Use other "greyscale" monitors with mono systems?

Has anyone been able to use other greyscale monitors in place of the next ones on the mono systems.  I am not talking about a color vga monitor, but a dedicated greyscale monitor.  The reason I ask is that I have a couple of pixelink xds120 greyscale monitors in storage, and I know others like cornerstone created monitors like this.  I cant find any specs for it on google, but does anyone think this might be something that could work?

Will post more info on monitors when I can dig around and find them.

Chef

I have been "studying" this subject for years.
NOTHING ELSE will work correctly :!:  :!:  :!:

Quote from: "kenjay"I have been "studying" this subject for years.
NOTHING ELSE will work correctly :!:  :!:  :!:

Same here.  I have been considering looking for a source for the CRT tubes used in the N4000a monitors.  I had sourced them several years ago but have misplaced the notes.  It seems like it was a company in the northern US that priced them in single lots at around $85.  As I recall it was a Toshiba tube.   Maybe I should crack one open and see if I can find a part number for the tube.

Quote from: "kenjay"I have been "studying" this subject for years.
NOTHING ELSE will work correctly :!:  :!:  :!:

I was afraid of something like that.

Was it someone in here who said he had got a sort of picture on a color crt by sending the gray signal to all the color pins on a vga connector.  May have been somewhere else, as I have read quite a lot lately, and it all starts turning to mush in my head.

Chef

Quote from: "nextchef"

Quote from: "kenjay"I have been "studying" this subject for years.
NOTHING ELSE will work correctly :!:  :!:  :!:

I was afraid of something like that.

Was it someone in here who said he had got a sort of picture on a color crt by sending the gray signal to all the color pins on a vga connector.  May have been somewhere else, as I have read quite a lot lately, and it all starts turning to mush in my head.

Chef

That was mentioned on usenet and on the old forum but no one to my knowledge has got past the ghosting problem with a VGA monitor.

Quote from: "blackcube"

Quote from: "nextchef"

Quote from: "kenjay"I have been "studying" this subject for years.
NOTHING ELSE will work correctly :!:  :!:  :!:

I was afraid of something like that.

Was it someone in here who said he had got a sort of picture on a color crt by sending the gray signal to all the color pins on a vga connector.  May have been somewhere else, as I have read quite a lot lately, and it all starts turning to mush in my head.

Chef

That was mentioned on usenet and on the old forum but no one to my knowledge has got past the ghosting problem with a VGA monitor.

How bad is the ghosting?  I guess it is too annoying to use, or people in here would be using it.

Chef

Quote from: "nextchef"

How bad is the ghosting?  I guess it is too annoying to use, or people in here would be using it.

Chef

I've never see it myself, just read about it.  I have 4-5 good clear bright monitors so at the moment, it's not an issue with me.  I have considered installing the kill switch from usenet to allow me to run my Cube 24/7 but conserve monitor life.

Quote from: "blackcube"That was mentioned on usenet and on the old forum but no one to my knowledge has got past the ghosting problem with a VGA monitor.

I would guess that the ghosting problem is because the signal is coming down one line and then splitting into 3, thus if blue arrived at a different time than red and/or green then you would get ghosting.  Considering how fast a monitor scans it would only need to be the smallest fraction of a second and you would get the problem.  Think of it like FM multipath distortion.  Maybe also red is poisoning (kind of like a feedback) green, and blue and vice versa as they are all connected together, perhaps using a few diodes would prevent signals feeding back into each other.

When I was on my exploits into trying to get my TFT working with NeXT I recall I read a monitor service manual, maybe a DEC one that said if you want to connect a mono monitor to a color computer you connect green only, reverse that and you connect mono out to green in on a colour monitor.  Perhaps this also explains why we have SOG on not sync on red or blue?.  I don't have mono so I can't test it but I'd think it would be worth experimenting.  As far as I know so far people have tried to interface to color monitors.  Should it not be a lot easier trying with a mono monitor?

