoms. Next step, try
> to check the capacitors in operation.
>
> And because all this is a little bit boring, here is, as a small gift, a
> photo gallery of the machine under different angles ;-)
>
> Ensemble
>
> http://www.zeltrax.com/classiccmp_forum/serie01/ensemble_01.jpg
> http://www.zeltrax.com/classiccmp_forum/serie01/ensemble_02.jpg <
> http://www.zeltrax.com/classiccmp_forum/serie01/ensemble_02.jpg>
>
> D-116 Front panel
>
> http://www.zeltrax.com/classiccmp_forum/serie01/d116_front_panel_01.jpg
> http://www.zeltrax.com/classiccmp_forum/serie01/d116_front_panel_02.jpg
> http://www.zeltrax.com/classiccmp_forum/serie01/d116_front_panel_03.jpg
>
> D-116 open rack
>
> http://www.zeltrax.com/classiccmp_forum/serie01/d116_open_01.jpg
> http://www.zeltrax.com/classiccmp_forum/serie01/d116_open_02.jpg
>
> G2 regulator board
>
> http://www.zeltrax.com/classiccmp_forum/serie01/g2_regulator_board.jpg
>
> Disk Pack drive Diablo Model 40
>
> http://www.zeltrax.com/classiccmp_forum/serie01/diskpack_drive_01.jpg
> http://www.zeltrax.com/classiccmp_forum/serie01/diskpack_drive_02.jpg
> http://www.zeltrax.com/classiccmp_forum/serie01/diskpack_drive_03.jpg
>
> Mag-tape Pertec 8840A
>
> http://www.zeltrax.com/classiccmp_forum/serie01/pertec_close.jpg
> http://www.zeltrax.com/classiccmp_forum/serie01/pertec_open_01.jpg
> http://www.zeltrax.com/classiccmp_forum/serie01/pertec_open_02.jpg
> http://www.zeltrax.com/classiccmp_forum/serie01/pertec_open_03.jpg
> http://www.zeltrax.com/classiccmp_forum/serie01/pertec_open_04.jpg
> http://www.zeltrax.com/classiccmp_forum/serie01/pertec_open_05.jpg
>
> Drum printer Data Products model 2230
>
> http://www.zeltrax.com/classiccmp_forum/serie01/printer_01.jpg
> http://www.zeltrax.com/classiccmp_forum/serie01/printer_02.jpg
> http://www.zeltrax.com/classiccmp_forum/serie01/printer_03.jpg
>
> Terminal Entrex
>
> http://www.zeltrax.com/classiccmp_forum/serie01/terminal.jpg
> http://www.zeltrax.com/classiccmp_forum/serie01/terminal_nacked.jpg
>
> Rear panel / connectors
>
> http://www.zeltrax.com/classiccmp_forum/serie01/rear_panel.jpg
>
> From inside
>
> http://www.zeltrax.com/classiccmp_forum/serie01/flat_cables.jpg
> http://www.zeltrax.com/classiccmp_forum/serie01/from_inside.jpg <
> http://www.zeltrax.com/classiccmp_forum/serie01/from_inside.jpg>
>
> Haa I can't wait to operate this heavy machine! ;-)
>
> Dominique
>
>
>

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

2017-08-25 Thread Dominique Carlier via cctalk 
er.
The POWER FAIL sensing is not symmetric between the two regulators, they may 
have swapped the supplies so the sensing followed with the big-IO boards.
Or the documentation may just be incorrect.

Alternatively, the supplies do share the tertiary +34V supply (and the 
transformer input), but interaction here seems less likely (not to rule 
anything out).

This regulator-to-slots wiring should be sorted out/confirmed with some 
checking.

The theory-of-op page you supplied from the manual mentions a paragraph 6-3 
that may describe the power fail circuit, but it's not on that page.
As you mentioned way back that the power fail was being asserted, it might be 
helpful to see that paragraph.


 From earlier:

A minor comment regarding the components in the power supply: Q13 is a stage in 
the regulator drivers and as consequential as other components such as Q2.

Do you think that Q12 (linked to defective A1 / + 5v) could be the culprit?

Yes, it could be.
If that transistor were open/faulty, the pass transistors would still be 
getting some drive current through the BE resistor and perhaps the BE junction 
but not getting the current gain the transistor is supposed to provide.
At low load current, the output V would be fine as the drive is adequate to 
maintain control of the pass transistors, but as the load current increases the 
pass transistors would saturate (not be able to pass more current) relative to 
the (now inadequate) drive current, and the output voltage would drop.
Bipolar transistors are current amplifiers, there is a direct limiting relation 
between the drive current through the base and what can be drawn through the 
collector.

Of course, whether it is the culprit is another question.
You could do simple junction tests on it.

  A more analytical approach would be a good idea to broadly sort out the fault 
area:
1. the input/raw supply.
- low average voltage taking the input V below the 
dropout / headroom level for the regulator,
- excessive ripple taking the input V below the dropout 
level.

2. the regulator.
- loss of gain,
- unduly going into current limiting.

3. faulty load(s) sending the supply into (designed) current 
limiting.

Now that we know something about the power distribution, 3 seems less likely.

Marc's tests would be very helpful.





On 25/08/2017 06:43, Curious Marc wrote:

Dominique,
I wouldn't worry about the readings on your 0.1 Ohm resistor, you are not going 
to get any trustable results on something that low without a four wire 
ohm-meter.
It seems that you have eliminated the power transistors as being the source of 
the failure.
I'd like to eliminate the rectifier diodes or the big caps as the source of the 
problem
1-Could you please measure and compare (or better get a scope trace) of 
the voltage at the F3 and F2 fuses when the voltage drops. If the voltage also 
drops at the fuse (pre-regulation) then either your caps/diode combo is not 
good, or your boards are drawing too much current.
2-   If that's the case, you could also easily swap the power source for 
the two regulators. Temporarily lifting both fuses on the output side , and 
cross wire F2 to feed A2 and F3 to feed A1. If the fault moves, that would 
strongly  indicate that one of the cap/diode combo is bad. If it does not, then 
either the regulation circuitry is bad or the boards draw an anomalous amount 
of power.
3-   Measure how much each board is pulling (as far as amps). You can do 
this easily by removing the fuse and putting an ammeter in its place, then plug 
each board one at a time, and read what the amperage is.
4-   Do a similar measurement adding boards one by one and see at which 
amperage the voltage starts to degrade, and if it exceeds the design criterion 
for the power supply.
Marc
  
From: cctalk <cctalk-boun...@classiccmp.org> on behalf of "cctalk@classiccmp.org" <cctalk@classiccmp.org>

Reply-To: Dominique Carlier <d...@skynet.be>, "cctalk@classiccmp.org" 
<cctalk@classiccmp.org>
Date: Wednesday, August 23, 2017 at 6:17 AM
To: "cctalk@classiccmp.org" <cctalk@classiccmp.org>
Subject: Re: DCC-116 E / DATA GENERAL NOVA 2/10 / Nixdorf 620 - Restoring and 
restarting
  
Here is the situation.
  
The + 5V 12A that collapses comes out from pins 10-14 / 36-40, the other

+ 5V 12A (pins 15-22 / 36-40) never goes down.
  
All that I surrounded in green on that image (1950×2361, zoomable) are

the components that I tested on the power supply G2, A3 motherboard,
regulation board and heatsink A1 + A2:
http://www.zeltrax.com/classiccmp_forum/psu_g2_test/g2_tested_components.jpg
  
To eliminate some doubts and because I do not have some spare parts on

hand, I switched the modules A1 and A2, same result. Idem with the
transistors 2N2905, same result.
The result is alway

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

2017-08-25 Thread Dominique Carlier via cctalk 

Hi all,

Thank you Marc, I will follow your advice. Doubts must be removed. I 
would be glad to know that the big (and expensive) capacitors are OK.


In the meantime I have new information. Following the remarks of Brent 
Hilpert I sought to have more information on the backplane of my D116-E. 
I always assumed that the information in the manuals did not match my 
version of backplane because of this:

http://www.zeltrax.com/classiccmp_forum/backplane/01.jpg

The boards are placed to another slots in the documentation. I put this 
on the accounts of the many revisions but also the fact that the 
computer has been distributed by Nixdorf and they probably assembled the 
elements, and made the setup of the backplane with the wires. Regardless 
of the configuration of the slots, the wires setup, the associated 
external connectors, at the level of power supply finally I thinks that 
should be the same situation on my D116 as on another.
In digging into the second manual which does not contain the schematics 
I found this precious diagram:

http://www.zeltrax.com/classiccmp_forum/backplane/diagram.jpg

I discovered that the common point that brings together the boards 
causing the Power Fail (HDD controller / Tape controller / Scanner) is 
the fact that they are in the slots from 8 to 12 which are powered by 
the regulated +5V of the circuit A2.

http://www.zeltrax.com/classiccmp_forum/backplane/diagram2.jpg

In other words, the circuit + 5V A2 of the power supply G2 serves only 
to power the boards in the slots from 8 to 12 which cause a power fail 
if only one of these slots is populated with one of the boards.


What I don't understood yet is why it's on the pins of A1 (10-14 / 
36-40) that I measure a drop of tension?

http://www.zeltrax.com/classiccmp_forum/backplane/pins_a1.jpg

Because A2 is on the pins 15-22 / 41-48
http://www.zeltrax.com/classiccmp_forum/backplane/diagram_a2.jpg

I will re-read the operation of the Power Fail, maybe it supposed to 
clamp A1 even in case of problem on A2 ?
Or I don't understood all the intricacies about the power supply of 
these antique boards ^^


Anyway I'll do the tests you suggest Marc, it sounds good to have 
confirmation that the basic level are working well before going any further.


Thank you for your help ;-)

Dominique

On 25/08/2017 06:43, Curious Marc wrote:


Dominique,

I wouldn't worry about the readings on your 0.1 Ohm resistor, you are 
not going to get any trustable results on something that low without a 
four wire ohm-meter.


It seems that you have eliminated the power transistors as being the 
source of the failure.


I'd like to eliminate the rectifier diodes or the big caps as the 
source of the problem


1- Could you please measure and compare (or better get a scope trace) 
of the voltage at the F3 and F2 fuses when the voltage drops. If the 
voltage also drops at the fuse (pre-regulation) then either your 
caps/diode combo is not good, or your boards are drawing too much current.


2-If that's the case, you could also easily swap the power source for 
the two regulators. Temporarily lifting both fuses on the output side 
, and cross wire F2 to feed A2 and F3 to feed A1. If the fault moves, 
that would strongly  indicate that one of the cap/diode combo is bad. 
If it does not, then either the regulation circuitry is bad or the 
boards draw an anomalous amount of power.


3-Measure how much each board is pulling (as far as amps). You can do 
this easily by removing the fuse and putting an ammeter in its place, 
then plug each board one at a time, and read what the amperage is.


4-Do a similar measurement adding boards one by one and see at which 
amperage the voltage starts to degrade, and if it exceeds the design 
criterion for the power supply.


Marc

*From: *cctalk <cctalk-boun...@classiccmp.org> on behalf of 
"cctalk@classiccmp.org" <cctalk@classiccmp.org>
*Reply-To: *Dominique Carlier <d...@skynet.be>, "cctalk@classiccmp.org" 
<cctalk@classiccmp.org>

*Date: *Wednesday, August 23, 2017 at 6:17 AM
*To: *"cctalk@classiccmp.org" <cctalk@classiccmp.org>
*Subject: *Re: DCC-116 E / DATA GENERAL NOVA 2/10 / Nixdorf 620 - 
Restoring and restarting


Here is the situation.

The + 5V 12A that collapses comes out from pins 10-14 / 36-40, the other

+ 5V 12A (pins 15-22 / 36-40) never goes down.

All that I surrounded in green on that image (1950×2361, zoomable) are

the components that I tested on the power supply G2, A3 motherboard,

regulation board and heatsink A1 + A2:

http://www.zeltrax.com/classiccmp_forum/psu_g2_test/g2_tested_components.jpg

To eliminate some doubts and because I do not have some spare parts on

hand, I switched the modules A1 and A2, same result. Idem with the

transistors 2N2905, same result.

The result is always the same : it's always the +5V on pins 10-14 /

36-40 that collapses, never the other output.

Some resistors are not yet tested is because

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

2017-08-25 Thread Dominique Carlier via cctalk 

Hi all,

Thank you Marc, I will follow your advice. Doubts must be removed. I 
would be glad to know that the big (and expensive) capacitors are OK.


In the meantime I have new information. Following the remarks of Brent 
Hilpert I sought to have more information on the backplane of my D116-E. 
I always assumed that the information in the manuals did not match my 
version of backplane because of this:

http://www.zeltrax.com/classiccmp_forum/backplane/01.jpg

The boards are placed to another slots in the documentation. I put this 
on the accounts of the many revisions but also the fact that the 
computer has been distributed by Nixdorf and they probably assembled the 
elements, and made the setup of the backplane with the wires. Regardless 
of the configuration of the slots, the wires setup, the associated 
external connectors, at the level of power supply finally I thinks that 
should be the same situation on my D116 as on another.
In digging into the second manual which does not contain the schematics 
I found this precious diagram:

http://www.zeltrax.com/classiccmp_forum/backplane/diagram.jpg

I discovered that the common point that brings together the boards 
causing the Power Fail (HDD controller / Tape controller / Scanner) is 
the fact that they are in the slots from 8 to 12 which are powered by 
the regulated +5V of the circuit A2.

http://www.zeltrax.com/classiccmp_forum/backplane/diagram2.jpg

In other words, the circuit + 5V A2 of the power supply G2 serves only 
to power the boards in the slots from 8 to 12 which cause a power fail 
if only one of these slots is populated with one of the boards.


What I don't understood yet is why it's on the pins of A1 (10-14 / 
36-40) that I measure a drop of tension?

http://www.zeltrax.com/classiccmp_forum/backplane/pins_a1.jpg

Because A2 is on the pins 15-22 / 41-48
http://www.zeltrax.com/classiccmp_forum/backplane/diagram_a2.jpg

I will re-read the operation of the Power Fail, maybe it supposed to 
clamp A1 even in case of problem on A2 ?
Or I don't understood all the intricacies about the power supply of 
these antique boards ^^


Anyway I'll do the tests you suggest Marc, it sounds good to have 
confirmation that the basic level are working well before going any further.


Thank you for your help ;-)

Dominique


On 25/08/2017 06:43, Curious Marc wrote:


Dominique,

I wouldn't worry about the readings on your 0.1 Ohm resistor, you are 
not going to get any trustable results on something that low without a 
four wire ohm-meter.


