View Full Version : Help me with my Data General terminal

April 18th, 2009, 05:11 PM
Hi, like I said in my introduction post, I just bought a Data General Dasher d200 terminal, but it isn't working. When I turned it on it didn't do anything, but I found a blown fuse, I replaced the fuse and now when I turn it on it makes a quite buzzing and then it beeps. But the monitor still does not turn on. After reading a another topic about a terminal with the same problem I'm pretty sure the problem is the flyback transformer, but what I don't know is where to get a replacement, the number on top of it is 104-239 and under that is k9x1. I checked ebay and some other websites that have flybacks, but I couldn't find that one. Anybody know where to get a new one, and also any idea what this terminal is worth? BTW, I but this terminal for 2$, a panasonic dot matrix printer for 1$, and a whole stack of computer related books for free at a flee market.

April 18th, 2009, 05:15 PM
Most of the book in the last picture were free, bu a few of them I already had.

April 18th, 2009, 05:30 PM
That's a nice-looking terminal! The fact that it beeps would suggest it's running, which is a good sign. The fourth picture does look a bit worrying though - is that a scorch mark in the middle of the PCB?

It could well be the flyback, but there are other things you can check. What do you have as far as test equipment goes and do you have any documentation (e.g. a service manual)? Can you confirm power is getting to where it should be (esp. to the CRT)?

Not knowing your level of experience, I guess I should issue the standard warning about working on CRT equipment: there's a lot of high voltage to be found in these things, so make sure you know what you're doing before poking around in there.

April 18th, 2009, 05:47 PM
As far as test equipment goes, a multi meter is about all I have.
And yes that is a scorch mark but the traces seem to be intact but I don't know if any else there is fried. And for experience, I'm in the middle of restoring an arcade machine, so I have a fairly decent idea of what I'm doing, but I'm no expert. Another thing I'm wondering is what exactly does a terminal do? I know they hook up to a mainframe, but what can they do by there self. I don't have any manuals or anything. I tried to find one online but I couldn't find anything.

April 18th, 2009, 08:31 PM
By themselves, they don't do much of anything.

If you hit the right key combination (I have no idea for that terminal), you could bring up the setup screen on most terminals.

To check if the flyback is any good, if you have one of those neon bulb voltage checkers, hold the bulb up near the flyback , with the unit on (don't get TOO close to it or you'll find yourself laying on the floor across the room) and, if the bulb lights up (you don't have to do anything with the leads on the tester) then the flyback is operational. BTW, when you do this, remove your watch and any rings, they can heat up pretty quickly in a RF field.

To test the CRT, first see if you can see a glow from the back of the tube neck (this works best in low light) and then put the back of your hand near the face of the CRT. If the hair on your hand stands up, it's working too.

That scorch mark look like something might have been overheating for quite a while. Lick your finger and touch the chips in that area and see if any of them turn the saliva instantly into steam. The hot one will be the problem.

April 18th, 2009, 10:38 PM
Here's a start (http://vt100.net/dg/d411-um/) with the user's manual for the 411 Dasher.

April 19th, 2009, 12:38 AM
Another terminal the DEC vt320 is notorious for blowing its flyback. I've seen a few blown flybacks and you can easily tell if they are goners, they are cracked and leaking gooey fluids.

I guess there are other ways a flyback can fail, have you read something specific about the dasher flyback?

Also a word of advice. BE CAREFUL. The flyback produces a very high voltage and will hurt you if you touch it in the wrong places.

April 19th, 2009, 07:31 AM
HOLY CRAP!!! IT'S ALIVE!!!!!!!! :shock::shock: I don't why it is, but it is! I tried the voltage tester near the flyback, and it didn't lite. Then I tried the wet finger on the chips, and none of them were warm. but then I turned it of and on again, and there were letters on the screen! I plugged the keyboard in and it started typing 0 again and again! My only guess is there was a cold solder on one of the chips, and touching it was enough to make it work. Pics are on there way.

