Old Fixed-Sync Monitors under Linux? 16
Hautis asks: "I read somewhere that it should be possible to use huge, old
fixed-sync monitors with any (*vga) video card under Linux,
once you tell XFree86 the exact sync ranges or whatever values
it needs. I happen to have a couple of old VAXen, that is, VAXstations, lying around in my family's cellar. 19 inch mono and RGB tubes, fixed sync. What kind of cables would I need (I can solder well enough)? Would I be able to use text modes also, would a frame buffer beneeded for this? What about (S)VGAlib? Can I have two graphics
adapters, one conn't to my crappy old 15-inch and one to the
huge ancient particle accelerator? Or should I switch between the displays when I want to use X? Will I get a cancer for staying up nights surrounded by 80's display technology?"
Yes, you can do almost everything you want (Score:3)
http://www.devo.com/video/
I used an old DEC monitor for a couple of
years a while back. It worked fine. You basically
have two options
1. Buy a video card specially made for fixed
frequency monitors
2. Fiddle with your X config so that it runs
at the frequency the monitor wants.
Option #2 is nice because it's free and works
well, though ordinary text modes don't work.
The main problem you're likely to have is that
many fixed frequency monitors have 3 BNC connectors and expect sync signals mixed in with green. You can build a simple circuit to deal
with this. Fiddling with X timings is tiring but
eventually you get there.
Matthias
SVGATextMode (Score:2)
Don't know about cancer but if you need to be able to use the monitors with textmode SVGATextMode can help you. It lets you set the scan rates while running text mode. And gives you much better text mode too.
As for cables... Many old monitors used RGB cables. Here is the pinouts for your standard SVGA connector:
You probably want to connect the red, green and blue cables to the red video, green video and blue video. The inside pin will be the video. The outside "shield" is the ground. Connect the ground to the analog grounds. The monitor ID pins are unused. The sync pins shouldn't be needed for a fixed frequency monitor.
If this works good! Otherwise don't sue me, I've never tried this before.
As for cancer. Just don't smoke.
Re:My little addition (Score:1)
Yes, but they tend to have really really poor video cards. We have a SS20 here, with a very good monitor on it, but the video card can only take 8bpp... it would be a pity to waste the 19" GDM1962B on such a card :-)
Been there, done that. (Score:2)
My home page has some info. (Score:1)
My home at:
http://freeweb.pdq.net/jcooper [pdq.net]
Has a bit of a howto on the subject. It also includes documentation that I recieved from a video card hacker on how to squeeze normal text modes out of some monitor/card combinations. It's a scary, very cool hardware hack that I haven't delved into yet. It involves flashing your video card a modified BIOS.
Last night I just setup the fb console device in the 2.2 kernels to allow all of my virtual consoles to display. I'll be documenting that as well, sometime in the future. A legible 154x98 text mode is a rather amusing sight to behold.
It's not all that difficult (X was working within 30 minutes for me) and it's well worth it, as these old workstation monitors were made like tanks.
My findings (Score:2)
Fixed sync isn't a problem, all you have to do is find a good modeline (and for text mode, use fb or svgatextmode). But, most of these monitors are nastier - composite sync or sync-on-green. Then you'll have to find a video board that supports these sync modes, or build an adaptor. These are the links I found:
One of these pages claims that the MACH64 can work with my monitor, but I have a VLB one and it doesn't (the modelines given in the page give me "illegal mode according to MACH BIOS" or something). I'll try to exchange it for a PCI. Otherwise, if anyone can send me more modes I'll be very grateful :-)
No, your not genna get cancer (Score:1)
I did not have much trouble configuring XFree86 3.3.x, but XFree86 3.9.x was hell, it took me several hours to get it to work, because I had to write a modeline (not something i normaly do). The best thing I can say, start on a weekend!
Now that I'm typing this, I'm wondering if that same friend that got me the monitor is ever genna get me a vaxstation or a decstation, like he said he would. Anyway, good luck.
Matrox/Sync on Green/Fixed Freq on Linux. (Score:2)
Good Luck...
-Rich
HP Fixed Frequency Monitors & Linux (Score:1)
There are two tricks to this: the first is to get a video card that supports Sync on Green - I'm using a Matrox card. The second is to find the correct modeline.
I tried it under Accelerated X, (4.1 and 5.0) but it failed miserably. Under XFree86, however I was able to (after 2 hours) get a set of Modelines that work. So now I'm running X in 1280x1024x32bit with a Matrox G200 card.
I'd assume this would work under any XFree 86 supported platform, but YMMV.
Email me at ken@spam.networkoverlord.com [mailto] (remove spam) if you want futher info, or my XFree86 config.
Sun 1962B (Score:1)
The major problem seems to be getting a c-sync from the h-sync + v-sync. I did this in the past by using this simple circuit:
H--+--|<|--+
...|.......|
...+--Pot--+
...........+--Csync
...+--Pot--+
...|.......|
V--+--|<|--+
Ignore the dots, I had to put them in for formatting reasons (no < code>? Grrr
The pots were 100Ohm - 1kOhm (set at about 500Ohm), and worked fine with Matrox Millenia, and Cirrus Logic based cards, but not with S3 based cards. The diodes are small signal diodes, and may need to be reversed depending on the monitor.
I think you really need an OR gate (take +5v from the mouse/kbd ports) to do the job properly.
You need to spend a while fiddling with xvidtune, sync timings and sync lengths, together with sync polarity. An alternative to xvidtune is Matrox's NT (and '95, I think) driver, which includes a similar utility + 100s of monitor defs to try. It is relatively easy to convert the Matrox timings to XFree86 modelines.