Quote from: "brams"

Quote from: "blackcube"That was mentioned on usenet and on the old forum but no one to my knowledge has got past the ghosting problem with a VGA monitor.

I would guess that the ghosting problem is becuase 1 signal is coming one line and then joining into 3, thus if blue arrived at a different time than red and/or green then you would get ghosting.  Considering how fast a monitor scans it would only need to be the smallest fraction of a second and you would get the problem.  Think of it like FM multipath distortion.  Maybe also red is poisoning (kind of like a feedback) green, and blue and vice versa as they are all connected together, perhaps using a few diodes would prevent signales feeding back into each other.

When I was on my exploits into trying to get my TFT working with NeXT I recall I read a monitor service manual maybe a DEC one that said if you want to connect a mono monitor to a color computer you connect green only, reverse that and you connect mono out to green in on a colour monitor.  Perhaps this also explains why we have SOG on not sync on red or blue?.  I don't have mono so I can't test it.  But I'd think it would be worth experimenting.  As far as I know so far people have tried to interface to color monitors.  Should it not be a lot easier trying with a mono monitor.

That makes a lot of sense to me.  I should look for a  monochrome VGa monitor to try it on.

From what I have found, one of the "features" of the greyscale monitors is that they usually have a higher dpi than a standard color vga monitor.  I found some docs for the pixelink I have, and it touts that it is 120dpi high resolution.  I also remember cornerstone touting the "high resolution" of their gs displays as well.  I assume that the NeXT monitor would be similar?  I do not know how monitors work in detail, but could it be that the color VGA monitor can not properly display/focus the higher res signal from the nextstation.

Chef

Quote from: "brams"When I was on my exploits into trying to get my TFT working with NeXT I recall I read a monitor service manual, maybe a DEC one that said if you want to connect a mono monitor to a color computer you connect green only, reverse that and you connect mono out to green in on a colour monitor.  Perhaps this also explains why we have SOG on not sync on red or blue?.  I don't have mono so I can't test it but I'd think it would be worth experimenting.  As far as I know so far people have tried to interface to color monitors.  Should it not be a lot easier trying with a mono monitor?

That would make the image all green then, right?  Might be kind of funky to do it that way, sort of like an old mainframe terminal display.  I would prefer all blue if I had the choice.

Chef

Quote from: "nextchef"That would make the image all green then, right?  Might be kind of funky to do it that way, sort of like an old mainframe terminal display.  I would prefer all blue if I had the choice.

Chef

If you connected the mono out to green I assume it might be I've assumed a lot in the past and been wrong, so for what it would take to try it which is not a lot, I'd be up for experimenting, especially today (Sunday) as I'm a bit bored and eBay usually beckons when I'm bored........  The other way around might work OK outputting green into a mono monitor but that not what is needed.

I'd get an old high res mono monitor and experiment with that, not sure what might be suitable, maybe a DEC one?

I personally feel that as all wires are connected to each other R G & B on the monitor to the mono signal that they are feeding back into each other, for what it would cost, get a handful of small diodes, put one on each wire and try it.

I saw a non NeXT display used with the Mono NeXT.

If I remember this was a prototye and never made it beyond that.

I do not have any additional information.

This was in the early 90's.

Hi all,

I have successfully connected a plain VGA multisync monitor (17 inches Olivetti brand with Sony CRT) to my NextStation Mono via BNC connectors. It works fine, no ghost images. As soon as I find time, I will provide a few pictures. Next step will be to connect a TFT display. I have an old 16-inch IBM display (IBM 9516-B23 TFT), which I already use for SUN (SparcStation 20), IBM (RS 6000/7011-44), SGI (Indy 4600, Indy 5000), DEC (VAXstation 4000-90) and Commodore (Amiga 2000) computers. It is not a high quality screen, viewing angle and brightness are quite limited. However, it does Sync-On-Green and works with virtually all machines that I could find so far.