April 19th, 2009, 07:59 AM
Good to hear it's working already - now you just need a Nova to hook it up to and you're all set ;-)

Might be worth popping the PCB out though, giving it a once over for cold solder joints, and reflowing any that look suspicious.

April 19th, 2009, 08:45 AM
Great to hear your terminal is working. There's nothing like the feeling of bringing one of these old machines back from the dead. I love the look of that terminal. So retro and modern at the same time.
As far as what you can do with a terminal. Input and receive information to and from a host computer such as an old S-100 computer, mainframe or minicomputer. Unlike the PC's we use today there was no video card inside the main computer. Character information is transmitted and received in a stream of bits (serial format) via a serial port. Your terminal will need to be hooked up to a standard serial port on a host computer. Some terminals also have built-in modems and can remotely access mainframes. It may have the ability to connect a printer and use it like an electronic typewriter.

April 19th, 2009, 09:36 AM
Well It's getting there but not quite working yet. Like I said it keeps typing 0. I took the keyboard apart and cleaned it up, but even now with all the keys off of it, it still just types 0. If I (with your help of coarse) can get it working, it would be great to be able to at least print with it. One of the books I got with it is about the "8086 Family", so I guess that's the computer it was used with. It would be nice to reunite it with an 8086, but I have no idea what that would cost (I think it's a minicomputer). Another thing I got with it is a "Data Base Monthly" from February of 1984. And inside of it there is an add for Data General computers, and a coupon for free "Desktop generation Manual". The coupon has been cut out. Probably lead to the purchase of the D200 that I have. I almost forgot to mention now it only beeps when the keyboard is not plugged in, I don't have a clue why.

April 19th, 2009, 11:18 AM
Well It's getting there but not quite working yet. Like I said it keeps typing 0. I took the keyboard apart and cleaned it up, but even now with all the keys off of it, it still just types 0.

I suggest that you may have to do a little studying on how keyboards work before proceeding. You may have a contact that is stuck in the close position, a solder bridge or even a bad keyboard decoder circuit. Someone more familiar with the troubleshooting may be able to help.

It would be nice to reunite it with an 8086, but I have no idea what that would cost (I think it's a minicomputer).

An "8086" is an Intel CPU chip and was used in personal computers in the early to mid 80's. It is not a standalone computer. Also, minicomputers usually did not use this chip. This terminal should have the ability to connect to a number of different computers. No need to limit yourself to 8086 based units.
The system software on the host computer you use must be able to interpret the binary code generated by this terminal. Terminal manufacturers used different coding schemes that are not compatible with each other. However most terminals have the ability to "mimic" the more popular ones. DEC VT100 and TTY are some of the more common. There is a setup routine that is called up by some key sequence that gives you a menu and allows you to select what terminal you want to "emulate" and the transmission protocol(baud rate, stop bits, parity, etc.). Try and find a User's guide if you can or at least the key commands you need to operate it.
A good example of how to setup a terminal is a free communications program that comes with Windows called Hyperterm. This utility allows your PC to become a "dumb" terminal but in a window. Launch the utility by going to Start->All Programs->Accessories->Communications-> Hyperterm. The first menu you will have to give the session a name(any one will do). For all the rest accept the default settings. Once your past the initial setup menus look for a dropdown list and open it up. You will see the more common terminals listed. Once your through examining things, exit and don't save.

April 19th, 2009, 11:34 AM
The Dasher series of terminals (not to be confused with DG's Dasher PCs) were one of the many low-cost terminals that saw general use. The most likely place to find one of these would be connected to a DG Nova or Eclipse mini. I suspect yours was most likely hooked to a 8086 development system, based on the other books you have.

I'll agree with the previous poster on keyboards. They can be a pain in the neck as they age. Yours at first blush looks like one that uses foil-capped foam-rubber-backed capacitive sensed pads. Most likely, the foam's started to (or has) deteriorated, causing one or more keys to appear stuck. I could be mistaken, as it's hard to tell from your photo.

You can make new pads for these keyboards; there are a couple of sites on the web that give details on doing it. I'd probably abandon hope of finding an OEM replacement kit for the D200, though you never know.

