Scandoubler for 520ST for VGA screen use?

[blakespot]

There are external scandoubler boxes available for the Amiga that let them work with standard 31kHz VGA displays. Do such devices exist for older ST's?

 

Where can I find one? Tnx.

 

 

 

blakespot

[+Guitarman]

I built an adapter that will allow you to use a VGA monitor in HiRes mode on any Atari ST using the 13pin monitor port. If you like, I can post the directions and schematic for it when I get home. I am using a 19" Dell monitor with all my ST/TT/Falcon systems and the picture is amazing. The adapter will not work for low/medium res.

Edited February 14, 2007 by Guitarman

[+remowilliams]

There are external scandoubler boxes available for the Amiga that let them work with standard 31kHz VGA displays. Do such devices exist for older ST's?

I've never seen one for the STs. I've got an external scan doubler/flicker fixer for the Amigas, one of these days I plan on trying to put a custom cable together and connect it to the STs. In theory it should work.

[blakespot]

There are external scandoubler boxes available for the Amiga that let them work with standard 31kHz VGA displays. Do such devices exist for older ST's?

I've never seen one for the STs. I've got an external scan doubler/flicker fixer for the Amigas, one of these days I plan on trying to put a custom cable together and connect it to the STs. In theory it should work.

Yes, all that is needed to get an ST working on an "Amiga monitor" is a cable providing the flag voltage. That said, an Amiga scandoubler should work fine as long as a custom cable is built with - what is it, 12v on one pin? The only way I've got room in my computer room for an ST setup is to let my KVM'ed 19" Sony do double-duty as an ST display.

[FastRobPlus]

Yeah, should be a matter of just getting the pin outs right. Redmond Cable could likely make an Atari ST to Amiga converter cable and then you could obtain an Amiga external flicker-fixer.

 

I go through a Video Key into a scan doubler that taked composite input. That gets the job done but of course you are getting the fuzziness of composite. And the video key device itself for the Atari has become a rare item.

[+poobah]

I've looked into making one, need 3 channels of A/Ds, a PLL, some dual port memory and a DAC. Parts are kinda pricey tho =[

 

Got links to the Amiga ones? Making an adapter cable should be simple enough.

Edited February 14, 2007 by poobah

[ijor]

I've got an external scan doubler/flicker fixer for the Amigas, one of these days I plan on trying to put a custom cable together and connect it to the STs. In theory it should work.

 

Somebody tested an Amiga scan doubler. According to him, it doesn't work with fullscreen.

 

OTOH, the same person tested a newer LCDTV with built-in scan doubler using a SCART (RGB) connector. It works like a charm.

[FastRobPlus]

I've looked into making one, need 3 channels of A/Ds, a PLL, some dual port memory and a DAC. Parts are kinda pricey tho =[

 

Got links to the Amiga ones? Making an adapter cable should be simple enough.

 

I thought Softhut.com had them but I see now that they have been out of stock since Mid '06...

[+remowilliams]

I thought Softhut.com had them but I see now that they have been out of stock since Mid '06...

Yeah they did have them, that's where I got mine.

[blakespot]

Somebody tested an Amiga scan doubler. According to him, it doesn't work with fullscreen.

What does this mean? If border color tricks are in use? As I understood it, the Atari ST does not have actual overscan.

 

 

 

blakespot

[ijor]

What does this mean? If border color tricks are in use? As I understood it, the Atari ST does not have actual overscan.

 

It does have overscan. Not in a documented official way, but it has.

 

Overscan/fullscreen is used in a few commertial games, and also in most demos.

 

Search the ST forum for overscan, fullscreen and you should find plenty of references.

[danwinslow]

You can buy 'upscan converters' that will do what you need.

 

Google for XRGB or iScanVP20/30.

[+remowilliams]

You can buy 'upscan converters' that will do what you need.

 

Google for XRGB or iScanVP20/30.

Those things suck. What the OP (I'm quite sure) is looking for is an RGB -> RGB device like a scan doubler.

 

Those 'scan converters' take composite/s-video and convert it for VGA display. They're cheap and readily available. The 'Cheese Box' is a good example.

[tjlazer]

Don't tell me you are not going to put a nice SC1224 monitor on that MicroMate 520 STation!!! You really want to get shot? LOL Get a JVC SC1224 monitor!

[blakespot]

Don't tell me you are not going to put a nice SC1224 monitor on that MicroMate 520 STation!!! You really want to get shot? LOL Get a JVC SC1224 monitor!

I want a SC1224, sure. And I'll probably end up with one as part of the bundle I end up with - but there's simply zero room in my computer area for this setup UNLESS I can put the STation under an existing CRT - and the only CRT on the desk without a computer under it is my currently-3-way-KVMed 19" Sony.

 

See: http://www.bytecellar.com/qtvr.html

 

Wish I had a shade more room.

 

 

 

 

blakespot

[blakespot]

It looks like this might do it:

 

http://gear.ign.com/articles/358/358098p1.html

 

It accepts "21-pin Japanese RGB" in. Seems a cable could be built to convert the ST's RGB out to that in, and then it's VGA out. Anyone done this before, I wonder?

