Connecting a DOS PC to a PVM

[hosser]

Have you tried the software solution?

Nah, I don't have a supported chipset. I did find a TSR called VGATV but it doesn't work without the XRGB3 in the chain (the signal doesn't sync correctly).

[kamiboy]

Where can I find a list of supported chipsets?

About two years back I had a pile of PC parts that I fished out of a e-waste container at my previous job. Alas I think I ended up picking one or two things to keep, and threw away the rest, a bunch of different vintage graphics cards included.

If I knew about this tool then I stood a chance to find one a supported chipset.

[ZellSF]

Is 640i not an option? Because trying to fit a 640x400 image into 320x240 isn't going to end up pretty.

[kamiboy]

Mode 13h is natively 320x200, so I think it should look fine.

[hosser]

Is 640i not an option? Because trying to fit a 640x400 image into 320x240 isn't going to end up pretty.

But if the XRGB is set to 320x240, why would it be a 640x400 image? Forgive me if I'm missing something.

Mode 13h is natively 320x200, so I think it should look fine.

Yeah, I'm confused as to why it looks all squished. It should be perfect. :/

[Fudoh]

But if the XRGB is set to 320x240, why would it be a 640x400 image? Forgive me if I'm missing something.

DOS text mode (your photo with the red box with text) is originally 640x400 - that's why it looks so bad down converted.

Mode 13h is natively 320x200, so I think it should look fine.
Yeah, I'm confused as to why it looks all squished. It should be perfect. :/

you're putting a 320x200p signal onto a 320x240p signal. Now the extra 40 lines have to go somewhere, don't they ?

[hosser]

But if the XRGB is set to 320x240, why would it be a 640x400 image? Forgive me if I'm missing something.

DOS text mode (your photo with the red box with text) is originally 640x400 - that's why it looks so bad down converted.

Mode 13h is natively 320x200, so I think it should look fine.
Yeah, I'm confused as to why it looks all squished. It should be perfect. :/

you're putting a 320x200p signal onto a 320x240p signal. Now the extra 40 lines have to go somewhere, don't they ?

Ahh, I see. That makes sense. So would I be better off setting a higher resolution on the XRGB? I'm guessing nothing will be perfect, but maybe there is an option that looks better than 240p? I'm not sure what resolutions the PVM 2053MD supports. I think I remember reading something about 600 lines?

[ZellSF]

To explain (admittedly not an expert, so entirely wrong person to explain): while 320x200 is the resolution DOS games run at, it's double scanned by the hardware. The output is 640x400.

The XRGB is trying to fit 640x400 into 320x240 and I'm guessing it wasn't designed with PC use in mind: it's going to turn out pretty bad.

Just making the XRGB output 480i (with 1x scaling) makes the most sense to me. Well getting a PC that can output 15khz or a monitor that accepts 31khz both obviously makes more sense.

[hosser]

To explain (admittedly not an expert, so entirely wrong person to explain): while 320x200 is the resolution DOS games run at, it's double scanned by the hardware. The output is 640x400.

The XRGB is trying to fit 640x400 into 320x240 and I'm guessing it wasn't designed with PC use in mind: it's going to turn out pretty bad.

Just making the XRGB output 480i (with 1x scaling) makes the most sense to me. Well getting a PC that can output 15khz or a monitor that accepts 31khz both obviously makes more sense.

Thanks. I've learned a ton from people on this forum.

I'll try 480i tonight. I have thought about getting a 15KHz graphics card like the ArcadeVGA but I wanted to try everything possible with the hardware I currently have before spending more money. I have a modern LCD and an HDTV that will accept 31KHz but the PVM is the only CRT in my setup and I really want to play my DOS games on a CRT display rather than an LCD - adding a second CRT to my setup is not an option due to space!

[kamiboy]

I suppose the best way to play a mode 13h game on a 15khz CRT would be via a TSR that rasterizes the 320x200 source inside a 240p window without scaling leaving a 20 pixel gap at the top and bottom.

Then one can manually correct the aspect ratio by stretching the V-size of the display using a service menu.