Here's a repair guide for Apple Lisa keyboards (http://lisafaq.sunder.net/lisafaq-hw-kb_repair.html) which look to have the same mechanism as yours. It should be noted that the Lisa foil contacts are not conductive, but other older keyboards do use naked conductive foil. A simple probe with an ohmmeter on your old ones will tell you what's what.

April 19th, 2009, 12:34 PM
An "8086" is an Intel CPU chip and was used in personal computers in the early to mid 80's
:oops: The other day I was looking at this computer and I thought it might have been related.http://www.old-computers.com/museum/computer.asp?st=1&c=389
I checked out Hyperterm but I honestly have no idea what I'm doing, I'll look at it closer later.
Thanks for the link Chuck(G), your right, they are foil capped foam, and the foam is disintegrating, but sadly that isn't the only problem. They keyboard still doesn't work even when (picture 21) is taken completely off the board. Another thing to add to the confusion is, when I unplug and plug back in, or wiggle the plug that connects the keyboard to the computer, random letters come up on the screen.

April 19th, 2009, 02:23 PM
Sorry, I read right over the part about the recurring "0" problem but, hey - displaying anything at all is progress!

:oops: The other day I was looking at this computer and I thought it might have been related.
Well, you're not a million miles off. The IMSAI 8080 used an earlier Intel processor (the 8080, hence the name) and you could most certainly connect a terminal to it for use as a console.

They keyboard still doesn't work even when (picture 21) is taken completely off the board. Another thing to add to the confusion is, when I unplug and plug back in, or wiggle the plug that connects the keyboard to the computer, random letters come up on the screen.
It's probably not designed to be plugged in and out like that with the power on, so a few random characters would not necessarily be unexpected. A gentle wiggle on the connector should however not result in such behaviour so you might want to check for a loose connection or oxidisation there.

Do you still get the "0"s when the keyboard is disconnected completely before powering up? If not, how about sticking your meter across the pads for the "0" (or is it the letter "O"?) to see if they're shorted?

April 19th, 2009, 03:42 PM
First of all, it is a zero not o. Second, I cleaned the plug for the keyboard, still just 0s, but I have to actually unplug and plug it back in to get the random letters now. When I turn on the terminal without the keyboard plugged in It just displays this.(attached pic) But as soon as I plug the keyboard in the 0s start coming back. And I checked for a short but there wasn't one. Btw, I found this on ebay. http://cgi.ebay.com/Imsai-8080-w-2-5-25-floppy-drives_W0QQitemZ140314390369QQcmdZViewItemQQptZLH_ DefaultDomain_0?hash=item140314390369&_trksid=p3286.c0.m14&_trkparms=72%3A1205%7C66%3A2%7C65%3A12%7C39%3A1%7C 240%3A1318%7C301%3A1%7C293%3A1%7C294%3A50
Too bad it's already at least 850$ more than I can spend.

April 20th, 2009, 08:41 AM
Today I'm going to resolder some things on the keyboard. I'll post the results.
edit Well, I just finished soldering, it didn't make any difference. I'm really hoping one of you can suggest what to try next, cause I'm clueless right now.
I checked it with the multi meter, it is the capacitive sensing kind.

April 21st, 2009, 05:04 PM
Come on, someone has to have some idea of how to fix it.
I've tried all I can think of, and still no luck.
My only remaining guess is that there is something wrong with one of the IC's or resisters or something like that. But I don't know how to test any of them.

April 21st, 2009, 06:35 PM
maybe that scorch mark has something to do with it?

April 21st, 2009, 11:51 PM
I've tried to search for a manual online, but so far I have not come up with anything useful.

Terminals usually want their keyboard attached and they perform a small self test procedure each time they are turned on. The letters/digits you see are probably from the self test routines.

You mention that characters appear when you jiggle the cable. Maybe you should check that the connectors are good, what do they look like?

April 22nd, 2009, 02:10 AM
Unless you can dig up some documentation or happen to find someone who know's these things well, it's difficult to help you fix this without seeing it.

