Tuesday, October 29, 2019

Entrex Data/Scope Key Tronic 065-01380 PCB-002D Keyboard preserved as refrigerator magnets!

My friend Cprossu has found this instructables.com post for me.

I left a comment for the author, complimenting him on saving this keyboard from the trash, and being so creative with it.  It is [mostly] preserved, even though the reed switches are now removed completely.  But one of the reasons I like this system is because of the terminals, and the keyboards are always one of the best parts of that!

https://www.instructables.com/id/Fridge-Magnet-Keyboard/
 
 

Entrex Data/Scope CRT Replacements - GTE Sylvania 9VADP4

Well, the CRT has "gone to air", with the back neck seal broken off...


Monday, October 28, 2019

The MM5240: Understanding the operation of the Entrex/Nixdorf Data/Scope Keystation





The best description I've come across for how these terminals work:

RaymondHng   [Reformatted by me for ease of understanding]

This is not a dumb terminal. It is dumber than a dumb terminal. It is a data entry key station as part of a key-to-disk system. 

I use to work on a competing product, the UNIVAC 1900 CADE (Computer-Assisted Data Entry) system. 

Unlike dumb terminals that have some logic of encoding key strokes into ASCII characters, sending the ASCII characters to the computer, receiving ASCII characters from the computer, storing the ASCII characters in its internal RAM, and displaying the ASCII character on the screen, data entry key stations have no ASCII encoding ability and no internal RAM storage. 

A portion of RAM on the central computer serves as storage for each key station's display. 

Sunday, October 27, 2019

Reading AM2708DC EPROMs on the Scanner Board

On the Nixdorf 620 system owned by the Heinz Nixdorf MuseumsForum in Paderborn, Germany, the Scanner board in slot #5 contains two AM2708DC EPROMs.

vs
Of course, we must read these EPROMs!

According to: https://museo.freaknet.org/en/eprom-2708/

[Translated from Italian to English] To read the EPROM 2708, power it with -5V to the VBB pin (21), +12 V to the VDD pin (19), + 5V to the VCC pin (24) and placing the VSS pin (12) to ground. Then the Not Chip Select pin (20) and the programming pin (18) must be connected to ground. At this point it is sufficient to write the memory address to be read into the indexing bus (A0 ... A9), wait for the output signal to settle (according to the datasheet at most 450 ns) and read in the data bus (Q0… .Q7) the data read.

Everybody else talks about using 2716s in systems that are designed to use 2708s, which is in essence the opposite of what I want to do right now, yet still different.  I just want to accurately and safely read a 2708.

Could it be as simple as building a chip socket adapter, and applying constant +5v, -5v and +12v to the pins 24, 21 and 19 respectively, then setting the MiniPro TL866 to read an AM2716 chip, and click go?

Maybe I should lift/isolate pin 18 as well, so programming can't accidentally happen?

Also reference http://www.jrtwine.com/jtwine/arcade/EPROMRef.htm
Other threads about using 2716s in systems designed for 2708s:
(which is roughly the opposite of what I wish to do...)

http://www.vcfed.org/forum/showthread.php?23603-2716-to-2708-conversion&p=165483#post165483

and

http://compgroups.net/comp.os.cpm/question-on-eprom-programmers/945291


Entrex Data/Scope turned Commodore C116


On 18/10/2019 09:55, Andreas wrote:
Hello...,

I found your page
-https://entrex480.blogspot.com/p/nixdorf-620-restoration.html-

with the help of Philipp Maier. -www.diskettenschlitz.de-  in my
collection I've an old 620 Terminal. In the 1980 I used this monitor
with an enbedded commodore c116. I through out the keyboard and build
in the commodore. Now I tried to restore this system, but the terminal
has a problem with the vertical distraction. Do you have the wiring
diagram for the Terminal?

If your are interested I'll send you some photos.

Best regards

Andreas Stamer
Wolfenb├╝ttel, Lower Saxony

Entrex Datascope PS Serial # 325625
 
UPDATE 2019-10-27:  After having a lovely conversation with Andreas over Skype, I was able to confirm that, alas, decades ago he did indeed discard the terminal motherboard and keyboard from this Entrex Data/Scope - Nixdorf terminal.  As we can see in the first picture, he replaced both, in a VERY creative fashion, with the full Commodore C116 computer.  But I'm glad to know that he has at least preserved the items shown above.

Andreas also provided a picture of the box of Nixdorf floppy disks below, and even though I haven't been able to receive full confirmation, I believe that he included these only because they are branded "Nixdorf", and not because they had any connection with the original Entrex 480/Nixdorf 620 system, or any components thereof.

Monday, October 14, 2019

diskettenschlitz.de & runningserver.com Entrex / Nixdorf Data Scope Terminal

 
 
[Translated from German to English] This is one of the legendary Nixdorf terminals for Nixdorf mainframes. The terminal dates back to the time when Nixdorf was still an independent company. It has a 9-inch black and white picture tube which is covered with a yellow color filter and a thin wire mesh. This is a terminal from the 70s where computers were still huge expensive machines. The purpose of such terminals was to bring the computing power of the mainframe computer to the user's desktop. The terminal thus served as a remote control for the mainframe computer. Today, where personal computers have become small and cheap, the terminal mainframe concept has gone out of fashion. Central mainframe (nowadays, rather, the term "server") 

Unfortunately, this terminal is a wreck, on the one hand, the electronics are incompatible with today's Linux / Unix servers and probably have problems with the memory, as it outputs only a par confused characters. On the other hand, the chassis of the monitor is heavily rusted and the electronics of the monitor is no longer working properly.During the last test I noticed that the picture tube at the back glows blue. A sure sign that it has drawn air.  Since the whole thing is in the bucket, I will I think about what I will do. You could equip the keyboard with a microcontroller and replace the monitor with something new.

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