A bit of a hassle, but should result in a pretty good picture quality, in theory.

[kamiboy]

I dragged out the old box 'o PC parts and decided to give this 15khz TSR thing a go, alas no dice.

I have a handful of graphics cards here. None were supported by MON-ARC. But a few were seemingly supported by VGATV.

After wasting a day messing around with the setup I finally managed to get one of my cards to throw up a stable image on the old B&O CRT. Unfortunately though, this only worked for text mode in the command prompt. As soon as I launched a game the whole thing shat the bed.

I am writing up VGATV as a lost cause, but I want to give MON-ARC a go. I just have to hunt down one of the handful of cards that it supports. A search on eBay did not surprise me a bit. Lots of cards for sale, all asking too much. I guess they know only crazy people would be looking for vintage PC hardware.

[hosser]

I dragged out the old box 'o PC parts and decided to give this 15khz TSR thing a go, alas no dice.

I have a handful of graphics cards here. None were supported by MON-ARC. But a few were seemingly supported by VGATV.

After wasting a day messing around with the setup I finally managed to get one of my cards to throw up a stable image on the old B&O CRT. Unfortunately though, this only worked for text mode in the command prompt. As soon as I launched a game the whole thing shat the bed.

I am writing up VGATV as a lost cause, but I want to give MON-ARC a go. I just have to hunt down one of the handful of cards that it supports. A search on eBay did not surprise me a bit. Lots of cards for sale, all asking too much. I guess they know only crazy people would be looking for vintage PC hardware.

Yeah I haven't found anything that works with Mon-Arc either. Like you I did have some success with VGATV but the text didn't look any better than running it through the XRGB-3. Gave up in the end and am just using my Dell U2412M for my DOS PC via bog standard VGA.

[kamiboy]

Seeing DOD prompt running in 15khz has motivated me to press on and find something that works with ARC-MON. It looked really good compared to what you see on a PC monitor. I can only imagine that mode 13h games are going to look fantastic in 15khz instead of the ugly blocky line doubled mess that they are rendered as.

Then I just meed to figure out a joypad solution and I am set.

For now I've come up with this strange harness for my "PC" because I think traditional towers take up too much space and are ugly to look at.

[kamiboy]

Well colour me purple and call Barney. I actually finally managed to get a usable image on the screen that carried through to games as well.

Firstly, I really wanted to try MON-ARC, so I went ahead and purchased the cheapest compatible card for it, a Matrox G400. To my disappointment that route proved to be a waste of money, time and effort. All it got me was a garbled image on my B&O TV.

So I thought, either the fault was with my TV, or with that sync combiner cable that I had built myself. Because the G400 was supposed to work.

To take both out of the equation I decided to test the PC setup on my BVM A. I first tried with my sync combiner cable, but no dice. Next I busted out the classic VGA to BNC cable, and used the crude T-adapter H&V sync combining. This, once again gave me nothing usable on screen with the G400, so advice against acquiring that card for MON-ARC.

As a last resort I decided to test that S3 Virge card that I had. That card does not work with MON-ARC, but was the only card that gave me a stable picture in the text prompt via VGATV.

This time lady luck lifted the old skirt for me. I got a stable image, and not only in the text prompt, I managed to launch DOOM, Wolfenstein 3D and Monkey Island 2 in 15khz, all working, and looking amazing, scanlines and all.

One thing to note, VGATV would only work if I used the /ISP option to invert sync polarity. Perhaps this is necessary due to the crude T-adapter sync combining that I had resorted to. Now, I wonder why my sync combiner cable was a dud.

I also spent some time getting a USB gamepad to work in DOS. Wasn't easy, but worth the trouble as now I can play PC games in a console-like manner, on a 15khz TV with scanlines.

Huzzah!

Next challenge will be to miniaturize this hideous setup so it will be more palatable to my sensitive aesthetic senses.

[hosser]

Well colour me purple and call Barney. I actually finally managed to get a usable image on the screen that carried through to games as well.