Unfortunately, a problem remains - maybe somebody can help:
Originally, mouse and keyboard are connected to the Next monitor. As I do not have the Next monitor, I have no input devices for my NextStation Mono! On Color Stations this should not be a problem because input devices are connected via Soundbox anyway. Maybe I will try to connect a Soundbox with my Mono Station. Does anybody have an experience with that?

Best regards,
Günther

w2510a, what kind of adapter did you use?  Something off the shelf, or that you had to fabricate yourself.  More info please, and pics would be great.

Chef

This is exciting! Please post some pics soon.  Maybe I will be able to use my monostation  :D

Hi all,

I made the adapter myself, just a quick-and-dirty hack, even without any printed circuits (just "on the fly"). There is an FAQ describing the DB 19 pinout and the trick to power up the Next, please search in Google for the keywords "kwellsch next monitor"). I just connected DB 19 PIN 10 (video) with the R, G, B input of my XGA monitor (3 BNC input connectors), PINS 8 and 9 with the appropriate sync inputs and implemented the power on switch as described in the FAQ (i.e. a push button between pins 6 and 19).
Everything works fine now, except the missing input devices ;-(

Quote from: "w2510a"Hi all,

I made the adapter myself, just a quick-and-dirty hack, even without any printed circuits (just "on the fly"). There is an FAQ describing the DB 19 pinout and the trick to power up the Next, please search in Google for the keywords "kwellsch next monitor"). I just connected DB 19 PIN 10 (video) with the R, G, B input of my XGA monitor (3 BNC input connectors), PINS 8 and 9 with the appropriate sync inputs and implemented the power on switch as described in the FAQ (i.e. a push button between pins 6 and 19).
Everything works fine now, except the missing input devices ;-(

And here are the images:



As you can see - quick and dirty, but it works!

Thanks for the pics, as they seem to make things a little clearer, at least for me.  Can you snap a pic of the monitor in action, so we get an idea of what one can expect from this setup?

So the next thing to do would be to wire up the remaining wires to the proper pins on another DB-19 male connector so you could connect to a soundbox.  Then the sound, keyboard and mouse connected to it should work.  I guess you would then not need the switch, as the power button on the keyboard would perform that function.

Very interesting indeed.  Gonna have to go by Gateway Electronics and get me some connectors.

Chef

Quote from: "nextchef"Thanks for the pics, as they seem to make things a little clearer, at least for me.  Can you snap a pic of the monitor in action, so we get an idea of what one can expect from this setup?

So the next thing to do would be to wire up the remaining wires to the proper pins on another DB-19 male connector so you could connect to a soundbox.  Then the sound, keyboard and mouse connected to it should work.  I guess you would then not need the switch, as the power button on the keyboard would perform that function.

Very interesting indeed.  Gonna have to go by Gateway Electronics and get me some connectors.

Chef

I'm surprised this works as well as it reportedly does, IDC/ribbon  cables are not really suited to HF video signals.

Quote from: "brams"I'm surprised this works as well as it reportedly does, IDC/ribbon  cables are not really suited to HF video signals.

I am not an electrical engineer by any means, but is it possible that his cable choice has dampened the signal down enough to keep from getting the ghosting problem others have experienced?  Hopefully a pic can be posted of the screen in action, so others who have tried this can compare and contrast with their results.

Chef

Quote from: "nextchef"I am not an electrical engineer by any means, but is it possible that his cable choice has dampened the signal down enough to keep from getting the ghosting problem others have experienced?  Hopefully a pic can be posted of the screen in action, so others who have tried this can compare and contrast with their results.

Chef

Me neither, and I guess anything is possible, that much I know having seen all sorts of strange things that break the rules.  Some kinds of cables SCSI and Video spring to mind as well as some of the esoteric Hi-Fi interconnects have certain capacitance values for whatever reason.  Video cables for monitors are supposed to be I think about 75Ω resistance.  I suppose it's kind of obvious if you look at a decent cable you can see that are usually unbalanced, shielded co-axial cables.