It seems that you have eliminated the power transistors as being the 
source of the failure.


I'd like to eliminate the rectifier diodes or the big caps as the 
source of the problem


1- Could you please measure and compare (or better get a scope trace) 
of the voltage at the F3 and F2 fuses when the voltage drops. If the 
voltage also drops at the fuse (pre-regulation) then either your 
caps/diode combo is not good, or your boards are drawing too much current.


2-If that's the case, you could also easily swap the power source for 
the two regulators. Temporarily lifting both fuses on the output side 
, and cross wire F2 to feed A2 and F3 to feed A1. If the fault moves, 
that would strongly  indicate that one of the cap/diode combo is bad. 
If it does not, then either the regulation circuitry is bad or the 
boards draw an anomalous amount of power.


3-Measure how much each board is pulling (as far as amps). You can do 
this easily by removing the fuse and putting an ammeter in its place, 
then plug each board one at a time, and read what the amperage is.


4-Do a similar measurement adding boards one by one and see at which 
amperage the voltage starts to degrade, and if it exceeds the design 
criterion for the power supply.


Marc

*From: *cctalk <cctalk-boun...@classiccmp.org> on behalf of 
"cctalk@classiccmp.org" <cctalk@classiccmp.org>
*Reply-To: *Dominique Carlier <d...@skynet.be>, "cctalk@classiccmp.org" 
<cctalk@classiccmp.org>

*Date: *Wednesday, August 23, 2017 at 6:17 AM
*To: *"cctalk@classiccmp.org" <cctalk@classiccmp.org>
*Subject: *Re: DCC-116 E / DATA GENERAL NOVA 2/10 / Nixdorf 620 - 
Restoring and restarting


Here is the situation.

The + 5V 12A that collapses comes out from pins 10-14 / 36-40, the other

+ 5V 12A (pins 15-22 / 36-40) never goes down.

All that I surrounded in green on that image (1950×2361, zoomable) are

the components that I tested on the power supply G2, A3 motherboard,

regulation board and heatsink A1 + A2:

http://www.zeltrax.com/classiccmp_forum/psu_g2_test/g2_tested_components.jpg

To eliminate some doubts and because I do not have some spare parts on

hand, I switched the modules A1 and A2, same result. Idem with the

transistors 2N2905, same result.

The result is always the same : it's always the +5V on pins 10-14 /

36-40 that collapses, never the other output.

Some resistors are not yet tested is because

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

2017-08-25 Thread Dominique Carlier via cctalk 

Hi all,

Thank you Marc, I will follow your advice. Doubts must be removed. I 
would be glad to know that the big (and expensive) capacitors are OK.


In the meantime I have new information. Following the remarks of Brent 
Hilpert I sought to have more information on the backplane of my D116-E. 
I always assumed that the information in the manuals did not match my 
version of backplane because of this:

http://www.zeltrax.com/classiccmp_forum/backplane/01.jpg

The boards are placed to another slots in the documentation. I put this 
on the accounts of the many revisions but also the fact that the 
computer has been distributed by Nixdorf and they probably assembled the 
elements, and made the setup of the backplane with the wires. Regardless 
of the configuration of the slots, the wires setup, the associated 
external connectors, at the level of power supply finally I thinks that 
should be the same situation on my D116 as on another.
In digging into the second manual which does not contain the schematics 
I found this precious diagram:

http://www.zeltrax.com/classiccmp_forum/backplane/diagram.jpg

I discovered that the common point that brings together the boards 
causing the Power Fail (HDD controller / Tape controller / Scanner) is 
the fact that they are in the slots from 8 to 12 which are powered by 
the regulated +5V of the circuit A2.

http://www.zeltrax.com/classiccmp_forum/backplane/diagram2.jpg

In other words, the circuit + 5V A2 of the power supply G2 serves only 
to power the boards in the slots from 8 to 12 which cause a power fail 
if only one of these slots is populated with one of the boards.


What I don't understood yet is why it's on the pins of A1 (10-14 / 
36-40) that I measure a drop of tension?

http://www.zeltrax.com/classiccmp_forum/backplane/pins_a1.jpg

Because A2 is on the pins 15-22 / 41-48
http://www.zeltrax.com/classiccmp_forum/backplane/diagram_a2.jpg

I will re-read the operation of the Power Fail, maybe it supposed to 
clamp A1 even in case of problem on A2 ?
Or I don't understood all the intricacies about the power supply of 
these antique boards ^^


Anyway I'll do the tests you suggest Marc, it sounds good to have 
confirmation that the basic level are working well before going any further.


Thank you for your help ;-)

Dominique

(PS: Sorry for duplicate messages, I had to go wrong with the reply 
addresses so that it appears on the forum)





On 25/08/2017 06:43, Curious Marc wrote:


Dominique,

I wouldn't worry about the readings on your 0.1 Ohm resistor, you are 
not going to get any trustable results on something that low without 
a four wire ohm-meter.


It seems that you have eliminated the power transistors as being the 
source of the failure.


I'd like to eliminate the rectifier diodes or the big caps as the 
source of the problem


1- Could you please measure and compare (or better get a scope trace) 
of the voltage at the F3 and F2 fuses when the voltage drops. If the 
voltage also drops at the fuse (pre-regulation) then either your 
caps/diode combo is not good, or your boards are drawing too much 
current.


2-If that's the case, you could also easily swap the power source for 
the two regulators. Temporarily lifting both fuses on the output side 
, and cross wire F2 to feed A2 and F3 to feed A1. If the fault moves, 
that would strongly  indicate that one of the cap/diode combo is bad. 
If it does not, then either the regulation circuitry is bad or the 
boards draw an anomalous amount of power.


3-Measure how much each board is pulling (as far as amps). You can do 
this easily by removing the fuse and putting an ammeter in its place, 
then plug each board one at a time, and read what the amperage is.


4-Do a similar measurement adding boards one by one and see at which 
amperage the voltage starts to degrade, and if it exceeds the design 
criterion for the power supply.


Marc


Here is the situation.

The + 5V 12A that collapses comes out from pins 10-14 / 36-40, the other

+ 5V 12A (pins 15-22 / 36-40) never goes down.

All that I surrounded in green on that image (1950×2361, zoomable) are

the components that I tested on the power supply G2, A3 motherboard,

regulation board and heatsink A1 + A2:

http://www.zeltrax.com/classiccmp_forum/psu_g2_test/g2_tested_components.jpg

To eliminate some doubts and because I do not have some spare parts on

hand, I switched the modules A1 and A2, same result. Idem with the

transistors 2N2905, same result.

The result is always the same : it's always the +5V on pins 10-14 /

36-40 that collapses, never the other output.

Some resistors are not yet tested is because these must be de-soldered

for a valid test, but the printed circuit is very fragile and many

component have legs bent into the weld.

Except for the not tested components (among others the LM376, the

rectifier diodes) At this stage I start again to suspect a little

everything. The famous large capacitors of the power supply (C1 to C4).

But

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

2017-08-25 Thread Curious Marc via cctalk 
Dominique,

I wouldn't worry about the readings on your 0.1 Ohm resistor, you are not going 
to get any trustable results on something that low without a four wire 
ohm-meter. 

It seems that you have eliminated the power transistors as being the source of 
the failure.

I'd like to eliminate the rectifier diodes or the big caps as the source of the 
problem

1-    Could you please measure and compare (or better get a scope trace) of 
the voltage at the F3 and F2 fuses when the voltage drops. If the voltage also 
drops at the fuse (pre-regulation) then either your caps/diode combo is not 
good, or your boards are drawing too much current.

2-   If that's the case, you could also easily swap the power source for 
the two regulators. Temporarily lifting both fuses on the output side , and 
cross wire F2 to feed A2 and F3 to feed A1. If the fault moves, that would 
strongly  indicate that one of the cap/diode combo is bad. If it does not, then 
either the regulation circuitry is bad or the boards draw an anomalous amount 
of power.

3-   Measure how much each board is pulling (as far as amps). You can do 
this easily by removing the fuse and putting an ammeter in its place, then plug 
each board one at a time, and read what the amperage is.

4-   Do a similar measurement adding boards one by one and see at which 
amperage the voltage starts to degrade, and if it exceeds the design criterion 
for the power supply.

Marc

 

From: cctalk <cctalk-boun...@classiccmp.org> on behalf of 
"cctalk@classiccmp.org" <cctalk@classiccmp.org>
Reply-To: Dominique Carlier <d...@skynet.be>, "cctalk@classiccmp.org" 
<cctalk@classiccmp.org>
Date: Wednesday, August 23, 2017 at 6:17 AM
To: "cctalk@classiccmp.org" <cctalk@classiccmp.org>
Subject: Re: DCC-116 E / DATA GENERAL NOVA 2/10 / Nixdorf 620 - Restoring and 
restarting

 

Here is the situation.

 

The + 5V 12A that collapses comes out from pins 10-14 / 36-40, the other 

+ 5V 12A (pins 15-22 / 36-40) never goes down.

 

All that I surrounded in green on that image (1950×2361, zoomable) are 

the components that I tested on the power supply G2, A3 motherboard, 

regulation board and heatsink A1 + A2:

http://www.zeltrax.com/classiccmp_forum/psu_g2_test/g2_tested_components.jpg

 

To eliminate some doubts and because I do not have some spare parts on 

hand, I switched the modules A1 and A2, same result. Idem with the 

transistors 2N2905, same result.

The result is always the same : it's always the +5V on pins 10-14 / 

36-40 that collapses, never the other output.

 

Some resistors are not yet tested is because these must be de-soldered 

for a valid test, but the printed circuit is very fragile and many 

component have legs bent into the weld.

 

Except for the not tested components (among others the LM376, the 

rectifier diodes) At this stage I start again to suspect a little 

everything. The famous large capacitors of the power supply (C1 to C4). 

But also a possible problems on the boards of the computer itself.

 

As one of you mentioned, the hypothesis of shorted decoupling capacitors 

on the boards could put the power supply in default.

 

Note that the machine runs normally with the CPU board, three core 

memory boards (400w each) + two multiplexing boards for terminals + the 

printer board.

If I add only one of these remaining board:

- Disk Pack Controller

- 9-track tape Controller

- "scanner" board (also for terminals)

 

-> Power Fail.

 

Note that : if I only connect the CPU and the disk pack controller card: 

Power Fail too !!

 

What makes me doubtful about this scenario is that I can not imagine 

that these three boards, each causing the Power Fail, could fail 

simultaneously. Remember that the first time I powered up the beast (one 

big hour), the machine was working with all the boards and Power Fail 

appeared at once.

I have not retested since but also note that by adding an external power 

supply just for the deficient + 5V , the machine has restarted and even 

booted the operating system.

 

If you have another ideas? LM376?

 

Thanks

 

Dominique

 

 

On 20/08/2017 09:08, Brent Hilpert wrote:

On 2017-Aug-19, at 12:10 PM, Dominique Carlier via cctalk wrote:

Maybe it's better to give us all the useful information these power supplies, 
moreover it might be useful to other people with the same computer.

 

An overall bloc diagram of the D-116 power supply including G1 and G2.

http://www.zeltrax.com/classiccmp_forum/psu_overall_bloc_diagram.jpg

 

The complete schematics of the part of the power supply named G2.

http://www.zeltrax.com/classiccmp_forum/g2_schematics.jpg

 

A drawing of the regulation board of the power supply G2 with the physical 
locations of the components.

http://www.zeltrax.com/classiccmp_forum/g2_regulator_board.jpg

 

The schematics of this regulation board.

http://www.zeltrax.com/classiccmp_forum

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

2017-08-25 Thread Brent Hilpert via cctalk 
  - unduly going into current limiting.

3. faulty load(s) sending the supply into (designed) current 
limiting.

Now that we know something about the power distribution, 3 seems less likely.

Marc's tests would be very helpful.




> 
> On 25/08/2017 06:43, Curious Marc wrote:
>> Dominique,
>> I wouldn't worry about the readings on your 0.1 Ohm resistor, you are not 
>> going to get any trustable results on something that low without a four wire 
>> ohm-meter.
>> It seems that you have eliminated the power transistors as being the source 
>> of the failure.
>> I'd like to eliminate the rectifier diodes or the big caps as the source of 
>> the problem
>> 1-Could you please measure and compare (or better get a scope trace) 
>> of the voltage at the F3 and F2 fuses when the voltage drops. If the voltage 
>> also drops at the fuse (pre-regulation) then either your caps/diode combo is 
>> not good, or your boards are drawing too much current.
>> 2-   If that's the case, you could also easily swap the power source for 
>> the two regulators. Temporarily lifting both fuses on the output side , and 
>> cross wire F2 to feed A2 and F3 to feed A1. If the fault moves, that would 
>> strongly  indicate that one of the cap/diode combo is bad. If it does not, 
>> then either the regulation circuitry is bad or the boards draw an anomalous 
>> amount of power.
>> 3-   Measure how much each board is pulling (as far as amps). You can do 
>> this easily by removing the fuse and putting an ammeter in its place, then 
>> plug each board one at a time, and read what the amperage is.
>> 4-   Do a similar measurement adding boards one by one and see at which 
>> amperage the voltage starts to degrade, and if it exceeds the design 
>> criterion for the power supply.
>> Marc
>> 
>> From: cctalk <cctalk-boun...@classiccmp.org> on behalf of 
>> "cctalk@classiccmp.org" <cctalk@classiccmp.org>
>> Reply-To: Dominique Carlier <d...@skynet.be>, "cctalk@classiccmp.org" 
>> <cctalk@classiccmp.org>
>> Date: Wednesday, August 23, 2017 at 6:17 AM
>> To: "cctalk@classiccmp.org" <cctalk@classiccmp.org>
>> Subject: Re: DCC-116 E / DATA GENERAL NOVA 2/10 / Nixdorf 620 - Restoring 
>> and restarting
>> 
>> Here is the situation.
>> 
>> The + 5V 12A that collapses comes out from pins 10-14 / 36-40, the other
>> + 5V 12A (pins 15-22 / 36-40) never goes down.
>> 
>> All that I surrounded in green on that image (1950×2361, zoomable) are
>> the components that I tested on the power supply G2, A3 motherboard,
>> regulation board and heatsink A1 + A2:
>> http://www.zeltrax.com/classiccmp_forum/psu_g2_test/g2_tested_components.jpg
>> 
>> To eliminate some doubts and because I do not have some spare parts on
>> hand, I switched the modules A1 and A2, same result. Idem with the
>> transistors 2N2905, same result.
>> The result is always the same : it's always the +5V on pins 10-14 /
>> 36-40 that collapses, never the other output.
>> 
>> Some resistors are not yet tested is because these must be de-soldered
>> for a valid test, but the printed circuit is very fragile and many
>> component have legs bent into the weld.
>> 
>> Except for the not tested components (among others the LM376, the
>> rectifier diodes) At this stage I start again to suspect a little
>> everything. The famous large capacitors of the power supply (C1 to C4).
>> But also a possible problems on the boards of the computer itself.
>> 
>> As one of you mentioned, the hypothesis of shorted decoupling capacitors
>> on the boards could put the power supply in default.
>> 
>> Note that the machine runs normally with the CPU board, three core
>> memory boards (400w each) + two multiplexing boards for terminals + the
>> printer board.
>> If I add only one of these remaining board:
>> - Disk Pack Controller
>> - 9-track tape Controller
>> - "scanner" board (also for terminals)
>> 
>> -> Power Fail.
>> 
>> Note that : if I only connect the CPU and the disk pack controller card:
>> Power Fail too !!
>> 
>> What makes me doubtful about this scenario is that I can not imagine
>> that these three boards, each causing the Power Fail, could fail
>> simultaneously. Remember that the first time I powered up the beast (one
>> big hour), the machine was working with all the boards and Power Fail
>> appeared at once.
>> I have not retested since but also note that by adding an external power

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

2017-08-23 Thread Dominique Carlier via cctalk 

I put the answers in your message

23/08/2017 20:22, Brent Hilpert via cctalk wrote:


Am I correct in inferring that this machine (the processor) has four +5V 
regulators?:  it appears there are 2 power supply chassis (rear photo), each 
with 2 regulators,
or are those 2 chassis not identical and there are only to two +5 regulators?