Firstly, I really wanted to try MON-ARC, so I went ahead and purchased the cheapest compatible card for it, a Matrox G400. To my disappointment that route proved to be a waste of money, time and effort. All it got me was a garbled image on my B&O TV.

So I thought, either the fault was with my TV, or with that sync combiner cable that I had built myself. Because the G400 was supposed to work.

To take both out of the equation I decided to test the PC setup on my BVM A. I first tried with my sync combiner cable, but no dice. Next I busted out the classic VGA to BNC cable, and used the crude T-adapter H&V sync combining. This, once again gave me nothing usable on screen with the G400, so advice against acquiring that card for MON-ARC.

As a last resort I decided to test that S3 Virge card that I had. That card does not work with MON-ARC, but was the only card that gave me a stable picture in the text prompt via VGATV.

This time lady luck lifted the old skirt for me. I got a stable image, and not only in the text prompt, I managed to launch DOOM, Wolfenstein 3D and Monkey Island 2 in 15khz, all working, and looking amazing, scanlines and all.

One thing to note, VGATV would only work if I used the /ISP option to invert sync polarity. Perhaps this is necessary due to the crude T-adapter sync combining that I had resorted to. Now, I wonder why my sync combiner cable was a dud.

I also spent some time getting a USB gamepad to work in DOS. Wasn't easy, but worth the trouble as now I can play PC games in a console-like manner, on a 15khz TV with scanlines.

Huzzah!

Next challenge will be to miniaturize this hideous setup so it will be more palatable to my sensitive aesthetic senses.

Damn, nice work. I might have to try that /ISP option on my setup!

[schadenfreude]

Yo dudes, I've been going down this same route to connect my DOS machine to my PVM, but I'm having less luck than kamiboy. I'm using the same setup as kamiboy with the T-connector for composite sync on the VGA to BNC cables.

First I tried arcmon. Upon rebooting the system, the DOS prompt displays in beautiful 200p on the PVM, but upon launching any game, the screen goes black.

Then I tried VGATV and also got a 200p DOS prompt (I also needed to set /ISP), but game compatibility is all over the place. When I booted Monkey Island, the first screen was stunning, but then as I approached the SCUMM Bar, I saw a few pixels here and there had the wrong color. I tested entering and leaving the bar several times; sometimes the image was perfect, but most of the time there were some sections of the screen that had incorrect colors.

I then tested Wolfenstein 3D, and again, rarely the image is perfect, but most of the time there is awful washing out of colors across the screen. Every time the screen flashes — like when I am shot or pick up an item — the colors reset, and if I'm lucky, the correct image comes out. Now there's a way to play the game! Doom gave a similar story, but the colors were way worse (think inverting the RGB colors in an image), and the game was running really slowly too. I tried other VGATV parameters, but the changes would either give me a black screen or the same subpar results. Note that my machine is running an S3 Trio64v+, and VGATV claims that it supports S3 chipsets. I don't feel like buying other cards just for testing though.

Finally, I have the Extron Emotia as the old standard, but it isn't perfect. It's not just that the machine averages lines starting on the second line: in Monkey Island, for example, if I move the plus-sign cursor down on the screen, the single-scanline horizontal part of the cross will be one scanline, then one scanline, then one scanline with ghosting above it, then split into two ghosted scanlines, then one scanline with ghosting below it, and then the pattern repeats. Thus I figure even if I were to shift the signal lower before giving it to the Emotia, I'd get the same problem on different lines. I chalk this up to the 400p/70Hz mess that the Emotia has to deal with, though I noticed the guide stuck on the bottom of the Emotia mentions supporting this mode. Maybe Extron figured that the machine's handling of it was good enough.

I think my best bet at this point is to use DOSBox with the Emotia or Soft15kHz. This guy got some excellent results with this setup: http://imgur.com/r/crtgaming/8Q1vf.

[Fudoh]

I think my best bet at this point is to use DOSBox with the Emotia or Soft15kHz.