 

 

 

 

blakespot

[ppera]

Practically every VGA monitor, including new TFT ones can display Atari ST's monochrome output.

What some call adapter is actually following:

Connect mono out to all 3 RGB inputs of VGA, H and V sync to same and GND to GND, plus connect monochrome sensor to GND and it is all. Desktop will be not nice on TFT because of moare, better is on CRT monitors.

 

Instead scan-doubler TV card may be good and cheap solution. With S-video out even pretty good pic-quality.

I posted here thread with link how to make S-video from ordinary ST(e).

Not to mention possibility of recording great actions!

[techie_alison]

I wonder if we ought to take a new direction on this overall topic. And field test the LCD Scart televisions that also accept VGA input. Post our experiences with different models.

 

I've looked into scan doubling professionally and to get perfect results is expensive, as in having to completely reprocess the signals and scan lines. The cheap options, well, they're crap. I have a scan doubler here which I use for testing of old computers on a VGA monitor. It's ok, but it's about as good as UHF going through the aerial on a TV.

 

A good scan doubler can be expected to cost about £100 in UK money, while a standard Samsung 17" LCD television with additional VGA in, is only £150.

 

My next *project* is to buy one of these Samsung TV's to see how good they are, and look at building a switch box with SCART and VGA out on it. So rather than trying to come up with a wonderful scan doubler solution, just making a low cost switch box to work with the LCD televisions that are appearing out there.

 

Does anyone have experiences of these new LCD tvs that also accept VGA in. The Scart input is fine as I use a 26" LCD with my ST here, but it doesn't take VGA in so I have no reference point of how they lock to the ST's high 31.5. Some VGA monitors just won't do it and report signal as out of range.

 

The absolute best LCD monitors for ST's high res I've found to be the NEC LCD's. They scale the resolution ever so well. The Hanns-G LCDs though are really flakey.

[+poobah]

I haven't found an LCD that'll do 15 KHz yet.

 

As for the scan doubler, I figured it would look decent if I way oversampled the incoming signal. The ST's sync signals should be fairly solid (I haven't checked tho). If you took several samples per pixel, I think it would minimize shimmering and what not.

 

Since we'd only be buffering one (or two) ST lines, the memory price shouldn't be horrible. Granted, you aren't going to do it for $30 tho.

[techie_alison]

An LCD television will do 15Khz. Straight RGB through the scart cable. I do it right now on a 26" Panasonic, but it doesn't have a PC VGA input like some of the newer ones do.

 

Oh hang on... You're in the States aren't you. I don't think you have scart euroconnectors over there. Not sure what your NTSC direct connection RGB equivalent is??

Edited February 15, 2007 by techie_alison

[Christos]

Alison, though I am sure you already know that, they don't have SCART in North America. It has to be S-Video. However I do remember reading an article or a post about this and it was said it worked fine in both modes. Unfortunately I can't find it right now.

[+remowilliams]

I haven't found an LCD that'll do 15 KHz yet.

I luckily have found *one* out of the bunch I've had or gone through. Funny thing is it's one of those off brands I found on deep discount at Compusa a while back.

 

Oh hang on... You're in the States aren't you. I don't think you have scart euroconnectors over there. Not sure what your NTSC direct connection RGB equivalent is??

Bingo. We don't have an NTSC direct RGB connection.

 

I do actually have a SCART RGB -> VGA device here somewhere. Theoretically if I provide that powered 'switch signal' to the SCART jack, and the STs RGB output I *think* I should be able to get that to work.

[ppera]

If LCD monitor has TV tuner it usually has composite and S-video inputs.

Quality should be much better than with any available scan-doubler.

However, I didn't see anything under 300 Euros.

Except some Gaba monitors without tuner, but with composite video input. But it is far from good brand.

I think that in US they have chinch connectors for composite video.

[blakespot]

If LCD monitor has TV tuner it usually has composite and S-video inputs.

Quality should be much better than with any available scan-doubler.

However, I didn't see anything under 300 Euros.

Except some Gaba monitors without tuner, but with composite video input. But it is far from good brand.

I think that in US they have chinch connectors for composite video.

Why do people keep talking like scan-doublers lower quality? I've got an internal scan-doubler on my Amiga 1200 tower and it just...doubles the image. 320x200 screens are 640x400 with 2x2 pixel "pixels," effectively. No noise or interference or whatever. Blocky, sure, but what do you expect?

 

 

 

blakespot

[tjlazer]

Don't tell me you are not going to put a nice SC1224 monitor on that MicroMate 520 STation!!! You really want to get shot? LOL Get a JVC SC1224 monitor!

I want a SC1224, sure. And I'll probably end up with one as part of the bundle I end up with - but there's simply zero room in my computer area for this setup UNLESS I can put the STation under an existing CRT - and the only CRT on the desk without a computer under it is my currently-3-way-KVMed 19" Sony.

 

See: http://www.bytecellar.com/qtvr.html

 

Wish I had a shade more room.

 

blakespot

 

Ah I see yes I can relate! I have too much vintage crap in my house too. Not enough room for it all! But you really do need to get an Atari monitor, it would look great on that Micromate!