I myself have trouble understanding and for good reason:

The power supply Gl provides :

   - unregulated +15V
   - unregulated -15V
   - regulated -5V
   - regulated +15V
   - regulated +5V voltages
   - a 30V peak-to peak voltage
   - a time delayed (sequenced) outputs; MEM OK, +5V OK and Power Fail

The sequenced outputs are such that upon power turn-on, first the +5V OK 
occurs, then MEM OK, followed by Power Fail. Upon power turn-off or when 
input power is lost, first the Power Fail goes low, then MEM OK and then 
+5V OK goes down.


The G2 type Power Supply provides :

   - unregulated +15V
   - unregulated -15V
   - two distinct regulated +5V
   - regulated -5V
   - a 30V peak-to-peak voltage
   - a time delayed Power Fail and +5V OK signals



Either way, is it documented or has it been mapped out how the regulators are 
distributed to the bus/backplane slots?

No

If not, I would suggest doing so to start with, so you know what slots & boards 
each regulator is supplying power to.

I would like to but ... here is the back-plane:

http://www.zeltrax.com/classiccmp_forum/psu_g2_test/backplane.jpg


Two possibilities come to mind:
- One board, perhaps the CPU board from what you describe, has a fault 
increasing it's current draw.
 Without other boards plugged in on the same regulator, it's within the 
current capabilities of the regulator and 'appears' fine.
But with another board, the current draw is excessive for the regulator 
and current limiting kicks in.
Possible, but these 3 boards, controller for tape, disk pack, scanner 
(terminal), seem to be more greedy than the others (bad decoupling 
capacitors ?)

- How is the backplane for this machine organised: as a pure bus, or 
with dedicated slots for specific boards?

Dedicated slots for specific boards

Even if it is a bus structure, there might be requirements/limits on board 
combinations to distribute the load amongst the regulators.
Might the machine have been misconfigured by someone moving boards around, so 
that 2 heavy load boards end up on the same regulator and send it into current 
limiting?
Unlikely, the stickers on the chassis indicate the location of the 
boards, this seems to be like that since factory.

A minor comment regarding the components in the power supply: Q13 is a stage in 
the regulator drivers and as consequential as other components such as Q2.

Do you think that Q12 (linked to defective A1 / + 5v) could be the culprit?

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

2017-08-23 Thread Brent Hilpert via cctalk 
On 2017-Aug-23, at 6:17 AM, Dominique Carlier via cctalk wrote:
> Here is the situation.
> 
> The + 5V 12A that collapses comes out from pins 10-14 / 36-40, the other + 5V 
> 12A (pins 15-22 / 36-40) never goes down.
> 
> All that I surrounded in green on that image (1950×2361, zoomable) are the 
> components that I tested on the power supply G2, A3 motherboard, regulation 
> board and heatsink A1 + A2:
> http://www.zeltrax.com/classiccmp_forum/psu_g2_test/g2_tested_components.jpg
> 
> To eliminate some doubts and because I do not have some spare parts on hand, 
> I switched the modules A1 and A2, same result. Idem with the transistors 
> 2N2905, same result.
> The result is always the same : it's always the +5V on pins 10-14 / 36-40 
> that collapses, never the other output.
> 
> Some resistors are not yet tested is because these must be de-soldered for a 
> valid test, but the printed circuit is very fragile and many component have 
> legs bent into the weld.
> 
> Except for the not tested components (among others the LM376, the rectifier 
> diodes) At this stage I start again to suspect a little everything. The 
> famous large capacitors of the power supply (C1 to C4). But also a possible 
> problems on the boards of the computer itself.
> 
> As one of you mentioned, the hypothesis of shorted decoupling capacitors on 
> the boards could put the power supply in default.
> 
> Note that the machine runs normally with the CPU board, three core memory 
> boards (400w each) + two multiplexing boards for terminals + the printer 
> board.
> If I add only one of these remaining board:
> - Disk Pack Controller
> - 9-track tape Controller
> - "scanner" board (also for terminals)
> 
> -> Power Fail.
> 
> Note that : if I only connect the CPU and the disk pack controller card: 
> Power Fail too !!
> 
> What makes me doubtful about this scenario is that I can not imagine that 
> these three boards, each causing the Power Fail, could fail simultaneously. 
> Remember that the first time I powered up the beast (one big hour), the 
> machine was working with all the boards and Power Fail appeared at once.
> I have not retested since but also note that by adding an external power 
> supply just for the deficient + 5V , the machine has restarted and even 
> booted the operating system.
> 
> If you have another ideas? LM376?


Am I correct in inferring that this machine (the processor) has four +5V 
regulators?:  it appears there are 2 power supply chassis (rear photo), each 
with 2 regulators,
or are those 2 chassis not identical and there are only to two +5 regulators?

Either way, is it documented or has it been mapped out how the regulators are 
distributed to the bus/backplane slots?
If not, I would suggest doing so to start with, so you know what slots & boards 
each regulator is supplying power to.

Two possibilities come to mind:
- One board, perhaps the CPU board from what you describe, has a fault 
increasing it's current draw.
 Without other boards plugged in on the same regulator, it's within the 
current capabilities of the regulator and 'appears' fine.
But with another board, the current draw is excessive for the regulator 
and current limiting kicks in.

- How is the backplane for this machine organised: as a pure bus, or 
with dedicated slots for specific boards?
Even if it is a bus structure, there might be requirements/limits on 
board combinations to distribute the load amongst the regulators.
Might the machine have been misconfigured by someone moving boards 
around, so that 2 heavy load boards end up on the same
regulator and send it into current limiting?

A minor comment regarding the components in the power supply: Q13 is a stage in 
the regulator drivers and as consequential as other components such as Q2.

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

2017-08-23 Thread Dominique Carlier via cctalk 

Here is the situation.

The + 5V 12A that collapses comes out from pins 10-14 / 36-40, the other 
+ 5V 12A (pins 15-22 / 36-40) never goes down.


All that I surrounded in green on that image (1950×2361, zoomable) are 
the components that I tested on the power supply G2, A3 motherboard, 
regulation board and heatsink A1 + A2:

http://www.zeltrax.com/classiccmp_forum/psu_g2_test/g2_tested_components.jpg

To eliminate some doubts and because I do not have some spare parts on 
hand, I switched the modules A1 and A2, same result. Idem with the 
transistors 2N2905, same result.
The result is always the same : it's always the +5V on pins 10-14 / 
36-40 that collapses, never the other output.


Some resistors are not yet tested is because these must be de-soldered 
for a valid test, but the printed circuit is very fragile and many 
component have legs bent into the weld.


Except for the not tested components (among others the LM376, the 
rectifier diodes) At this stage I start again to suspect a little 
everything. The famous large capacitors of the power supply (C1 to C4). 
But also a possible problems on the boards of the computer itself.


As one of you mentioned, the hypothesis of shorted decoupling capacitors 
on the boards could put the power supply in default.


Note that the machine runs normally with the CPU board, three core 
memory boards (400w each) + two multiplexing boards for terminals + the 
printer board.

If I add only one of these remaining board:
- Disk Pack Controller
- 9-track tape Controller
- "scanner" board (also for terminals)

-> Power Fail.

Note that : if I only connect the CPU and the disk pack controller card: 
Power Fail too !!


What makes me doubtful about this scenario is that I can not imagine 
that these three boards, each causing the Power Fail, could fail 
simultaneously. Remember that the first time I powered up the beast (one 
big hour), the machine was working with all the boards and Power Fail 
appeared at once.
I have not retested since but also note that by adding an external power 
supply just for the deficient + 5V , the machine has restarted and even 
booted the operating system.


If you have another ideas? LM376?

Thanks

Dominique


On 20/08/2017 09:08, Brent Hilpert wrote:

On 2017-Aug-19, at 12:10 PM, Dominique Carlier via cctalk wrote:

Maybe it's better to give us all the useful information these power supplies, 
moreover it might be useful to other people with the same computer.

An overall bloc diagram of the D-116 power supply including G1 and G2.
http://www.zeltrax.com/classiccmp_forum/psu_overall_bloc_diagram.jpg

The complete schematics of the part of the power supply named G2.
http://www.zeltrax.com/classiccmp_forum/g2_schematics.jpg

A drawing of the regulation board of the power supply G2 with the physical 
locations of the components.
http://www.zeltrax.com/classiccmp_forum/g2_regulator_board.jpg

The schematics of this regulation board.
http://www.zeltrax.com/classiccmp_forum/g2_regulator_board_schematics.jpg

And a bit of literature concerning the principle of operation about the 
regulation with this PSU (you will understand better why I am a little bit lost 
;-) This principle of regulation with a panoply of verification and Protection 
systems everywhere is unusual for me)
http://www.zeltrax.com/classiccmp_forum/psu_regulation_principe.jpg

I have already tried without the CPU board: same symptoms. Next step, try to 
check the capacitors in operation.



Results of the observations:
- This is definitely the regulated +5V of the G2 power supply. More I add 
boards more the + 5v level goes down. +5v, +4.8v, +3.6v, +2.9v. It remains 
stable however with just the CPU and the three core memory boards, it becomes 
difficult for the power supply when I add boards in addition to these.
- This is definitely not a problem at the level of the Power Fail circuit.
- The big capacitors are not in fault (I rechecked twice).
- So this maybe a problem at the level of the regulation itself, the +5V 
balancing system ?

Question: a faulty voltage regulator can behave in this way? I always thought 
it worked or it did not work, but not between the two states depending on the 
charge.

(In answer to the question, yes, a faulty regulator can produce 'in-between' 
output voltage.)

As is typical for power supplies of this type and era, this power supply 
includes current limiting circuitry.

The current-limiting circuitry will throttle down the output voltage (not shut 
it off completely) as the output current draw goes above a design limit.
This would appear to fit the symptoms you describe.

The current-limiting circuitry works by placing a small-value resistor in the 
current path after the main regulator transistor(s) (aka pass transistors) but 
prior to the voltage-regulation sense point.
A transistor senses the voltage across this R.
As the output current increases, the voltage across the current-sense R 
increases, at some point the transistor starts to

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

2017-08-21 Thread Brent Hilpert via cctalk 

On 2017-Aug-21, at 8:46 AM, Dominique Carlier via cctalk wrote:

>> As is typical for power supplies of this type and era, this power supply 
>> includes current limiting circuitry.
>> 
>> The current-limiting circuitry will throttle down the output voltage (not 
>> shut it off completely) as the output current draw goes above a design limit.
>> This would appear to fit the symptoms you describe.
>> 
>> The current-limiting circuitry works by placing a small-value resistor in 
>> the current path after the main regulator transistor(s) (aka pass 
>> transistors) but prior to the voltage-regulation sense point.
>> A transistor senses the voltage across this R.
>> As the output current increases, the voltage across the current-sense R 
>> increases, at some point the transistor starts to turn on, and the 
>> transistor is connected in such a way that as it turns on it reduces the 
>> drive to the pass transistors, throttling down the output voltage.
>> 
>> Arbitrarily using the "A2" heatsink half of the two +5 supplies in this 
>> power supply for component references, the current-sense R is comprised of a 
>> series-parallel circuit formed by the BE junctions of the 2 pass transistors 
>> (A2.Q1, A2.Q2), the two 0.1ohm Rs on the emitters of the pass transistors 
>> (A3.R10,A3.R11), the 47ohm Rs between B of those transistors, A3.R23, 
>> A3A1A1.R8, 376.R9, along with additional influence by 376.R8 and A3A1A1.R10.
>> The current sense transistor is inside the LM376 (see internal schematic), 
>> 376.Q16 between pins 1 & 8, controlling the 1st-stage driver transistor 
>> 376.Q14.
>> 
>> There are various things that could go wrong on this circuitry.
>> Anything that upsets the current-sense resistance network to cause the net R 
>> to increase will lower the output current that can be drawn (that is, the 
>> current limiting circuitry will start kicking in too 'early').
>> 
>> A likely scenario is one of the pass transistors has failed open.
>> This would take out a parallel leg of the current-sense resistance.
>> All current would  be forced through the good pass transistor and it's 
>> emitter resistor, raising the current-sense voltage for a given output 
>> current.
>> The current-limiting circuitry would kick in at a lower current than the 
>> design intention.
>> This is beneficial inasmuch as it would work to save the good pass 
>> transistor.
>> 
>> The 0.1 ohm 9W emitter resistors are critical, although they're probably 
>> wirewound and fairly reliable unless quite overstressed.
>> One of these resistors being open would result in the same operation as an 
>> open pass transistor.
>> You'll have difficulty measuring them with accuracy but you could do some 
>> sanity checks for continuity around both the pass transistor circuit legs,
>> as well as checking the pass transistor BC/BE junctions.
>> 
>> (In principle, the 'proper' thing to do in this area is look at what the 
>> current-sense voltage is doing, but that requires knowing what the target V 
>> is. Could compare with the other half of the supply.)
>> 
>> None of this is to suggest this area is necessarily at fault, or rule out 
>> other areas of the supply.
>> 
>> Another possible fault that would fit the symptom (decreasing voltage as 
>> current draw increases, if that's what's going on) is inadequate (partially 
>> failed) drive to the pass transistors.
>> In short, anything reducing the power gain of the regulator error amplifier 
>> could produce this symptom.
>> 