I think my take on this would be, use a decent BNC cable, whack the end of and put a DB-19 or whatever it is that fits on the back of the NeXT and then make a Y cable out of whatever (an old PC floppy cable) to the Soundbox.  Kind of like an homebrew codged together Y cable

Quote from: "brams"

Quote from: "nextchef"I am not an electrical engineer by any means, but is it possible that his cable choice has dampened the signal down enough to keep from getting the ghosting problem others have experienced?  Hopefully a pic can be posted of the screen in action, so others who have tried this can compare and contrast with their results.

Chef

Me neither, and I guess anything is possible, that much I know having seen all sorts of strange things that break the rules.  Some kinds of cables SCSI and Video spring to mind as well as some of the esoteric Hi-Fi interconnects have certain capacitance values for whatever reason.  Video cables for monitors are supposed to be I think about 75Ω resistance.  I suppose it's kind of obvious if you look at a decent cable you can see that are usually unbalanced, shielded co-axial cables.

I think my take on this would be, use a decent BNC cable, whack the end of and put a DB-19 or whatever it is that fits on the back of the NeXT and then make a Y cable out of whatever (an old PC floppy cable) to the Soundbox.  Kind of like an homebrew codged together Y cable

He is one step away from this.  Just connect the "extra" wires to the proper pins on a DB19 (or modified DB25) connector and attach to a soundbox.  I plan on trying this out over the thanksgiving holiday, assuming I can scrounge up the proper connectors.

Chef

Any idea what else uses a 19pin connector or where they can be purchased online?

Quote from: "Arti77"Any idea what else uses a 19pin connector or where they can be purchased online?

The Faq referenced earlier had some examples of how to modify a db25 connector for use in place of the DB19.  I have not tried it myself, so I do not know how well it will work.  Here is the link.

http://mail-index.netbsd.org/port-next68k/1998/06/30/0000.html

Chef

Hi all,

I hope to get a soundbox in the next 2 weeks, then I will proceed further with the project (get input devices, connect the Next to a TFT instead of the trinitron monitor, etc.). Results will be provided here ;-)

Of course the used material is not exactly high quality (as I already mentioned before) but it is sufficient for my quick test - I just wanted to know if it works at all. You may even notice that i did not buy a DB19 connector, I just used a DB25 connector where I removed the additional connections with a small saw and rasp. If I find time I may measure the overall signal attenuation of the adapter to check if your assumptions regarding resistance are correct.

I will try to provide screen photographs, although they are usually a bit tricky because of the screen refresh/flickering.

BR,
Günther

Quote from: "w2510a"Hi all,

I hope to get a soundbox in the next 2 weeks, then I will proceed further with the project (get input devices, connect the Next to a TFT instead of the trinitron monitor, etc.). Results will be provided here ;-)

Of course the used material is not exactly high quality (as I already mentioned before) but it is sufficient for my quick test - I just wanted to know if it works at all. You may even notice that i did not buy a DB19 connector, I just used a DB25 connector where I removed the additional connections with a small saw and rasp. If I find time I may measure the overall signal attenuation of the adapter to check if your assumptions regarding resistance are correct.

I will try to provide screen photographs, although they are usually a bit tricky because of the screen refresh/flickering.

BR,
Günther

Thanks w2510a

I was'nt criticising what you'd shown us, on the contrary I'm grateful for your help.  It just struck me that you where not using video cable so I'd have figured the picture might have been poor, but as you say it's fine and as Chef observed the cables properites may well be that fact it works so well.

