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evildragon
September 14th, 2013, 06:10 PM
For some reason my Google is playing dumb and giving me useless results for this.

I have an Teknika MJ-22 monitor and it has these pinouts: http://old.pinouts.ru/Video/teknika_mj-22_pinout.shtml

It's clearly a CGA monitor, but I have an EGA card to use.

Will this work though for the 320x200 16-color EGA games? Clearly I'd think in 350 line mode it'd not work as the sync is wrong, but if I remember the IBM 5153 when in 200 line mode acted the same as a CGA monitor also, thinking the intensity pin would work in this way.

george
September 14th, 2013, 09:35 PM
Most (if not all) EGA cards support CGA monitors. You should adjust the switches on the EGA controller properly. Of course, only text and 200 lines 16 colors graphic modes are displayed properly on all CGA monitors.

commodorejohn
September 14th, 2013, 09:41 PM
As george says, almost certainly yes, as long as you set it to use only 200-line modes.

SpidersWeb
September 14th, 2013, 10:05 PM
I think that could depend on what card your using.

I just tried it with a couple of DIN style displays (that I use as spare CGA) on a 286 portable with EGA. It didn't like it (sync problems) in 80x25.
But that's just one machine. I can say, you wont break it by trying though.

evildragon
September 14th, 2013, 10:24 PM
I think that could depend on what card your using.

I just tried it with a couple of DIN style displays (that I use as spare CGA) on a 286 portable with EGA. It didn't like it (sync problems) in 80x25.
But that's just one machine. I can say, you wont break it by trying though.
I'm going to use this. Technically VGA but it also has a 9-pin CGA/EGA output too.

http://www.uncreativelabs.de/th99/v/A-B/52523.htm

commodorejohn
September 14th, 2013, 11:59 PM
Just set the switches for a CGA monitor and you should be good to go - it should prevent switching to EGA high-res modes.

evildragon
September 15th, 2013, 01:05 AM
Just set the switches for a CGA monitor and you should be good to go - it should prevent switching to EGA high-res modes.

Won't that prevent me from accessing the 16 color 200 line EGA mode though?

modem7
September 15th, 2013, 03:26 AM
Just set the switches for a CGA monitor and you should be good to go - it should prevent switching to EGA high-res modes.
Won't that prevent me from accessing the 16 color 200 line EGA mode though?
Not according to Great Hierophant, who [here (http://www.vintage-computer.com/vcforum/showthread.php?23177)], wrote, "If you run the EGA in color emulation mode for the 5153, you get access to all 16-color modes. Most games used these modes, not the 64-color modes."

Stone
September 15th, 2013, 03:55 AM
I'm going to use this. Technically VGA but it also has a 9-pin CGA/EGA output too.

http://www.uncreativelabs.de/th99/v/A-B/52523.htmThat's a great little card. I've also got one of them and I use it in my XT to drive both an IBM 5151 and a NEC Multisync... at the same time. :-)

vwestlife
September 15th, 2013, 09:26 AM
I had an ATI Small Wonder card which could emulate 720x350 MDA and Hercules modes on a 15 kHz CGA monitor by using interlacing. It actually looked pretty good, if you could stand the flickering. I don't know if they ever made a card which would emulate color 640x350 EGA graphics on a CGA monitor with interlacing.

commodorejohn
September 15th, 2013, 10:26 AM
Won't that prevent me from accessing the 16 color 200 line EGA mode though?
Not on any combo card I've used. It'll still act as an EGA, it just won't switch into high-res modes. I had to use this on an actual EGA monitor with one card because it didn't sync properly, and it still worked perfectly fine with 200-line EGA software.

evildragon
September 15th, 2013, 11:29 AM
Perfect, thanks!

evildragon
September 15th, 2013, 06:42 PM
Ok I think it worked fine. I ran CGA_COMP to test it.

ftp://184.91.249.58/MISC/CGARGB.JPG

nestor
September 15th, 2013, 11:43 PM
I don't know if they ever made a card which would emulate color 640x350 EGA graphics on a CGA monitor with interlacing.
Yes, the ATI VGA Wonder will emulate 640x350 graphics on CGA and TTL monitors.

http://img692.imageshack.us/img692/9342/y7qd.th.jpg (http://imageshack.us/a/img692/9342/y7qd.jpg)


http://imageshack.com/a/img13/2020/4sy1.th.jpg (http://imageshack.com/scaled/large/13/4sy1.jpg)

evildragon
September 16th, 2013, 11:28 AM
Ok I think it worked fine. I ran CGA_COMP to test it.

ftp://184.91.249.58/MISC/CGARGB.JPG

Yes, I know, this is a CGA demo, haha. I actually don't have any EGA programs to test yet so I just ran that to make sure my wiring worked.