> 
> Also following the suggestions of Curious Marc, I focus now on the comparison 
> between the two almost identical circuits that deliver the regulated + 5V on 
> G2.
> 
> Following your explanations, I started by checking the transistors and 
> resistors on the heatsinks A1 and A2, and also checking the resistors of 0.1 
> Ω (R10 to R13)
> 
> http://www.zeltrax.com/classiccmp_forum/psu_g2_test/cheked.jpg
> 
> But first I see on the schematic that these transistors are supposed to be 
> "2N6254", but I see on A1 and A2 that the 4 transistors are "7540" (full 
> name: POWER PHYSICS 001554 7540), I do not find The datasheet of this model.
> 
> http://www.zeltrax.com/classiccmp_forum/psu_g2_test/serie_pass_transistor.jpg
> 
> The results of the test on the pass transistors:
> By doing the various checks between B E C for NPN transistor, no problems. No 
> unwanted open or closed circuit at wrong place.
> However if I measure the value between B and E, on all the transistors I read 
> + - 0.510 except for one where it is + -0.440, it is Q2 on A1 which is 
> precisely the board that delivers the + 5V which collapse. Is this transistor 
> defective?
> 
> The small resistances which are between the bases and collectors of each 
> transistors all show + -50 Ω (they are supposed to be 47 Ω but I imagine it's 
> OK like that)
> But about R10, R11, R12 and R13, these resistors are supposed to be have a 
> value of 0.1 Ω , right?
> Because for these 4 resistors I read values

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

2017-08-21 Thread Dominique Carlier via cctalk 
Because I had removed every wires to test transistors on A1 and A2, and 
since I have to buy 4 new 0.1ohm resistors and an equivalent of 2N6254, 
in the meantime because they are identical I decided to interchange A1 
and A2, I was hoping note a +5V collapsed on the other output but no, it 
is always the same output which is in default, the one that is 
associated with A1. It is therefore possible that the problem is not at 
the level of these series pass transistors.


Maybe Q2 on the regulator board ?


On 20/08/2017 09:25, Brent Hilpert via cctalk wrote:

On 2017-Aug-20, at 12:08 AM, Brent Hilpert via cctalk wrote:

On 2017-Aug, at 12:10 PM, Dominique Carlier via cctalk wrote:

Question: a faulty voltage regulator can behave in this way? I always thought 
it worked or it did not work, but not between the two states depending on the 
charge.

(In answer to the question, yes, a faulty regulator can produce 'in-between' 
output voltage.)


Should modify that answer a little: a regulator like this can, not just if 
faulty, but also by design intention, produce an 'in-between' output voltage, 
as per the functioning of the current-limit circuitry.

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

2017-08-21 Thread Dominique Carlier via cctalk 

Hello,

Yes, it is a "Fluke 73" maybe not enough accurate for that kind of 
measurements ?



On 21/08/2017 18:53, Anders Nelson via cctalk wrote:

Hi Dominique,

Are you using a standard DMM to make your resistance measurements? If not,
you may have more consistent results by using a laboratory DMM that is
rated to measure milliohms.

On Mon, Aug 21, 2017 at 11:47 AM Dominique Carlier via cctalk <
cctalk@classiccmp.org> wrote:


Thank you very much for these valuable detailed information! :-)

Also following the suggestions of Curious Marc, I focus now on the
comparison between the two almost identical circuits that deliver the
regulated + 5V on G2.

Following your explanations, I started by checking the transistors and
resistors on the heatsinks A1 and A2, and also checking the resistors of
0.1 Ω (R10 to R13)

http://www.zeltrax.com/classiccmp_forum/psu_g2_test/cheked.jpg

But first I see on the schematic that these transistors are supposed to
be "2N6254", but I see on A1 and A2 that the 4 transistors are "7540"
(full name: POWER PHYSICS 001554 7540), I do not find The datasheet of
this model.


http://www.zeltrax.com/classiccmp_forum/psu_g2_test/serie_pass_transistor.jpg

The results of the test on the pass transistors:
By doing the various checks between B E C for NPN transistor, no
problems. No unwanted open or closed circuit at wrong place.
However if I measure the value between B and E, on all the transistors I
read + - 0.510 except for one where it is + -0.440, it is Q2 on A1 which
is precisely the board that delivers the + 5V which collapse. Is this
transistor defective?

The small resistances which are between the bases and collectors of each
transistors all show + -50 Ω (they are supposed to be 47 Ω but I imagine
it's OK like that)
But about R10, R11, R12 and R13, these resistors are supposed to be have
a value of 0.1 Ω , right?
Because for these 4 resistors I read values ​​ranging from 0.2 to 0.4 Ω!

http://www.zeltrax.com/classiccmp_forum/psu_g2_test/resistor_check.jpg

Strange thing, today I take the measurements again (with two different
multi-meters to be sure) and the values ​​today are different, located
between 0.8 and 1 Ω !! I do not understand this variation, I had
unwrapped only one leg, I removed both now, same type of result: 0.9 Ω !

Unfortunately because these 4 resistors are in the same state, these are
probably not the cause of the collapsed +5V only on the side of A1, What
is your opinion about that?
Anyway, I'm going to change those resistors for sure. I will also change
the transistor which only passes 0.44 instead of 0.52, I intend to put
an equivalent of 2N6254 hoping that the actual 7540 are also an
equivalent of the 2N6254 mentioned in the schematics.

Thanks a lot for your help !

Dominique

On 20/08/2017 09:08, Brent Hilpert wrote:

On 2017-Aug-19, at 12:10 PM, Dominique Carlier via cctalk wrote:

Maybe it's better to give us all the useful information these power

supplies, moreover it might be useful to other people with the same
computer.

An overall bloc diagram of the D-116 power supply including G1 and G2.
http://www.zeltrax.com/classiccmp_forum/psu_overall_bloc_diagram.jpg

The complete schematics of the part of the power supply named G2.
http://www.zeltrax.com/classiccmp_forum/g2_schematics.jpg

A drawing of the regulation board of the power supply G2 with the

physical locations of the components.

http://www.zeltrax.com/classiccmp_forum/g2_regulator_board.jpg

The schematics of this regulation board.


http://www.zeltrax.com/classiccmp_forum/g2_regulator_board_schematics.jpg

And a bit of literature concerning the principle of operation about the

regulation with this PSU (you will understand better why I am a little bit
lost ;-) This principle of regulation with a panoply of verification and
Protection systems everywhere is unusual for me)

http://www.zeltrax.com/classiccmp_forum/psu_regulation_principe.jpg

I have already tried without the CPU board: same symptoms. Next step,

try to check the capacitors in operation.

Results of the observations:
- This is definitely the regulated +5V of the G2 power supply. More I

add boards more the + 5v level goes down. +5v, +4.8v, +3.6v, +2.9v. It
remains stable however with just the CPU and the three core memory boards,
it becomes difficult for the power supply when I add boards in addition to
these.

- This is definitely not a problem at the level of the Power Fail

circuit.

- The big capacitors are not in fault (I rechecked twice).
- So this maybe a problem at the level of the regulation itself, the

+5V balancing system ?

Question: a faulty voltage regulator can behave in this way? I always

thought it worked or it did not work, but not between the two states
depending on the charge.

(In answer to the question, yes, a faulty regulator can produce

'in-between' output voltage.)

As is typical for power supplies of this type and era, this power supply

includes current limiting circuitry.

The current-limiting

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

2017-08-21 Thread Anders Nelson via cctalk 
Hi Dominique,

Are you using a standard DMM to make your resistance measurements? If not,
you may have more consistent results by using a laboratory DMM that is
rated to measure milliohms.

On Mon, Aug 21, 2017 at 11:47 AM Dominique Carlier via cctalk <
cctalk@classiccmp.org> wrote:

>
> Thank you very much for these valuable detailed information! :-)
>
> Also following the suggestions of Curious Marc, I focus now on the
> comparison between the two almost identical circuits that deliver the
> regulated + 5V on G2.
>
> Following your explanations, I started by checking the transistors and
> resistors on the heatsinks A1 and A2, and also checking the resistors of
> 0.1 Ω (R10 to R13)
>
> http://www.zeltrax.com/classiccmp_forum/psu_g2_test/cheked.jpg
>
> But first I see on the schematic that these transistors are supposed to
> be "2N6254", but I see on A1 and A2 that the 4 transistors are "7540"
> (full name: POWER PHYSICS 001554 7540), I do not find The datasheet of
> this model.
>
>
> http://www.zeltrax.com/classiccmp_forum/psu_g2_test/serie_pass_transistor.jpg
>
> The results of the test on the pass transistors:
> By doing the various checks between B E C for NPN transistor, no
> problems. No unwanted open or closed circuit at wrong place.
> However if I measure the value between B and E, on all the transistors I
> read + - 0.510 except for one where it is + -0.440, it is Q2 on A1 which
> is precisely the board that delivers the + 5V which collapse. Is this
> transistor defective?
>
> The small resistances which are between the bases and collectors of each
> transistors all show + -50 Ω (they are supposed to be 47 Ω but I imagine
> it's OK like that)
> But about R10, R11, R12 and R13, these resistors are supposed to be have
> a value of 0.1 Ω , right?
> Because for these 4 resistors I read values ​​ranging from 0.2 to 0.4 Ω!
>
> http://www.zeltrax.com/classiccmp_forum/psu_g2_test/resistor_check.jpg
>
> Strange thing, today I take the measurements again (with two different
> multi-meters to be sure) and the values ​​today are different, located
> between 0.8 and 1 Ω !! I do not understand this variation, I had
> unwrapped only one leg, I removed both now, same type of result: 0.9 Ω !
>
> Unfortunately because these 4 resistors are in the same state, these are
> probably not the cause of the collapsed +5V only on the side of A1, What
> is your opinion about that?
> Anyway, I'm going to change those resistors for sure. I will also change
> the transistor which only passes 0.44 instead of 0.52, I intend to put
> an equivalent of 2N6254 hoping that the actual 7540 are also an
> equivalent of the 2N6254 mentioned in the schematics.
>
> Thanks a lot for your help !
>
> Dominique
>
> On 20/08/2017 09:08, Brent Hilpert wrote:
> > On 2017-Aug-19, at 12:10 PM, Dominique Carlier via cctalk wrote:
> >> Maybe it's better to give us all the useful information these power
> supplies, moreover it might be useful to other people with the same
> computer.
> >>
> >> An overall bloc diagram of the D-116 power supply including G1 and G2.
> >> http://www.zeltrax.com/classiccmp_forum/psu_overall_bloc_diagram.jpg
> >>
> >> The complete schematics of the part of the power supply named G2.
> >> http://www.zeltrax.com/classiccmp_forum/g2_schematics.jpg
> >>
> >> A drawing of the regulation board of the power supply G2 with the
> physical locations of the components.
> >> http://www.zeltrax.com/classiccmp_forum/g2_regulator_board.jpg
> >>
> >> The schematics of this regulation board.
> >>
> http://www.zeltrax.com/classiccmp_forum/g2_regulator_board_schematics.jpg
> >>
> >> And a bit of literature concerning the principle of operation about the
> regulation with this PSU (you will understand better why I am a little bit
> lost ;-) This principle of regulation with a panoply of verification and
> Protection systems everywhere is unusual for me)
> >> http://www.zeltrax.com/classiccmp_forum/psu_regulation_principe.jpg
> >>
> >> I have already tried without the CPU board: same symptoms. Next step,
> try to check the capacitors in operation.
> >>> Results of the observations:
> >>> - This is definitely the regulated +5V of the G2 power supply. More I
> add boards more the + 5v level goes down. +5v, +4.8v, +3.6v, +2.9v. It
> remains stable however with just the CPU and the three core memory boards,
> it becomes difficult for the power supply when I add boards in addition to
> these.
> >>> - This is definitely not a problem at the level of the Power Fail
> circuit.
> >>> - The big capacitors are not in fault (I rechecked twice).
> >>> - So this maybe a problem at the level of the regulation itself, the
> +5V balancing system ?
> >>>
> >>> Question: a faulty voltage regulator can behave in this way? I always
> thought it worked or it did not work, but not between the two states
> depending on the charge.
> > (In answer to the question, yes, a faulty regulator can produce
> 'in-between' output voltage.)
> >
> > As is typical for power

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

2017-08-21 Thread Dominique Carlier via cctalk 


Thank you very much for these valuable detailed information! :-)

Also following the suggestions of Curious Marc, I focus now on the 
comparison between the two almost identical circuits that deliver the 
regulated + 5V on G2.


Following your explanations, I started by checking the transistors and 
resistors on the heatsinks A1 and A2, and also checking the resistors of 
0.1 Ω (R10 to R13)


http://www.zeltrax.com/classiccmp_forum/psu_g2_test/cheked.jpg

But first I see on the schematic that these transistors are supposed to 
be "2N6254", but I see on A1 and A2 that the 4 transistors are "7540" 
(full name: POWER PHYSICS 001554 7540), I do not find The datasheet of 
this model.


http://www.zeltrax.com/classiccmp_forum/psu_g2_test/serie_pass_transistor.jpg

The results of the test on the pass transistors:
By doing the various checks between B E C for NPN transistor, no 
problems. No unwanted open or closed circuit at wrong place.
However if I measure the value between B and E, on all the transistors I 
read + - 0.510 except for one where it is + -0.440, it is Q2 on A1 which 
is precisely the board that delivers the + 5V which collapse. Is this 
transistor defective?


The small resistances which are between the bases and collectors of each 
transistors all show + -50 Ω (they are supposed to be 47 Ω but I imagine 
it's OK like that)
But about R10, R11, R12 and R13, these resistors are supposed to be have 
a value of 0.1 Ω , right?

Because for these 4 resistors I read values ​​ranging from 0.2 to 0.4 Ω!

http://www.zeltrax.com/classiccmp_forum/psu_g2_test/resistor_check.jpg

Strange thing, today I take the measurements again (with two different 
multi-meters to be sure) and the values ​​today are different, located 
between 0.8 and 1 Ω !! I do not understand this variation, I had 
unwrapped only one leg, I removed both now, same type of result: 0.9 Ω !