You definitely need to prescale the graphics. With the Emotia on its own, it will try to convert 400 lines to 240p lines which gives you the scaling/ghosting problems you're seeing. You need something to output 480p with 400 active lines in the middle. This will result in a perfect output from the Emotia. After that you need to adjust your monitors vertical size so hide the bars. I guess DOSBOX has the options to do this.

[schadenfreude]

Will the Emotia give the ghosting behavior for any signal that doesn't have 480 lines of vertical resolution? That is, if it produces ghosting on a 400-line image, would it also produce ghosting if given an 800x600 resolution image, for example?

[Fudoh]

pretty much, yes.

[kamiboy]

Well, as per my last post here I did actually manage to get things working. Alas I have not touched it since as I mostly just did it for fun, and blue is the moon on a night that my whims skew DOSwards.

In any regard, I feel that perhaps the graphics cards are not so much to blame here as we are feeding TV's a signal way out of spec. We should properly bring down the levels of the RGB signal from PC to TV level, and combine sync using a sync combining circuit.

[schadenfreude]

In any regard, I feel that perhaps the graphics cards are not so much to blame here as we are feeding TV's a signal way out of spec.

But both of us tested the same games on the same displays — you using a BVM, a PVM for me, but same shit different day — and my results were far worse than yours. I have to assume the video card is at fault, yes?

[kamiboy]

Not necessarily. As I said, PC's put out an RGB signal with a higher voltage than TV's are expecting. And using a T-connector to combine sync is not right either. To pin graphics cards as the culprit we need to first rule out every other factor.

Also, SONY monitors are not very flexible when it comes to video signal acceptance.

I did end up playing through DOOM without issues on my BVM using the setup I mentioned last, so it can work on such a setup.

[schadenfreude]

I get that we're not giving our TVs a signal that it expects, but what I find odd is that we both used the same setup and got wildly different results — hence why I assume the video card is at fault.

[kamiboy]

A PVM and BVM are not the same. The internals are completely different. Plus, you don't use the exact same graphics card as me, right? The chipset might be the same, but PC's are complex beasts, there are too many factors.

[schadenfreude]

Yep, more reasons why I think using DOSBox with an Emotia or Soft15kHz is the better solution, though I hate owning but not using the real hardware.

[kamiboy]

While I am glad I made the setup work I could easily have gone without. I was stuck with an IBM compatible PC for most of my youth as a gaming machine, but in hindsight I am not too fond of the platform or the games.

If I want to go back and play something it will be one of a tiny handful of games I would consider worth going back too. Ironically, now that I have gotten into Japanese PC's almost any of those games I might go back to are available as an option on one of the many Japanese systems that I have acquired.

The PC-98 has DOOM I&II, and even Wolfenstein 3D. The X68000 has Lemmings, FM Towns has a bunch of classic adventure games, like the two first Monkey Island games.

Ironically though, I did recently discover that there is a enhanced port of the PC-88 game Zeliard available for DOS. So I am going to be needing that IBM compatible PC for at least one game, a Japanese one, all while I'll be using Japanese hardware to play the handful of western developed games that I might ever want to play.

[schadenfreude]

I grew up with PCs as well, and while I no longer have any interest in the side-scrollers I played (see all those Epic and Apogee releases), the FPSes, RTSes, RPGs, and adventure games are still endearing to me. Often the DOS version is the best one, and if not, my nostalgia might convince me to choose it anyway.

As on update on my project, I've turned to using DOSBox with Soft15kHz on an old laptop piped to the PVM. The results are stunning, and I can't imagine going back to looking at line-doubled 200p graphics. It even looks better than using the Emotia (even with the image-shift trick), which seems to soften the image a bit and add a little bit of flickering. They're both good, but Soft15kHz has the edge.

[NJRoadfan]

How well do these solutions work with the commonly used Mode X (320x240)?

[kamiboy]

I don't remember that mode being commonly used. It is a VESA mode if memory serves me well, and not part of the standard modes. Which games used it?

[Elbaid]

Hoffer, can't you get a cheap Radeon card and install CRT-Emu drivers? You'll be able to run your DOS games with DOSbox through the PVM nicely and have loads of control over the image this way. That's how I do it and the games look fantastic