Matroxs seemed to work if you just wired up the H+V sync directly to the C sync, but the range of acceptable timings was reduced quite a bit. You have to trade off time farting around with hardware vs. time farting around with software
When I was a poor student, and 19" monitors cost megabucks this was a great hack, not so great these days, but probably still worthwhile if you've got the time...
Re:My findings (Score:1)
What a coincidence. I just set this up yesterday. I use the following modeline with an S3Trio64 attached to a Sun 1962B monitor. I am using a cable that was hacked together by someone else so I have no idea how it is connected.
It looks awfull due to a lot of ghositng/aliasing. I will check out those links you posted to see if I can get a better modeline. As far as I know if you want 1152x870 you need a 100Mhz dot clock.To get that modeline I first used some numbers pulled from some nontechnical sites most of which were wrong. By pure luck I eventually came up with something that synced just enough so that I could almost run 'xvidtune' on. Then it was just trial and error. (mostly error)
Sun-3 19" Color Hitache Fixed Frequency (Score:1)
I haven't seen anyone post on the monitor mentioned in the subject, which happens to be the one that I own, so I'll add in my 2cents.
To avoid the problem of finding a sync-on-green video card with decent X drivers, you can remove the plastic casing of the monitor and unscrew the back metal plate. You will find a switch there that toggles the monitor between sync-on-green and v/h sync. Move it to v/h sync. Now you can either make a VGA to 5 BNC cable, or just buy one. They are about 50$ new, but you can usually find these things attached to junk that no one wants either in your company's basement or at a show. If you have to make one, someone here has already posted the specs.
You might want to attach the monitor to your PC at this point without putting it back together. I had to adjust the plastic dial on top of the flyback (the thing that attached to the suction-cup going into the tube) in order to achieve decent brightness at 1152x900, but don't adjust it too much.
Make sure you have some kind of console into your PC, because text mode will not work and you'll just see gibberish. Add a modeline entry in the XF86Config file for this monitor. The one I use is:
Modeline "1152x900" 92 1152 1216 1360 1456 900 901 909 945 -hsync -vsync
Now start up X, and you should be good to go. The monitor is file, although it does use up a lot of electricity and focus is inevitably bad. Still, it's much nicer than a 14" of 15" monitor.
My little addition (Score:2)
Google was great for giving me the information I needed. One big problem is that there is no one page that tells you everything or has links to everything.
So here's some stuff:
Special video cards (good ones, recent acceleration technology) are available. They're more expensive than regular cards, but you're pretty much guaranteed that they'll work. They are specially designed to display text modes on those monitors, which is a huge plus.
Here's a link:
http://www.si87.com/ [si87.com]
There are more companies. A search will find them quickly. I remember seeing one that used S3 chipsets. A good thing because they're very supported. Many of these companies explicitly state Linux support. That's another good thing.
If you want to use a regular video card, be mindful of the specs on your monitor. I found an exellent source of monitor data here [griffintechnology.com]. There are DEC fixed frequency monitors in there, among many, many more.
If you have sync-on-green, you probably have 3 BNC connectors on the back of your monitor. Any Matrox card will drive this. There's a "sync-on-green" option in the XF86Config file for that. VGA-to-BNC cables can be bought fairly cheaply.
If you have composite sync, you probably have either four BNC connectors or a 13W3 connector (3 large coax pins and 10 regular pins). Don't bother looking for a bare connector to make a cable with. It's a very special kind of cable due to the mixture of coax and regular multiconductor cable. If you want to hack an existing cable (or just buy one to go straight) IBM sells them for US$27.00 compared to everyone else (including Sun) that sells them for ~US$80.00.
ATI cards support composite sync. It's an option in the XF86Config file.
To do composite sync on any other card, you can build a little logic circuit, but I *really* don't recommend that because 13W3 cables are relatively hard to hack, plus you'll get a lot of signal loss. For the price of a card you don't have to screw with, it's worth it.
Having looked at these options, I looked at what came with the monitor: a very old pizzabox Sun 3/80. I only wanted an Xterminal anyway and there is some software called XKernel that turns an old Sun into one. Get it here [columbia.edu].
This is the option I'm going with. No major screwing around, plus I get what I want. I bought a cheap ethernet transceiver from D-Link (I had to slice off some of the plastic on the back of my Sun to get it to fit), and I am now waiting for my 13W3 cable to come in from IBM Canada (It *is* a special order, after all).
These old Sun's are easy to find, and tend to have very nice monitors on them. I saw a couple of old Sparcs here for sale for ~CAN$50 each. You can't beat that. They had monitor cables too.
So that's my little experience. It's not exactly tuned to the question, but I'm sure there are many others (I *KNOW* there are) that are watching this question with interest.
Re:My findings ADDITIONAL (Score:1)
I fixed the ghosting with a better video cable. It looks great now!
I found timing parameters for the SUN GX and TGX in the Sun framebuffer FAQ found on sunhelp.org [sunhelp.org]. There are actual modelines for the TGX in the FAQ. Unfortunately I can't test any of them as my video card dosen't have a fast enough dot clock. Despite what a lot of web pages say (many are wrong) the GDM-1962B has fixed horizontal refresh or line rates of 61.9KHz and 71.7KHz. I don't believe it actually supports 1024x768 at all. My modeline uses a 60.3KHz line refresh for a resolution of 1024x768. This shouldn't be supported. The monitor is old and I have played around with some of the internal adjustments, so I suspect that it is running outside of its factory specs. :-)
If you are having trouble with image position or pincusion take the GDM-1962's cover off. I found a bunch of fairly well labled adjustment screws.