Unfortunately because these 4 resistors are in the same state, these are 
probably not the cause of the collapsed +5V only on the side of A1, What 
is your opinion about that?
Anyway, I'm going to change those resistors for sure. I will also change 
the transistor which only passes 0.44 instead of 0.52, I intend to put 
an equivalent of 2N6254 hoping that the actual 7540 are also an 
equivalent of the 2N6254 mentioned in the schematics.


Thanks a lot for your help !

Dominique

On 20/08/2017 09:08, Brent Hilpert wrote:

On 2017-Aug-19, at 12:10 PM, Dominique Carlier via cctalk wrote:

Maybe it's better to give us all the useful information these power supplies, 
moreover it might be useful to other people with the same computer.

An overall bloc diagram of the D-116 power supply including G1 and G2.
http://www.zeltrax.com/classiccmp_forum/psu_overall_bloc_diagram.jpg

The complete schematics of the part of the power supply named G2.
http://www.zeltrax.com/classiccmp_forum/g2_schematics.jpg

A drawing of the regulation board of the power supply G2 with the physical 
locations of the components.
http://www.zeltrax.com/classiccmp_forum/g2_regulator_board.jpg

The schematics of this regulation board.
http://www.zeltrax.com/classiccmp_forum/g2_regulator_board_schematics.jpg

And a bit of literature concerning the principle of operation about the 
regulation with this PSU (you will understand better why I am a little bit lost 
;-) This principle of regulation with a panoply of verification and Protection 
systems everywhere is unusual for me)
http://www.zeltrax.com/classiccmp_forum/psu_regulation_principe.jpg

I have already tried without the CPU board: same symptoms. Next step, try to 
check the capacitors in operation.

Results of the observations:
- This is definitely the regulated +5V of the G2 power supply. More I add 
boards more the + 5v level goes down. +5v, +4.8v, +3.6v, +2.9v. It remains 
stable however with just the CPU and the three core memory boards, it becomes 
difficult for the power supply when I add boards in addition to these.
- This is definitely not a problem at the level of the Power Fail circuit.
- The big capacitors are not in fault (I rechecked twice).
- So this maybe a problem at the level of the regulation itself, the +5V 
balancing system ?

Question: a faulty voltage regulator can behave in this way? I always thought 
it worked or it did not work, but not between the two states depending on the 
charge.

(In answer to the question, yes, a faulty regulator can produce 'in-between' 
output voltage.)

As is typical for power supplies of this type and era, this power supply 
includes current limiting circuitry.

The current-limiting circuitry will throttle down the output voltage (not shut 
it off completely) as the output current draw goes above a design limit.
This would appear to fit the symptoms you describe.

The current-limiting circuitry works by placing a small-value resistor in the 
current path after the main regulator transistor(s) (aka pass transistors) but 
prior to the voltage-regulation sense point.
A transistor senses

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

2017-08-20 Thread Brent Hilpert via cctalk 
On 2017-Aug-20, at 12:08 AM, Brent Hilpert via cctalk wrote:
> On 2017-Aug, at 12:10 PM, Dominique Carlier via cctalk wrote:
>>> 
>>> Question: a faulty voltage regulator can behave in this way? I always 
>>> thought it worked or it did not work, but not between the two states 
>>> depending on the charge.
> 
> (In answer to the question, yes, a faulty regulator can produce 'in-between' 
> output voltage.)


Should modify that answer a little: a regulator like this can, not just if 
faulty, but also by design intention, produce an 'in-between' output voltage, 
as per the functioning of the current-limit circuitry.

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

2017-08-20 Thread Brent Hilpert via cctalk 
On 2017-Aug-19, at 12:10 PM, Dominique Carlier via cctalk wrote:
> Maybe it's better to give us all the useful information these power supplies, 
> moreover it might be useful to other people with the same computer.
> 
> An overall bloc diagram of the D-116 power supply including G1 and G2.
> http://www.zeltrax.com/classiccmp_forum/psu_overall_bloc_diagram.jpg
> 
> The complete schematics of the part of the power supply named G2.
> http://www.zeltrax.com/classiccmp_forum/g2_schematics.jpg
> 
> A drawing of the regulation board of the power supply G2 with the physical 
> locations of the components.
> http://www.zeltrax.com/classiccmp_forum/g2_regulator_board.jpg
> 
> The schematics of this regulation board.
> http://www.zeltrax.com/classiccmp_forum/g2_regulator_board_schematics.jpg
> 
> And a bit of literature concerning the principle of operation about the 
> regulation with this PSU (you will understand better why I am a little bit 
> lost ;-) This principle of regulation with a panoply of verification and 
> Protection systems everywhere is unusual for me)
> http://www.zeltrax.com/classiccmp_forum/psu_regulation_principe.jpg
> 
> I have already tried without the CPU board: same symptoms. Next step, try to 
> check the capacitors in operation.


>> Results of the observations:
>> - This is definitely the regulated +5V of the G2 power supply. More I add 
>> boards more the + 5v level goes down. +5v, +4.8v, +3.6v, +2.9v. It remains 
>> stable however with just the CPU and the three core memory boards, it 
>> becomes difficult for the power supply when I add boards in addition to 
>> these.
>> - This is definitely not a problem at the level of the Power Fail circuit.
>> - The big capacitors are not in fault (I rechecked twice).
>> - So this maybe a problem at the level of the regulation itself, the +5V 
>> balancing system ?
>> 
>> Question: a faulty voltage regulator can behave in this way? I always 
>> thought it worked or it did not work, but not between the two states 
>> depending on the charge.

(In answer to the question, yes, a faulty regulator can produce 'in-between' 
output voltage.)

As is typical for power supplies of this type and era, this power supply 
includes current limiting circuitry.

The current-limiting circuitry will throttle down the output voltage (not shut 
it off completely) as the output current draw goes above a design limit.
This would appear to fit the symptoms you describe.

The current-limiting circuitry works by placing a small-value resistor in the 
current path after the main regulator transistor(s) (aka pass transistors) but 
prior to the voltage-regulation sense point.
A transistor senses the voltage across this R.
As the output current increases, the voltage across the current-sense R 
increases, at some point the transistor starts to turn on, and the transistor 
is connected in such a way that as it turns on it reduces the drive to the pass 
transistors, throttling down the output voltage.

Arbitrarily using the "A2" heatsink half of the two +5 supplies in this power 
supply for component references, the current-sense R is comprised of a 
series-parallel circuit formed by the BE junctions of the 2 pass transistors 
(A2.Q1, A2.Q2), the two 0.1ohm Rs on the emitters of the pass transistors 
(A3.R10,A3.R11), the 47ohm Rs between B of those transistors, A3.R23, 
A3A1A1.R8, 376.R9, along with additional influence by 376.R8 and A3A1A1.R10.
The current sense transistor is inside the LM376 (see internal schematic), 
376.Q16 between pins 1 & 8, controlling the 1st-stage driver transistor 376.Q14.

There are various things that could go wrong on this circuitry.
Anything that upsets the current-sense resistance network to cause the net R to 
increase will lower the output current that can be drawn (that is, the current 
limiting circuitry will start kicking in too 'early').

A likely scenario is one of the pass transistors has failed open.
This would take out a parallel leg of the current-sense resistance.
All current would  be forced through the good pass transistor and it's emitter 
resistor, raising the current-sense voltage for a given output current.
The current-limiting circuitry would kick in at a lower current than the design 
intention.
This is beneficial inasmuch as it would work to save the good pass transistor.

The 0.1 ohm 9W emitter resistors are critical, although they're probably 
wirewound and fairly reliable unless quite overstressed.
One of these resistors being open would result in the same operation as an open 
pass transistor.
You'll have difficulty measuring them with accuracy but you could do some 
sanity checks for continuity around both the pass transistor circuit legs,
as well as checking the pass transistor BC/BE junctions.

(In principle, the 'proper' thing to do in this area is look at what the 
current-sense voltage is doing, but that requires knowing what the target V is. 
Could compare with the other half of the supply.)

None of this is to

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

2017-08-19 Thread Jon Elson via cctalk 
On 08/19/2017 11:29 AM, Rod Smallwood via cctalk wrote:
> Leaky Crowbar SCR?
>
Never heard of such a thing. SCRs are usually all the way
on, or all the way off. Why would it be sensitive to load on
the power supply?

Jon

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

2017-08-19 Thread Curious Marc via cctalk 
A straightforward linear supply. We should be able to get that puppy working. 
Looks like you have two of the same thing on G2, two +5V supplies. You could 
take advantage of that and compare voltages of one against the other at several 
points. You coukd also monitor the voltage on the non regulated side of the 
power transistors, if that crashes too, it's more likely it's a problem in the 
caps or the rectifier diodes. If it crashes after, transistors or regulation 
circuit could be suspect. Maybe we can do a Skype "en Francais"  and debug it 
together.
Marc


On Aug 19, 2017, at 12:10 PM, Dominique Carlier via cctalk 
 wrote:

Maybe it's better to give us all the useful information these power supplies, 
moreover it might be useful to other people with the same computer.

An overall bloc diagram of the D-116 power supply including G1 and G2.
http://www.zeltrax.com/classiccmp_forum/psu_overall_bloc_diagram.jpg

The complete schematics of the part of the power supply named G2.
http://www.zeltrax.com/classiccmp_forum/g2_schematics.jpg

A drawing of the regulation board of the power supply G2 with the physical 
locations of the components.
http://www.zeltrax.com/classiccmp_forum/g2_regulator_board.jpg

The schematics of this regulation board.
http://www.zeltrax.com/classiccmp_forum/g2_regulator_board_schematics.jpg

And a bit of literature concerning the principle of operation about the 
regulation with this PSU (you will understand better why I am a little bit lost 
;-) This principle of regulation with a panoply of verification and Protection 
systems everywhere is unusual for me)
http://www.zeltrax.com/classiccmp_forum/psu_regulation_principe.jpg

I have already tried without the CPU board: same symptoms. Next step, try to 
check the capacitors in operation.

And because all this is a little bit boring, here is, as a small gift, a photo 
gallery of the machine under different angles ;-)

Ensemble

http://www.zeltrax.com/classiccmp_forum/serie01/ensemble_01.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/ensemble_02.jpg 


D-116 Front panel

http://www.zeltrax.com/classiccmp_forum/serie01/d116_front_panel_01.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/d116_front_panel_02.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/d116_front_panel_03.jpg

D-116 open rack

http://www.zeltrax.com/classiccmp_forum/serie01/d116_open_01.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/d116_open_02.jpg

G2 regulator board

http://www.zeltrax.com/classiccmp_forum/serie01/g2_regulator_board.jpg

Disk Pack drive Diablo Model 40

http://www.zeltrax.com/classiccmp_forum/serie01/diskpack_drive_01.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/diskpack_drive_02.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/diskpack_drive_03.jpg

Mag-tape Pertec 8840A

http://www.zeltrax.com/classiccmp_forum/serie01/pertec_close.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/pertec_open_01.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/pertec_open_02.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/pertec_open_03.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/pertec_open_04.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/pertec_open_05.jpg

Drum printer Data Products model 2230

http://www.zeltrax.com/classiccmp_forum/serie01/printer_01.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/printer_02.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/printer_03.jpg

Terminal Entrex

http://www.zeltrax.com/classiccmp_forum/serie01/terminal.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/terminal_nacked.jpg

Rear panel / connectors

http://www.zeltrax.com/classiccmp_forum/serie01/rear_panel.jpg

From inside

http://www.zeltrax.com/classiccmp_forum/serie01/flat_cables.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/from_inside.jpg 


Haa I can't wait to operate this heavy machine! ;-)

Dominique

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

2017-08-19 Thread Dominique Carlier via cctalk 
Maybe it's better to give us all the useful information these power 
supplies, moreover it might be useful to other people with the same 
computer.


An overall bloc diagram of the D-116 power supply including G1 and G2.
http://www.zeltrax.com/classiccmp_forum/psu_overall_bloc_diagram.jpg

The complete schematics of the part of the power supply named G2.
http://www.zeltrax.com/classiccmp_forum/g2_schematics.jpg

A drawing of the regulation board of the power supply G2 with the 
physical locations of the components.

http://www.zeltrax.com/classiccmp_forum/g2_regulator_board.jpg

The schematics of this regulation board.
http://www.zeltrax.com/classiccmp_forum/g2_regulator_board_schematics.jpg

And a bit of literature concerning the principle of operation about the 
regulation with this PSU (you will understand better why I am a little 
bit lost ;-) This principle of regulation with a panoply of verification 
and Protection systems everywhere is unusual for me)

http://www.zeltrax.com/classiccmp_forum/psu_regulation_principe.jpg

I have already tried without the CPU board: same symptoms. Next step, 
try to check the capacitors in operation.


And because all this is a little bit boring, here is, as a small gift, a 
photo gallery of the machine under different angles ;-)


Ensemble

http://www.zeltrax.com/classiccmp_forum/serie01/ensemble_01.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/ensemble_02.jpg 



D-116 Front panel

http://www.zeltrax.com/classiccmp_forum/serie01/d116_front_panel_01.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/d116_front_panel_02.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/d116_front_panel_03.jpg

D-116 open rack

http://www.zeltrax.com/classiccmp_forum/serie01/d116_open_01.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/d116_open_02.jpg

G2 regulator board

http://www.zeltrax.com/classiccmp_forum/serie01/g2_regulator_board.jpg

Disk Pack drive Diablo Model 40

http://www.zeltrax.com/classiccmp_forum/serie01/diskpack_drive_01.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/diskpack_drive_02.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/diskpack_drive_03.jpg

Mag-tape Pertec 8840A

http://www.zeltrax.com/classiccmp_forum/serie01/pertec_close.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/pertec_open_01.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/pertec_open_02.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/pertec_open_03.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/pertec_open_04.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/pertec_open_05.jpg

Drum printer Data Products model 2230

http://www.zeltrax.com/classiccmp_forum/serie01/printer_01.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/printer_02.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/printer_03.jpg

Terminal Entrex

http://www.zeltrax.com/classiccmp_forum/serie01/terminal.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/terminal_nacked.jpg

Rear panel / connectors

http://www.zeltrax.com/classiccmp_forum/serie01/rear_panel.jpg

From inside

http://www.zeltrax.com/classiccmp_forum/serie01/flat_cables.jpg
http://www.zeltrax.com/classiccmp_forum/serie01/from_inside.jpg 



Haa I can't wait to operate this heavy machine! ;-)

Dominique

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

2017-08-19 Thread Rod Smallwood via cctalk 

Leaky Crowbar SCR?