That said, it would appear the problem is either the keyboard itself or the interface for this on the main board. If you're not able to test any of the parts, you're pretty much limited to visually checking components along these lines.

Maybe you should enlist the help of a professional technician? I know a few hang out here, but I'm not sure if there are any near you. What you'd need is somewhere that can do proper fault diagnosis and repair, as opposed to the board-swapping shops that are commonplace these days.

April 24th, 2009, 06:11 AM
YAY! I don't how or why, but it works! Yesterday I was checking the resisters on the board, one or two of them were not to good but there were close. But then I
Pluged the keyboard in and NO MORE ZEROS! I quickly put the keyboard back together (fist taking off all the bad foil pieces). And somehow it works! I guess there was a cold solder on there somewhere that I missed before somehow. About half of the keys are working right now, and all the rest should be working soon. Now you're right, I need a Nova to go with it.:rolleyes: Btw, the scorch mark is right under the anode on the moniter tube, and from pictures I've seen of other ones, there should be a heat shield there.
Thanks everybody for your help and for looking for a manual. I found a website about someone who owns a Data General Nova and has this same terminal with it. I'll probably email him and see if he know how to get to the setup screen (if there is one on this terminal). I'll have a couple pictures of it working later today.

April 27th, 2009, 03:27 AM
Congratulations! and good work

April 27th, 2009, 06:37 PM
Thanks Pontus. Here is a picture, I might post some more but I have to figure how to make them smaller. Sorry it took so long, but I fixed the keys first. I used 3 layers of double sided mounting tape to replace the foam.

April 27th, 2009, 06:52 PM
Yeah! I really love the looks of that terminal. Nice!

April 28th, 2009, 05:32 AM
Thanks Pontus. Here is a picture, I might post some more but I have to figure how to make them smaller. Sorry it took so long, but I fixed the keys first. I used 3 layers of double sided mounting tape to replace the foam.

Neat!. I also like the leather cover you have for your C128 (i think it's a C128)

April 29th, 2009, 06:52 PM
Yup, It's a 128. Heres a picture of how I fixed the keys. I didn't remember to take any pictures when I was doing it but here you can see the three layers of tape and the sharpened pipe I used for cutting the tape, it took forever to do but it worked great.
BTW I posted a bunch of pictures in my album.

June 13th, 2009, 01:19 AM
I love dumb terminals. Who doesn't?

I've had my share of 3 dumb terminals, and ran into a 4th one.

Unfortunately, they all did not have original keyboards.

Obviously, they had proprietary keyboards for themselves, because when I tinkered with the ones I had, using an IBM clone keyboard, they would not respond with characters I assumed it would.

Getting the serial protocol and speed it wanted was hit and miss as well.

I did get some weird characters eventually, and double characters meaning it was decoding both the keypress and release scan key codes I was feeding it.

Obviously this would've taken something more, like maybe a BASIC Stamp converter in between to change the scan codes into it's native tongue.

The 4th dumb terminal I found was a WYSE terminal at a junk store. If I get five bucks and it's still there in a few days I might pick it up, but it had a REALLY weird keyboard port. I think it was a DIN 8 or something connector, not a 5-pin DIN like the old XT keyboards. I would have a hard time getting that to work with anything without that keyboard language translator device.

I don't think I'll be getting it.

I did however, do some experiments using my DOS computer as a dumb terminal. I'm going to make some graphics editors that work with two computers at once like the old Lucas Arts setup was. Fancy hi-res terminal networked locally to a dumb terminal for mundane text rendering and menus.

People still use 2nd generic monochrome monitors for CAD drawing. I did in college for a class. It wasn't dumb terminal anything, but you get the point that they used the lower class tech for the generic crap to save screen area on the fancy one.

Congradulations on your terminal working. It looks very 70's-ish. You should find some amusing toy that emulates a ""SUPER HIGH NEW FANGLED program from that time, or something like Eliza hosted from another computer.