Al Hartman
September 16th, 2013, 01:18 PM
I used to have a VGA Wonder that let me display VGA video modes on an EGA monitor. I installed an anti-glare screen to cut down on the flicker. I used it until I bought a VGA monitor.

evildragon
September 16th, 2013, 02:17 PM
I used to have a VGA Wonder that let me display VGA video modes on an EGA monitor. I installed an anti-glare screen to cut down on the flicker. I used it until I bought a VGA monitor.

I wonder how the 256 color modes looked on that. hmmm

Al Hartman
September 16th, 2013, 03:15 PM
It was 20 years ago, so I don't remember.

vwestlife
September 16th, 2013, 03:56 PM
It depends if it was real EGA (digital RGB) or just VGA (analog RGB) through a 9-pin cable.

Many EGA users were using Multisync-type monitors which were upwards-compatible with VGA, so many early VGA cards provided a 9-pin output so that if you had been using a Multisync monitor with EGA, you wouldn't even need to replace the video cable to upgrade to VGA.

For those using fixed-frequency EGA (or even CGA) monitors which could not accomodate VGA's higher sync frequencies and use of analog RGB signals, downscaling/interlacing VGA video to be displayed on those monitors would be possible, but would be far more complex. Since an Amiga can display interlaced 16-color 640x400 video on a CGA monitor, with a little tweaking of the video timing they could probably make interlaced 640x480 video work as well, with a 15 kHz digital RGB video signal that would work on either CGA or EGA monitors. In that case the loss of colors wouldn't matter so much because with plain VGA, 640x480 mode is limited to 16 colors anyway.

evildragon
September 16th, 2013, 04:07 PM
It depends if it was real EGA (digital RGB) or just VGA (analog RGB) through a 9-pin cable.

Many EGA users were using Multisync-type monitors which were upwards-compatible with VGA, so many early VGA cards provided a 9-pin output so that if you had been using a Multisync monitor with EGA, you wouldn't even need to replace the video cable to upgrade to VGA.

For those using fixed-frequency EGA (or even CGA) monitors which could not accomodate VGA's higher sync frequencies and use of analog RGB signals, downscaling/interlacing VGA video to be displayed on those monitors would be possible, but would be far more complex. Since an Amiga can display interlaced 16-color 640x400 video on a CGA monitor, with a little tweaking of the video timing they could probably make interlaced 640x480 video work as well, with a 15 kHz digital RGB video signal that would work on either CGA or EGA monitors. In that case the loss of colors wouldn't matter so much because with plain VGA, 640x480 mode is limited to 16 colors anyway.
Yea in 640x480 it'd be ok.. But I wonder though about 320x200x8-bit, how that would have translated to an EGA monitor with the limited color.

commodorejohn
September 16th, 2013, 06:46 PM
Presumably it would just chop off the low four bits of each color element in the palette (VGA using 18-bit palette entries while EGA uses 6-bit ones,) which would cut the resolution of each by a factor of 16. Basically you'd get similar VGA colors blending into the same EGA color; gradients would become large bands of flat color, etcetera. Here's some quick mock-ups:
http://img547.imageshack.us/img547/6780/t9df.png
http://img842.imageshack.us/img842/537/p07t.png
http://img138.imageshack.us/img138/7821/wmm7.png
http://img571.imageshack.us/img571/3220/sght.png
As you can see, it's fairly acceptable on images that use similar colors only for fine detailing on broadly similar, clearly differentiated areas, but rather disastrous on images that don't adhere to that. (You can just barely make out the dark-grey-and-brown Quake grenade launcher as a large black splot in the bottom center, for example.)

A more advanced controller might apply some kind of gamma correction to reduce this, or at least apply division and rounding instead of ANDing out the low bits altogether, but since this kind of use would be a corner-case anyway, I doubt that was ever done.

evildragon
September 16th, 2013, 07:18 PM
Neat ok, so it's not always good, but it's not always bad though. Ok cool.