On 19/08/2017 17:06, Jon Elson via cctalk wrote:

On 08/19/2017 03:17 AM, Dominique Carlier via cctalk wrote:

Hello Marc,

In fact no, i am not really sure, I checked twice all the
big filtering caps but as you with a low voltage tester.
These caps comes apparently from a new old stock and some
doubts persists now.
I admit, I don't know how to test these caps at rated
voltage with my tools or in situ with the caps inside the
working (and thus closed/packed/connected) PSUs


It could also be an open rectifier diode. The caps might
store enough charge to keep the regulator from dropping out
at light load, but the DC input sags under more load. You
could check for AC on the DC output when it starts to fail.
It could also be a fuse socket that has developed some
resistance, although when that gets bad, the heat causes the
fuse to fail. We had a Versatec printer that this would
happen to every 5 years or so. The fix was to clean the fuse
clip with the finest sandpaper available and put in a new
fuse (even if you caught it before the fuse blew.)

Jon


--
Wanted one pdp-8/i rocker switch leaver to copy.

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

2017-08-19 Thread Jon Elson via cctalk 
On 08/19/2017 03:17 AM, Dominique Carlier via cctalk wrote:
> Hello Marc,
>
> In fact no, i am not really sure, I checked twice all the
> big filtering caps but as you with a low voltage tester.
> These caps comes apparently from a new old stock and some
> doubts persists now.
> I admit, I don't know how to test these caps at rated
> voltage with my tools or in situ with the caps inside the
> working (and thus closed/packed/connected) PSUs
>
It could also be an open rectifier diode. The caps might
store enough charge to keep the regulator from dropping out
at light load, but the DC input sags under more load. You
could check for AC on the DC output when it starts to fail.
It could also be a fuse socket that has developed some
resistance, although when that gets bad, the heat causes the
fuse to fail. We had a Versatec printer that this would
happen to every 5 years or so. The fix was to clean the fuse
clip with the finest sandpaper available and put in a new
fuse (even if you caught it before the fuse blew.)

Jon

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

2017-08-19 Thread David Collins via cctalk 
An easy way to check the caps is to see what the voltage across them is like
when you put the system under load and the 'regulated' voltage drops.  If
the cap voltage drops substantially, or if you get a high ripple under load,
that's a good sign the caps are bad.

You mention that the +5V holds up with just the CPU and 3 memory boards and
then drops as you add more.  The CPU and memory boards should pull a fair
amount of power on their own so it seems strange the 5V isn't off to some
degree with just those boards.  Have you tried just those additional boards
without the CPU and memory boards to see if they may have bad components on
them that are loading the 5V rail?  Bad decoupling capacitors on boards can
short out/load up the supply rails and cause the problem you are seeing.  

David Collins

-Original Message-
From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Dominique
Carlier via cctalk
Sent: Saturday, 19 August 2017 6:17 PM
To: Curious Marc <curiousma...@gmail.com>; General Discussion: On-Topic and
Off-Topic Posts <cctalk@classiccmp.org>
Subject: Re: DCC-116 E / DATA GENERAL NOVA 2/10 / Nixdorf 620 - Restoring
and restarting

Hello Marc,

In fact no, i am not really sure, I checked twice all the big filtering caps
but as you with a low voltage tester. These caps comes apparently from a new
old stock and some doubts persists now.
I admit, I don't know how to test these caps at rated voltage with my tools
or in situ with the caps inside the working (and thus
closed/packed/connected) PSUs

Dominique

On 19/08/2017 07:11, Curious Marc wrote:
> Great work, you have isolated the supply fault. Looks like it's not
regulating, but the fact that it starts at 5V tells me it actually is, at
low current drain. Are you *really really* sure the filtering caps are good
*at rated voltage* (we had a recent case of caps that tested perfect with my
low voltage tester but were duds at their rated voltage)? Bad caps would
cause something like this. If not I'd usually start to check the regulating
power transistors. Could be anything else of course, having the schematics
would allow for a much more intelligent conversation instead of blind
speculation.
> Marc
>
> On Aug 18, 2017, at 10:25 AM, Dominique Carlier via cctalk
<cctalk@classiccmp.org> wrote:
>
> Some news !
>
> Following a risky way (but I did not see how to do otherwise), I
deactivated the Power Fail by hiding the contact number 23 of the two power
supplies.
> The idea was to avoid automatic protection by lowering the regulated
voltages (+5V and 15V) and see first which unit was involved (G1 or G2), and
also which voltages became weak, at what level it is lowered, and according
to which board (model or number of connected boards).
>
> Results of the observations:
> - This is definitely the regulated +5V of the G2 power supply. More I add
boards more the + 5v level goes down. +5v, +4.8v, +3.6v, +2.9v. It remains
stable however with just the CPU and the three core memory boards, it
becomes difficult for the power supply when I add boards in addition to
these.
> - This is definitely not a problem at the level of the Power Fail circuit.
> - The big capacitors are not in fault (I rechecked twice).
> - So this maybe a problem at the level of the regulation itself, the +5V
balancing system ?
>
> Question: a faulty voltage regulator can behave in this way? I always
thought it worked or it did not work, but not between the two states
depending on the charge.
>
> Anyway, suggestions are always welcome ;-)
>
> PS : I'm starting to want to put another power supply for that regulated
+5V, and bypass the +5V regulated of G2, but it would be a shame and not in
the spirit of a restoration in my opinion.
>
>
>
>
> -------- Forwarded Message ----
> Subject:Re: DCC-116 E / DATA GENERAL NOVA 2/10 / Nixdorf 620 -
Restoring and restarting
> Date:Wed, 16 Aug 2017 23:33:31 +0200
> From:Dominique Carlier <d...@skynet.be>
> To:Christian Kennedy via cctalk <cctalk@classiccmp.org>
>
>
>
> Hi !
>
> I finally find some time to work again on my D-116, try to find the 
> problem(s), thus principally at the level of PSUs.
> As you suggested, I inspected particularly the large capacitors of 
> both power supplies. I replaced those that appeared suspicious 
> according to the results via my ESR meter, but note that this one is 
> not supposed to be able to verify the capacitors of more than 22000μF. 
> I have also some doubt about the results (capacitor working with a real
charge or not).
>
> Anyway, unfortunately the problem is still there. I don't know where 
> to search now. If I understand well, the two power supplies can cause 
> a Power Fail if one of the regulated voltages were out of range. At 
> this point I do not know which of the two is in fault, because when 
> the

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

2017-08-19 Thread Dominique Carlier via cctalk 

Hello Marc,

In fact no, i am not really sure, I checked twice all the big filtering  
caps but as you with a low voltage tester. These caps comes apparently  
from a new old stock and some doubts persists now.
I admit, I don't know how to test these caps at rated voltage with my  
tools or in situ with the caps inside the working (and thus  
closed/packed/connected) PSUs


Dominique

On 19/08/2017 07:11, Curious Marc wrote:

Great work, you have isolated the supply fault. Looks like it's not regulating, 
but the fact that it starts at 5V tells me it actually is, at low current 
drain. Are you *really really* sure the filtering caps are good *at rated 
voltage* (we had a recent case of caps that tested perfect with my low voltage 
tester but were duds at their rated voltage)? Bad caps would cause something 
like this. If not I'd usually start to check the regulating power transistors. 
Could be anything else of course, having the schematics would allow for a much 
more intelligent conversation instead of blind speculation.
Marc

On Aug 18, 2017, at 10:25 AM, Dominique Carlier via cctalk 
<cctalk@classiccmp.org> wrote:

Some news !

Following a risky way (but I did not see how to do otherwise), I deactivated 
the Power Fail by hiding the contact number 23 of the two power supplies.
The idea was to avoid automatic protection by lowering the regulated voltages 
(+5V and 15V) and see first which unit was involved (G1 or G2), and also which 
voltages became weak, at what level it is lowered, and according to which board 
(model or number of connected boards).

Results of the observations:
- This is definitely the regulated +5V of the G2 power supply. More I add 
boards more the + 5v level goes down. +5v, +4.8v, +3.6v, +2.9v. It remains 
stable however with just the CPU and the three core memory boards, it becomes 
difficult for the power supply when I add boards in addition to these.
- This is definitely not a problem at the level of the Power Fail circuit.
- The big capacitors are not in fault (I rechecked twice).
- So this maybe a problem at the level of the regulation itself, the +5V 
balancing system ?

Question: a faulty voltage regulator can behave in this way? I always thought 
it worked or it did not work, but not between the two states depending on the 
charge.

Anyway, suggestions are always welcome ;-)

PS : I'm starting to want to put another power supply for that regulated +5V, 
and bypass the +5V regulated of G2, but it would be a shame and not in the 
spirit of a restoration in my opinion.




 Forwarded Message 
Subject:    Re: DCC-116 E / DATA GENERAL NOVA 2/10 / Nixdorf 620 - Restoring 
and restarting
Date:Wed, 16 Aug 2017 23:33:31 +0200
From:Dominique Carlier <d...@skynet.be>
To:Christian Kennedy via cctalk <cctalk@classiccmp.org>



Hi !

I finally find some time to work again on my D-116, try to find the
problem(s), thus principally at the level of PSUs.
As you suggested, I inspected particularly the large capacitors of both
power supplies. I replaced those that appeared suspicious according to
the results via my ESR meter, but note that this one is not supposed to
be able to verify the capacitors of more than 22000μF. I have also some
doubt about the results (capacitor working with a real charge or not).

Anyway, unfortunately the problem is still there. I don't know where to
search now. If I understand well, the two power supplies can cause a
Power Fail if one of the regulated voltages were out of range. At this
point I do not know which of the two is in fault, because when the Power
Fail is active the + 5V is automatically dropped around 1.5V.
Following the schematics I have focused my attention on the value of
some resistors with an important role in triggering this state (eg R18).
I found nothing abnormal, I checked all the capacitors, a large package
of resistances.

At this point what I know is that I can simultaneously connect the CPU
board and the three core memory boards without problem. If I add the
controller board for the removable hard disk drive or for the tape ->
Power Fail.
Interesting thing: if I connect only the CPU board and the disk
controller: Power Fail too. Maybe the PSU in default is the one that
supply the + 5V for the boards in the upper part of the rack? (slot 1
for the CPU, solt 4, 5 and 7 for the mem, slot 10 and 12 for tape and hdd)

I can provide pictures, schematics, ...

Regardless of this failure, I try to find information about what I could
install as an operating system on that big beast. If you have too any
ideas about that?

I would like to be able to do simple tasks such as managing files
(copying files from disk to tape and vice versa), being able to create
directories and sub directories, writing text, print on my drum printer,
programming in a simple language such as BASIC, and also, if I find a
communication board (on the CPU-board I don't found any trace of
components that evoke me an RS-232 in

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

2017-08-18 Thread Curious Marc via cctalk 
Great work, you have isolated the supply fault. Looks like it's not regulating, 
but the fact that it starts at 5V tells me it actually is, at low current 
drain. Are you *really really* sure the filtering caps are good *at rated 
voltage* (we had a recent case of caps that tested perfect with my low voltage 
tester but were duds at their rated voltage)? Bad caps would cause something 
like this. If not I'd usually start to check the regulating power transistors. 
Could be anything else of course, having the schematics would allow for a much 
more intelligent conversation instead of blind speculation.
Marc

On Aug 18, 2017, at 10:25 AM, Dominique Carlier via cctalk 
<cctalk@classiccmp.org> wrote:

Some news !

Following a risky way (but I did not see how to do otherwise), I deactivated 
the Power Fail by hiding the contact number 23 of the two power supplies.
The idea was to avoid automatic protection by lowering the regulated voltages 
(+5V and 15V) and see first which unit was involved (G1 or G2), and also which 
voltages became weak, at what level it is lowered, and according to which board 
(model or number of connected boards).

Results of the observations:
- This is definitely the regulated +5V of the G2 power supply. More I add 
boards more the + 5v level goes down. +5v, +4.8v, +3.6v, +2.9v. It remains 
stable however with just the CPU and the three core memory boards, it becomes 
difficult for the power supply when I add boards in addition to these.
- This is definitely not a problem at the level of the Power Fail circuit.
- The big capacitors are not in fault (I rechecked twice).
- So this maybe a problem at the level of the regulation itself, the +5V 
balancing system ?

Question: a faulty voltage regulator can behave in this way? I always thought 
it worked or it did not work, but not between the two states depending on the 
charge.

Anyway, suggestions are always welcome ;-)

PS : I'm starting to want to put another power supply for that regulated +5V, 
and bypass the +5V regulated of G2, but it would be a shame and not in the 
spirit of a restoration in my opinion.




 Forwarded Message 
Subject:    Re: DCC-116 E / DATA GENERAL NOVA 2/10 / Nixdorf 620 - Restoring 
and restarting
Date:Wed, 16 Aug 2017 23:33:31 +0200
From:Dominique Carlier <d...@skynet.be>
To:Christian Kennedy via cctalk <cctalk@classiccmp.org>



Hi !

I finally find some time to work again on my D-116, try to find the
problem(s), thus principally at the level of PSUs.
As you suggested, I inspected particularly the large capacitors of both
power supplies. I replaced those that appeared suspicious according to
the results via my ESR meter, but note that this one is not supposed to
be able to verify the capacitors of more than 22000μF. I have also some
doubt about the results (capacitor working with a real charge or not).

Anyway, unfortunately the problem is still there. I don't know where to
search now. If I understand well, the two power supplies can cause a
Power Fail if one of the regulated voltages were out of range. At this
point I do not know which of the two is in fault, because when the Power
Fail is active the + 5V is automatically dropped around 1.5V.
Following the schematics I have focused my attention on the value of
some resistors with an important role in triggering this state (eg R18).
I found nothing abnormal, I checked all the capacitors, a large package
of resistances.

At this point what I know is that I can simultaneously connect the CPU
board and the three core memory boards without problem. If I add the
controller board for the removable hard disk drive or for the tape ->
Power Fail.
Interesting thing: if I connect only the CPU board and the disk
controller: Power Fail too. Maybe the PSU in default is the one that
supply the + 5V for the boards in the upper part of the rack? (slot 1
for the CPU, solt 4, 5 and 7 for the mem, slot 10 and 12 for tape and hdd)

I can provide pictures, schematics, ...

Regardless of this failure, I try to find information about what I could
install as an operating system on that big beast. If you have too any
ideas about that?