June 13th, 2009, 01:26 AM
When ever I start a new major project, I usually include code to emulate a standard ANSI window for displaying either amusing dated graphics and stuff, or as an easy way to add a console to output raw data to when debugging or editing script functions of stuff..

Blah blah blah..


I keep thinking of Austin Powers and somebody behind the desk having one of your terminals now.. hahahha

P.S. I've seen dumb terminals (10 years ago) that had a current loop BNC type connector on it for connecting to the network (mainframe). Does anyone know how these type of connections work exactly and how to interface with something modern today? I assume it's probably a twisted pair type thing as RJ-45 works now, with a positive and negative swing, but I'd like some specifics. I don't wanna just guess and wonder for the rest of my retro-loving life.


June 13th, 2009, 03:13 AM
P.S. I've seen dumb terminals (10 years ago) that had a current loop BNC type connector on it for connecting to the network (mainframe)

It could have been an IBM 3270


They work quite differently from rs232

July 8th, 2009, 03:15 PM
Are you still looking for schematics?

I have a set for the main board, but not the keyboard.

I also have a user manual.

I can scan them, but it may take a few days. The keyboard is stupid simple...it's capacitive, scanned under control of the 6802 processor, which shifts a "1" into a shift register on the keyboard, then looks to see if a pulse comes out. The shift register connects to the [rows? columns?] and the sense register connects to the other. Pressing a key causes the metallized mylar on the foam to act as a capacitor connecting row and column. The ICs are all marked with DG's proprietary numbering scheme, but, for the most part, they're standard TTL and CMOS parts.

I worked on the design of the D100/D200, so I know lots about the digital side and not much about the analog side.

July 8th, 2009, 03:27 PM
That VDG sticker on the back means the terminal was once DG property :-)

The dark spot on the PCB under the CRT anode connection is probably just dust accumulation, attracted by static electricity from the anode cap. By the way...DO NOT TOUCH THAT ANODE CAP. If you need to remove it, use a long screwdriver, grounded to one of the "gold" spring wires that holds the upper half up. Slide the screwdriver under the rubber cap, until you hear a SNAP, then it's safe. Of course, you do all that ONLY after unplugging the terminal!

In retrospect, that was a very poor location for the high voltage anode cap...right above the sensitive logic board :-)

July 8th, 2009, 03:35 PM
The foil pads on the keys are *not* conducting...there's a thin insulating layer over the foil. They work by capacitively coupling a pulse from one half-moon pad to the adjacent one.

July 8th, 2009, 03:41 PM
There's no set-up screen on the D200, baud rate and parity are set on the rear switches.

To go online, use CMD-Online. The rear DB-15 is wired conventionally. You'll need to tie the modem control lines together - DTR to (DSR, CD and CTS) and use pin 7 for GND, and 2 & 3 for TX and RX. Standard RS-232 connections, but modem signals have to be satisfied.

You should be able to talk to it from a PC.

July 9th, 2009, 04:45 AM
Contact me if you need schematics or reference manual for the D200:



August 4th, 2009, 05:02 PM
Hi All;
For Schematics and Info .. Look up Bruce Ray of WildHare Computers fame .. He is the main Source for Data General Stuff... He is not at home right now , But he will be back after the middle of the Month , if you don't hear from Him... :) :)

December 5th, 2010, 05:21 AM
If you have schematics for the D400 I’d be interested.

My Data General (http://www.foxdata.com/blog/)blog.

December 6th, 2010, 02:47 PM
Hi xyzzy!

Welcome to the forums :) Nice to see that Torbjörn got you the terminal! Did it work?

December 7th, 2010, 12:00 AM
No, unfortunately not.

Hi xyzzy!

Welcome to the forums :) Nice to see that Torbjörn got you the terminal! Did it work?

December 7th, 2010, 05:18 AM
All I can find is this:


Only the users manual

December 7th, 2011, 08:35 AM
Hi ka1axy,
I'm looking for schematics of a Dasher D200.
We still use one at work with a Data General Eclipse. It's used in a test station to test one of the systems on the B1 bomber. The terminal stopped working.
Can you help?