Again thanks

BTW Blackcube has already shown us where DB-19's can be sourced This Thread (http://www.nextcomputers.org/forums/viewtopic.php?t=89&highlight=unobtainium)

Hello everybody,

I was busy the last few weeks, so it took longer than expected, but finally it is done: I have connected a Soundbox from a Non-ADB Nextstation Color to my Nextstation Mono. The original keyboard plugs into the Soundbox as always, it works perfectly also with the Nextstation Mono.
To connect a VGA/SXGA monitor, I have built an adapter as already posted in the forum some time ago. Everything works fine on CRT monitors like the Olivetti DSM 50-175 and the HP A4033A (from my HP 9000 715/80). On my Dell TFT, the image is too bright (seems like black & white without any grayscale "colors").
You can find some screenshots on Flickr, just search for my account (w2510a) and the keyword "nextstation". I also try to post the links directly below:
http://www.flickr.com/photos/62567718@N00/330084399/
http://www.flickr.com/photos/62567718@N00/330084396/
http://www.flickr.com/photos/62567718@N00/330084394/
http://www.flickr.com/photos/62567718@N00/330084393/
http://www.flickr.com/photos/62567718@N00/330084392/

Have fun!

Great job on this w2510a, and thanks for updating us all on your progress.  I was hoping that this would be possible to do with a custom "Y" cable of sorts.  If you get a chance, can you document how you wired all the connectors, so others can try.  I picked up a couple of db19 connectors from Gateway, but have not had a chance to try anything out yet.

Congrats again on getting it to work.

Chef

Hi Chef & all,

actually the wiring for my connector is quite simple.
I use the monitor cable of the NextStation Mono (DB19 connectors on both ends) to connect the Next with the Soundbox.
On the Next machine, I have made a "dongle" which passes through all wires (DB19 male/female connectors). The following wires need to be connected with the VGA cable (DB15 connectors):
VSync: Next pin 8, connect with VGA pin 14
HSync: Next pin 9, connect with VGA pin 13
Video: Next pin 10, connect with the RGB VGA pins 1,2,3
GND: Next pins 13-19, connect with VGA pins 6,7,8

That's all!

Cheers,
w2510a

Quote from: "w2510a"Hi Chef & all,

actually the wiring for my connector is quite simple.
I use the monitor cable of the NextStation Mono (DB19 connectors on both ends) to connect the Next with the Soundbox.
On the Next machine, I have made a "dongle" which passes through all wires (DB19 male/female connectors). The following wires need to be connected with the VGA cable (DB15 connectors):
VSync: Next pin 8, connect with VGA pin 14
HSync: Next pin 9, connect with VGA pin 13
Video: Next pin 10, connect with the RGB VGA pins 1,2,3
GND: Next pins 13-19, connect with VGA pins 6,7,8

That's all!

Cheers,
w2510a

Very nice work! Thank you for documenting this w2510a. We've wanted to build an adapter like this for some time now and I'm glad to see it works.

I got my db19s from http://www.sfcable.com when I made my own NeXTStation to Mono monitor cable.  If you get on their site and search for DB19, they're $0.50 for the male and $0.60 for the female.  For the cable itself I used a 20 pin ribbon cable and just rolled it up inside of some plastic wire sheathing.

I have a couple of the connectors left though because I bought spares if you want them, NextChef (seeing as how we're both local to the St. Louis area...)  

Although, if the truth be known it would probably be easier just to go over to Gateway Electronics because I did notice that they had a bunch in a bin last time I was there as well...

Quote from: "Ashman"Although, if the truth be known it would probably be easier just to go over to Gateway Electronics because I did notice that they had a bunch in a bin last time I was there as well...

There is not much left a Gateway.  I picked up two of each kind a few weeks ago, and that left one of each in the bin (did not want to take the last ones, just in case someone else really needed them).

On a related note, Do you think there is enough demand/interest in NeXT spec cables to actually get some made?  I need some specialized cables made for a type of machine at work, so am investigating small run custom cable manufacturers.  I would want to get both mono and color Y cables made, and the more I make the less each will cost.  I do not have any pricing info yet, but where would I need to be in order to make it practical for all of us.  Anyone have any experience with this, or a cable fab you have used in the past?

Thoughts?

Chef