I would like to be able to do simple tasks such as managing files
(copying files from disk to tape and vice versa), being able to create
directories and sub directories, writing text, print on my drum printer,
programming in a simple language such as BASIC, and also, if I find a
communication board (on the CPU-board I don't found any trace of
components that evoke me an RS-232 interface), communicate with another
machine, print on a teletype ... Does this seem possible for you with
this type of machine? If yes, with which OS?

I took tons of pictures of the machine from all angles, I will post them
soon ;-)

Dominique

> 
>> 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, s

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

2017-08-18 Thread Tapley, Mark via cctalk 
Dominique, 
I agree with Rod’s suggestion to check the current, but one other 
possibility is to check for small resistances, maybe considerably less than 1 
Ohm, somewhere between the 5V regulation and the delivery of 5V to the logic 
boards. If a connector  has corroded or a solder joint has developed a crack, 
there could be such a resistance. Then the regulator would actually be 
controlling the output to 5V but the logic boards would only be getting 4V, 3V, 
 etc. off of the bus. The difference would scale with the number of boards in 
the way you describe. 
Hope this helps, apologies if you have already looked at this.
- Mark
210-522-6025 office 
210-379-4635cell



On Aug 18, 2017, at 12:25 PM, Dominique Carlier via cctalk 
 wrote:

> Some news !
> 
> Following a risky way (but I did not see how to do otherwise), I deactivated 
> the Power Fail by hiding the contact number 23 of the two power supplies.
> The idea was to avoid automatic protection by lowering the regulated voltages 
> (+5V and 15V) and see first which unit was involved (G1 or G2), and also 
> which voltages became weak, at what level it is lowered, and according to 
> which board (model or number of connected boards).
> 
> Results of the observations:
> - This is definitely the regulated +5V of the G2 power supply. More I add 
> boards more the + 5v level goes down. +5v, +4.8v, +3.6v, +2.9v. It remains 
> stable however with just the CPU and the three core memory boards, it becomes 
> difficult for the power supply when I add boards in addition to these.
> - This is definitely not a problem at the level of the Power Fail circuit.
> - The big capacitors are not in fault (I rechecked twice).
> - So this maybe a problem at the level of the regulation itself, the +5V 
> balancing system ?
> 
> Question: a faulty voltage regulator can behave in this way? I always thought 
> it worked or it did not work, but not between the two states depending on the 
> charge.
> 
> Anyway, suggestions are always welcome ;-)
> 
> PS : I'm starting to want to put another power supply for that regulated +5V, 
> and bypass the +5V regulated of G2, but it would be a shame and not in the 
> spirit of a restoration in my opinion.

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

2017-08-18 Thread Rod Smallwood via cctalk 

Check the current



On 18/08/2017 18:25, Dominique Carlier via cctalk wrote:

Some news !

Following a risky way (but I did not see how to do otherwise), I 
deactivated the Power Fail by hiding the contact number 23 of the two 
power supplies.
The idea was to avoid automatic protection by lowering the regulated 
voltages (+5V and 15V) and see first which unit was involved (G1 or 
G2), and also which voltages became weak, at what level it is lowered, 
and according to which board (model or number of connected boards).


Results of the observations:
- This is definitely the regulated +5V of the G2 power supply. More I 
add boards more the + 5v level goes down. +5v, +4.8v, +3.6v, +2.9v. It 
remains stable however with just the CPU and the three core memory 
boards, it becomes difficult for the power supply when I add boards in 
addition to these.
- This is definitely not a problem at the level of the Power Fail 
circuit.

- The big capacitors are not in fault (I rechecked twice).
- So this maybe a problem at the level of the regulation itself, the 
+5V balancing system ?


Question: a faulty voltage regulator can behave in this way? I always 
thought it worked or it did not work, but not between the two states 
depending on the charge.


Anyway, suggestions are always welcome ;-)

PS : I'm starting to want to put another power supply for that 
regulated +5V, and bypass the +5V regulated of G2, but it would be a 
shame and not in the spirit of a restoration in my opinion.





 Forwarded Message 
Subject: Re: DCC-116 E / DATA GENERAL NOVA 2/10 / Nixdorf 620 - 
Restoring and restarting

Date: Wed, 16 Aug 2017 23:33:31 +0200
From: Dominique Carlier <d...@skynet.be>
To: Christian Kennedy via cctalk <cctalk@classiccmp.org>



Hi !

I finally find some time to work again on my D-116, try to find the
problem(s), thus principally at the level of PSUs.
As you suggested, I inspected particularly the large capacitors of both
power supplies. I replaced those that appeared suspicious according to
the results via my ESR meter, but note that this one is not supposed to
be able to verify the capacitors of more than 22000μF. I have also some
doubt about the results (capacitor working with a real charge or not).

Anyway, unfortunately the problem is still there. I don't know where to
search now. If I understand well, the two power supplies can cause a
Power Fail if one of the regulated voltages were out of range. At this
point I do not know which of the two is in fault, because when the Power
Fail is active the + 5V is automatically dropped around 1.5V.
Following the schematics I have focused my attention on the value of
some resistors with an important role in triggering this state (eg R18).
I found nothing abnormal, I checked all the capacitors, a large package
of resistances.

At this point what I know is that I can simultaneously connect the CPU
board and the three core memory boards without problem. If I add the
controller board for the removable hard disk drive or for the tape ->
Power Fail.
Interesting thing: if I connect only the CPU board and the disk
controller: Power Fail too. Maybe the PSU in default is the one that
supply the + 5V for the boards in the upper part of the rack? (slot 1
for the CPU, solt 4, 5 and 7 for the mem, slot 10 and 12 for tape and 
hdd)


I can provide pictures, schematics, ...

Regardless of this failure, I try to find information about what I could
install as an operating system on that big beast. If you have too any
ideas about that?

I would like to be able to do simple tasks such as managing files
(copying files from disk to tape and vice versa), being able to create
directories and sub directories, writing text, print on my drum printer,
programming in a simple language such as BASIC, and also, if I find a
communication board (on the CPU-board I don't found any trace of
components that evoke me an RS-232 interface), communicate with another
machine, print on a teletype ... Does this seem possible for you with
this type of machine? If yes, with which OS?

I took tons of pictures of the machine from all angles, I will post them
soon ;-)

Dominique




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.

It's a switcher; look at the caps in the LC filter (downstream of the
series pass transistor) that, together with the inductor, form the
energy storage mechanism of the power supply; check the source supply as
well.  The fact that it eventually comes back suggests that the
reference, comparator and pass device are probably functioning.




--
Wanted one pdp-8/i rocker switch leaver to copy.

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

2017-08-18 Thread Dominique Carlier via cctalk 

Some news !

Following a risky way (but I did not see how to do otherwise), I 
deactivated the Power Fail by hiding the contact number 23 of the two 
power supplies.
The idea was to avoid automatic protection by lowering the regulated 
voltages (+5V and 15V) and see first which unit was involved (G1 or G2), 
and also which voltages became weak, at what level it is lowered, and 
according to which board (model or number of connected boards).


Results of the observations:
- This is definitely the regulated +5V of the G2 power supply. More I 
add boards more the + 5v level goes down. +5v, +4.8v, +3.6v, +2.9v. It 
remains stable however with just the CPU and the three core memory 
boards, it becomes difficult for the power supply when I add boards in 
addition to these.

- This is definitely not a problem at the level of the Power Fail circuit.
- The big capacitors are not in fault (I rechecked twice).
- So this maybe a problem at the level of the regulation itself, the +5V 
balancing system ?


Question: a faulty voltage regulator can behave in this way? I always 
thought it worked or it did not work, but not between the two states 
depending on the charge.


Anyway, suggestions are always welcome ;-)

PS : I'm starting to want to put another power supply for that regulated 
+5V, and bypass the +5V regulated of G2, but it would be a shame and not 
in the spirit of a restoration in my opinion.





 Forwarded Message 
Subject: 	Re: DCC-116 E / DATA GENERAL NOVA 2/10 / Nixdorf 620 - 
Restoring and restarting

Date:   Wed, 16 Aug 2017 23:33:31 +0200
From:   Dominique Carlier <d...@skynet.be>
To: Christian Kennedy via cctalk <cctalk@classiccmp.org>



Hi !

I finally find some time to work again on my D-116, try to find the
problem(s), thus principally at the level of PSUs.
As you suggested, I inspected particularly the large capacitors of both
power supplies. I replaced those that appeared suspicious according to
the results via my ESR meter, but note that this one is not supposed to
be able to verify the capacitors of more than 22000μF. I have also some
doubt about the results (capacitor working with a real charge or not).

Anyway, unfortunately the problem is still there. I don't know where to
search now. If I understand well, the two power supplies can cause a
Power Fail if one of the regulated voltages were out of range. At this
point I do not know which of the two is in fault, because when the Power
Fail is active the + 5V is automatically dropped around 1.5V.
Following the schematics I have focused my attention on the value of
some resistors with an important role in triggering this state (eg R18).
I found nothing abnormal, I checked all the capacitors, a large package
of resistances.

At this point what I know is that I can simultaneously connect the CPU
board and the three core memory boards without problem. If I add the
controller board for the removable hard disk drive or for the tape ->
Power Fail.
Interesting thing: if I connect only the CPU board and the disk
controller: Power Fail too. Maybe the PSU in default is the one that
supply the + 5V for the boards in the upper part of the rack? (slot 1
for the CPU, solt 4, 5 and 7 for the mem, slot 10 and 12 for tape and hdd)

I can provide pictures, schematics, ...

Regardless of this failure, I try to find information about what I could
install as an operating system on that big beast. If you have too any
ideas about that?

I would like to be able to do simple tasks such as managing files
(copying files from disk to tape and vice versa), being able to create
directories and sub directories, writing text, print on my drum printer,
programming in a simple language such as BASIC, and also, if I find a
communication board (on the CPU-board I don't found any trace of
components that evoke me an RS-232 interface), communicate with another
machine, print on a teletype ... Does this seem possible for you with
this type of machine? If yes, with which OS?

I took tons of pictures of the machine from all angles, I will post them
soon ;-)

Dominique




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.

It's a switcher; look at the caps in the LC filter (downstream of the
series pass transistor) that, together with the inductor, form the
energy storage mechanism of the power supply; check the source supply as
well.  The fact that it eventually comes back suggests that the
reference, comparator and pass device are probably functioning.

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

2017-08-16 Thread Dominique Carlier via cctalk 

Hi !

I finally find some time to work again on my D-116, try to find the 
problem(s), thus principally at the level of PSUs.
As you suggested, I inspected particularly the large capacitors of both 
power supplies. I replaced those that appeared suspicious according to 
the results via my ESR meter, but note that this one is not supposed to 
be able to verify the capacitors of more than 22000μF. I have also some 
doubt about the results (capacitor working with a real charge or not).


Anyway, unfortunately the problem is still there. I don't know where to 
search now. If I understand well, the two power supplies can cause a 
Power Fail if one of the regulated voltages were out of range. At this 
point I do not know which of the two is in fault, because when the Power 
Fail is active the + 5V is automatically dropped around 1.5V.
Following the schematics I have focused my attention on the value of 
some resistors with an important role in triggering this state (eg R18). 
I found nothing abnormal, I checked all the capacitors, a large package 
of resistances.


At this point what I know is that I can simultaneously connect the CPU 
board and the three core memory boards without problem. If I add the 
controller board for the removable hard disk drive or for the tape -> 
Power Fail.
Interesting thing: if I connect only the CPU board and the disk 
controller: Power Fail too. Maybe the PSU in default is the one that 
supply the + 5V for the boards in the upper part of the rack? (slot 1 
for the CPU, solt 4, 5 and 7 for the mem, slot 10 and 12 for tape and hdd)


I can provide pictures, schematics, ...

Regardless of this failure, I try to find information about what I could 
install as an operating system on that big beast. If you have too any 
ideas about that?


I would like to be able to do simple tasks such as managing files 
(copying files from disk to tape and vice versa), being able to create 
directories and sub directories, writing text, print on my drum printer, 
programming in a simple language such as BASIC, and also, if I find a 
communication board (on the CPU-board I don't found any trace of 
components that evoke me an RS-232 interface), communicate with another 
machine, print on a teletype ... Does this seem possible for you with 
this type of machine? If yes, with which OS?


I took tons of pictures of the machine from all angles, I will post them 
soon ;-)


Dominique




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.

It's a switcher; look at the caps in the LC filter (downstream of the
series pass transistor) that, together with the inductor, form the
energy storage mechanism of the power supply; check the source supply as
well.  The fact that it eventually comes back suggests that the
reference, comparator and pass device are probably functioning.

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

2017-05-18 Thread Dominique Carlier via cctalk 

Hi all,

Sorry for this long wait. Because of some family problems combined with 
a big professional project I had to put this project on hold. However I 
intend to continue this restoration with detailed photos and all the 
continuation of the adventure with a lot of informations ;-)


Since my lasts posts on cctalk I received the schematics of a DG Nova 
1200, all the information I needed to repair the power supply are in 
this documentation. However it is a very complex system of voltage 
regulation and because I am not a professional electronics technician, I 
have not yet found the origin of the power loss that results in the 
state of "Power Fail" (To be precise : it is when the computer is 
populated with more than 2 or 3 boards. Any board).


It is also because i have not currently enough time to search the 
problem in "blind mode" : De-solder all the transistors to search and 
evaluate a possible leaking, replace all the suspect capacitor (just to 
replace the big ones it cost more than 200$) etc..


But be patient ;-) I'm determined to continue the adventure soon as 
possible.


Thanks for your interest !

Dominique


On 18/05/2017 05:29, AJ Palmgren 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 
> 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/terminal.jpg

>

http://www.actingmachines.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

>

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:

*17HEX 0 – 15 ENTREX INC 62 00 01842 002 REV A*

*16HEX 16 30 31 ENTREX INC 62 00 01842 002 REV A**
15OPTION 2  Empty**
14OPTION 1  Empty**
13PRINTER   ENTREX INC SN598**
12TAPE 556/800 BPI 2433 LFI 213**
11TAPE 1600 BPI  Empty**
10DISK   2456 00 MP-Kontroller
D44an620 6393500215  2456 7 0 1577**
09COMMO Empty**
08SCANNER  Scanner BD 2431 NCAG 54147.1.15
2431 02394**
07MEM   1609 0 7 02616**
06MEM   Empty**
05MEM   1609 0 8 02367**
04MEM   1615 01 9 5596**
03TTY Empty**
02DO NOT USE Empty**
01C.P.  1509 05 4 04436*

Concerning this I also ask a few questions:

 *

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

2017-05-18 Thread Dominique Carlier via cctalk 

Hi,

I saw this ad but the shipping costs until Belgium decided me to react 
as if I had not seen anything ^^


It's a pity, I would have taken a few boards.


On 18/05/2017 06:05, AJ Palmgren wrote:

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 > 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
> 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/terminal.jpg

>

http://www.actingmachines.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

>

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:

*17HEX 0 – 15 ENTREX INC 62 00 01842 002
REV A*

*16HEX 16 30 31 ENTREX INC 62 00 01842 002 REV A**
15OPTION 2  Empty**
14OPTION 1  Empty**
13PRINTER   ENTREX INC SN598**
12TAPE 556/800 BPI 2433 LFI 213**
11TAPE 1600 BPI  Empty**
10DISK   2456 00 MP-Kontroller
D44an620 6393500215  2456 7 0 1577**
09COMMO Empty**
08SCANNER  Scanner BD 2431 NCAG 54147.1.15
2431 02394**
07MEM   1609 0 7 02616**
06MEM   Empty**
05MEM   1609 0 8 02367**
04MEM   1615 01 9 5596**
03TTY Empty**
02DO NOT USE Empty**
01C.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

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

2017-05-17 Thread jim stephens via cctalk 



On 4/1/2017 6:47 PM, Jay Jaeger via cctech wrote:

Typically not, since with no tape it should act like all the holes are punched, 
yes?
with no tape, the Data Products servo ran open loop.  You'd think what 
you said was true, but IIRC, you didn't run them with no tape.


Later the 2230/60/90s had solid state and it wasn't a problem any more.  
I don't know about this printer, but in the 80's a lot of the printers 
worked similarly to the Data Products.


thanks
Jim

Sent from my iPad


On Apr 1, 2017, at 18:04, Chuck Guzis via cctech  wrote:


On 04/01/2017 01:45 PM, Al Kossow via cctalk wrote:



On 4/1/17 12:33 PM, Dominique Carlier via cctalk wrote:
strange machine, there is a tape reader inside the printer.

it is used to program vertical forms postioning. the format tape is
in a loop


...and whatever you do, don't lose the tape.  There will be
"interesting" consequences the moment some program does a form feed
(skip on channel 1)...

--Chuck

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

2017-05-17 Thread AJ Palmgren via cctalk 
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 
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@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:
>>
>> *17HEX 0 – 15 ENTREX INC 62 00 01842 002 REV A*
>>
>> *16HEX 16 30 31 ENTREX INC 62 00 01842 002 REV A**
>> 15OPTION 2  Empty**
>> 14OPTION 1  Empty**
>> 13PRINTER   ENTREX INC SN598**
>> 12TAPE 556/800 BPI 2433 LFI 213**
>> 11TAPE 1600 BPI  Empty**
>> 10DISK   2456 00 MP-Kontroller D44an620
>> 6393500215 2456 7 0 1577**
>> 09COMMO Empty**
>> 08SCANNER  Scanner BD 2431 NCAG 54147.1.15 2431
>> 02394**
>> 07MEM   1609 0 7 02616**
>> 06MEM   Empty**
>> 05MEM   1609 0 8 02367**
>> 04MEM   1615 01 9 5596**
>> 03TTY Empty**
>> 02DO NOT USE Empty**
>> 01C.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

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

2017-05-17 Thread AJ Palmgren via cctalk 
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> 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:
>
> *17HEX 0 – 15 ENTREX INC 62 00 01842 002 REV A*
>
> *16HEX 16 30 31 ENTREX INC 62 00 01842 002 REV A**
> 15OPTION 2  Empty**
> 14OPTION 1  Empty**
> 13PRINTER   ENTREX INC SN598**
> 12TAPE 556/800 BPI 2433 LFI 213**
> 11TAPE 1600 BPI  Empty**
> 10DISK   2456 00 MP-Kontroller D44an620
> 6393500215 2456 7 0 1577**
> 09COMMO Empty**
> 08SCANNER  Scanner BD 2431 NCAG 54147.1.15 2431 02394**
> 07MEM   1609 0 7 02616**
> 06MEM   Empty**
> 05MEM   1609 0 8 02367**
> 04MEM   1615 01 9 5596**
> 03TTY Empty**
> 02DO NOT USE Empty**
> 01C.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

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

2017-04-04 Thread Christian Kennedy via cctalk 


> On 4/4/2017 7:09 AM, Dominique Carlier via cctalk wrote:

>> Concerning the memory, I analyzed more in detail, I think finally that
>> all the memory is core type, 1 X 16KW (it is marked on it) and 2 X 8KW
>> (according to the size of the core package in comparison with the 16KW
>> board). Thus a total of 32KW.

Yes, that would be a reasonable maximum configuration for this machine.

I yanked the CPU board out of my DCC 116 literally for the
first time, ever, which sent me down a rabbit hole.

Yes, it's a 1200 clone, which surprised me -- but the 1980 date on
the etch of your CPU is quite interesting.  Turns out DCC literally
stole the prints for the 1200 and used it as the basis of the D-116 (the
also apparently ripped off the PDP-8 and PDP-11).  At least in the case
of the D-116 it was literally a case of building to DG's prints, so much
so that the judge in the infringement case told DCC that had they
actually reverse engineered the 1200 they would have prevailed, but that
it was so obvious that they'd just done a punch of the machine that they
had to hand the injunction to DG.

Where this gets interesting is the timing.  DG won the injunction in
September 1975, and it so crippled DCC that DG ended up acquiring DCC
and their product line in 1977 and eventually putting a stake in the
heart of the product line at the end of the 70s.

Does your CPU board have a DCC or DG copyright on it?

Making it stranger is the prohibition on putting anything in slot two
(mine has the same restriction).  I'd have to look closely, but that
suggests that while the design ripped off the 1200 CPU it ripped off the
800 backplane (the 800 CPU takes two slots, the 1200 only one, and
thanks to the way the backplane is wired it's possible to run a 1200 CPU
in an 800 chassis).

Finding a basic I/O board shouldn't be difficult; you only need TTY (not
reader or punch controls), and while it would be nice you probably don't
need the RTC, either.  Still, given the date of your machine the TTY
functionality /may/ be on the CPU card itself.

Is there a DB-9 connector somewhere on the rear bulkhead of the machine?

-- 
Christian Kennedy, Ph.D.
ch...@mainecoon.com AF6AP | DB0692 | PG00029419
http://www.mainecoon.comPGP KeyID 108DAB97
PGP fingerprint: 4E99 10B6 7253 B048 6685 6CBC 55E1 20A3 108D AB97
"Mr. McKittrick, after careful consideration…"

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

2017-04-04 Thread jim stephens via cctalk 



On 4/4/2017 7:09 AM, Dominique Carlier via cctalk wrote:



Concerning the PSU I will analyze your suggestions.

Concerning the memory, I analyzed more in detail, I think finally that 
all the memory is core type, 1 X 16KW (it is marked on it) and 2 X 8KW 
(according to the size of the core package in comparison with the 16KW 
board). Thus a total of 32KW.


For transmission via serial port, unfortunately I do not have this 
"basic board" in slot 3 (TTY), it's empty. Can we still find board 
like this? 
The design is 4 x 74181, which is potentially a 16 bit processor. The 
74181 is a common ALU for systems, can the number of bits of 74181 
adders are frequently an indicator of the width of the CPU.


The Serial port may be elsewhere.  I'd look for RS232 level shifters 
(probably 1488 and 1489s) and a UART on other boards.  You may be out of 
luck, but sometimes the serial may be in another area in systems.


Another sign to follow are the silver cans with oscillators, as they can 
be for the system themselves, or for serial I/O.

thanks
Jim

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

2017-04-04 Thread Dominique Carlier via cctalk 

Many thanks for these detailed answers ! :)


Indeed, I finally do not know exactly what Nova my DCC is the clone. 
Another specialist suggested that it was rather a clone of NOVA 1200?


Note that in Nixdorf contracts for the 600 series, these machines were 
sometimes updated with a new CPU over the years of service.

In the doubt here are pictures of the board in slot 01 dedicated to the CPU:

http://www.actingmachines.com/classiccmp_forum/cpu01.jpg

http://www.actingmachines.com/classiccmp_forum/cpu02.jpg

http://www.actingmachines.com/classiccmp_forum/cpu03.jpg

Do you have any idea what that is?

Concerning the PSU I will analyze your suggestions.

Concerning the memory, I analyzed more in detail, I think finally that 
all the memory is core type, 1 X 16KW (it is marked on it) and 2 X 8KW 
(according to the size of the core package in comparison with the 16KW 
board). Thus a total of 32KW.


For transmission via serial port, unfortunately I do not have this 
"basic board" in slot 3 (TTY), it's empty. Can we still find board like 
this?


Dominique


Er.  My DCC-116 is more a clone of the mapped Nova 840 than the Nova 2,
with the DCC/Keronix "64Kword" hack that gives up more than one level of
indirect memory reference in exchange for having 16, rather than 15,
bits of logical memory reference.

IIRC the functionality of the basic I/O board normally found in slot
three is subsumed into the CPU card of the DCC116, so you should be fine
as long as you can find the signals on the back of the machine.

It's a word oriented machine, so memory is sized in KW, not KB. You can
probably tell how big the boards are by looking at the physical address
jumpers; core boards were typically 8KW, MOS boards were typically 16 or
32KW, depending on vintage. Hint:  The more jumpers, the smaller the board.

I have no idea how this machine packages things, but in jumbo-chassis
Novas the lower PS generates five and 15 volt supplies, the top PS
generates only five.  The reason for this is that the 15 volt supply is
only used by core memory boards and the memory bus is only available in
the lower chassis.

Sounds like one of the +5V switchers is having issues.
+/-5V and +15V but not -15V should be regulated.  In the original DG
power supply both five and 15 volt supplies were derived from a common
+30V unregulated supply, but it's not clear that DCC followed that
model.  It may be helpful to know that the +15V supply is not regulated
to 15V but temperature compensated downward with increasing temperature,
such that at 55C it's closer to 14.4V; this is done to maintain margins
on the core planes. The consequence is that you're probably looking at
something having drifted in the voltage divider that feeds the voltage
comparator or something having drifted in the temperature compensation
stuff (if it's actually there) rather than a simple zener gone bad.

/POWER FAIL is asserted by the power supply itself, as is MEM OK.
It's a switcher; look at the caps in the LC filter (downstream of the
series pass transistor) that, together with the inductor, form the
energy storage mechanism of the power supply; check the source supply as
well.  The fact that it eventually comes back suggests that the
reference, comparator and pass device are probably functioning.


Should be, as long as the machine isn't running in extended logical
address mode (my DCC has a front panel switch to enable/disable this
feature).

Nice job on getting the machine to boot!
Cheers,
Chris

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

2017-04-02 Thread Dominique Carlier via cctalk 

After the mess, ...

http://actingmachines.com/classiccmp_forum/mess01.jpg

... it was time to reorganize a cool place to continue this restoration :-)

http://actingmachines.com/classiccmp_forum/calm01.jpg

http://actingmachines.com/classiccmp_forum/calm02.jpg

Without the schematics of the two power supplies, I decided to follow 
the tracks on the printed circuits boards from the area where I measured 
the collapsed regulated 5vdc, I start to check the components and try to 
understand the problem alone, I decided to check the 5 big capacitors 
this one is a little bit high but OK


http://actingmachines.com/classiccmp_forum/capacheck2.jpg

YES ! I finally found a dead one, hourra!! :-)

http://actingmachines.com/classiccmp_forum/capacheck1.jpg

A 23000µf 15VDC used in the filtering of the regulated 5vdc, but... 
finally no, unfortunately ... it was not the source of the power fail :-/


Tomorrow I continue my investigation and I will check the big capacitors 
of the other power supply in charge of the 15V which is monitored and 
possibly also the cause of the error message.


Dominique

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

2017-04-01 Thread Jay Jaeger via cctalk 
Typically not, since with no tape it should act like all the holes are punched, 
yes?

Sent from my iPad

> On Apr 1, 2017, at 18:04, Chuck Guzis via cctech  
> wrote:
> 
>> On 04/01/2017 01:45 PM, Al Kossow via cctalk wrote:
>> 
>> 
>>> On 4/1/17 12:33 PM, Dominique Carlier via cctalk wrote:
>>> strange machine, there is a tape reader inside the printer.
>> 
>> it is used to program vertical forms postioning. the format tape is
>> in a loop
> 
> 
> ...and whatever you do, don't lose the tape.  There will be
> "interesting" consequences the moment some program does a form feed
> (skip on channel 1)...
> 
> --Chuck

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

2017-04-01 Thread Mark J. Blair via cctalk 
I do not have anything useful to say, but I liked your pictures and video. 
Congratulations on a successful first boot!

-- 
Mark J. Blair, NF6X 
http://www.nf6x.net/

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

2017-04-01 Thread Chuck Guzis via cctalk 
On 04/01/2017 01:45 PM, Al Kossow via cctalk wrote:
> 
> 
> On 4/1/17 12:33 PM, Dominique Carlier via cctalk wrote:
>> strange machine, there is a tape reader inside the printer.
> 
> it is used to program vertical forms postioning. the format tape is
> in a loop


...and whatever you do, don't lose the tape.  There will be
"interesting" consequences the moment some program does a form feed
(skip on channel 1)...

--Chuck

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

2017-04-01 Thread Al Kossow via cctalk 


On 4/1/17 12:33 PM, Dominique Carlier via cctalk wrote:
> strange machine, there is a tape reader inside the printer.

it is used to program vertical forms postioning. the format tape is in a loop

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

2017-04-01 Thread Dominique Carlier via cctalk 

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/terminal.jpg 



http://www.actingmachines.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 



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:


*17HEX 0 – 15 ENTREX INC 62 00 01842 002 REV A*

*16HEX 16 30 31 ENTREX INC 62 00 01842 002 REV A**
15OPTION 2  Empty**
14OPTION 1  Empty**
13PRINTER   ENTREX INC SN598**
12TAPE 556/800 BPI 2433 LFI 213**
11TAPE 1600 BPI  Empty**
10DISK   2456 00 MP-Kontroller D44an620 
6393500215 2456 7 0 1577**

09COMMO Empty**
08SCANNER  Scanner BD 2431 NCAG 54147.1.15 2431 02394**
07MEM   1609 0 7 02616**
06MEM   Empty**
05MEM   1609 0 8 02367**
04MEM   1615 01 9 5596**
03TTY Empty**
02DO NOT USE Empty**
01C.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 



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 



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 




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 



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_2.jpg