Amiga 3000 and Dell flat panel LCD?

[Nagromme]

I'm looking at buying a Dell 1905FP for my Mac and PC to share--and since it has analog VGA input, I'd REALLY like to get it working on my Amiga 3000 too!

The A3000 signal, IIRC, is non-interlaced 60 Hz horiz., 31 Khz vert. The Dell seems to JUST cover that range!

But of course the Amiga's sending non-standard resolutions, like 640x400. What will happen? Can I use this LCD on my Amiga? If so, would the image be squashed? Floating in black borders?

I know I won't get the Dell's 1280x1024... I just want my Amiga running with SOME kind of display sharper than TV so I can play 2-player Lemmings (NTSC) and access my Final Writer and DeluxePaint files. And I don't want to fry anything

(LCD specs: http://support.dell.com/support/edocs/monitors/r83546/EN/about.htm#Specifications )

If not this, would any LCD be usable on my Amiga?

(I won't even hope for using interlaced modes--so no OpalVision. But my Amiga 520 adapter has been filed down to send OpalVision to TV in a pinch.)

Thanks for any advice! I look forward to getting back into my trust Amiga...

[glitch]

Hi,

     I'm sure the monitor will work, but either the 640x400 screen modes will end up using only the center of the LCD about 6" x 4" or the monitor will do an "expand" to make the lo-res image fill the entire screen - when doing that it will get a bit fuzzy.  From my experience you may also have to adjust the little "fine adjustment" knob (thingy beside the de-interlace switch next to the video out port on the A3000) in order to eliminate the screen jitters.

Regardless, it will work and I'm sure you'll like the display.

-G

[Nagromme]

That's encouraging.

I wasn't sure how LCDs handled non-standard resolutions that don't appear in the specs.

I'd prefer big and blurry (I know what you mean), but small and sharp is fine too. Anyone know which way the Dell would go?

Regardless, anything that lets me ditch my Amiga's awful 15" (non-Amiga) CRT is good!

[glitch]

Hi,

     Yeah, there aren't many Amiga monitors left that look as crisp as the new ones available today.

     I don't know if you have had any issues with the screen "tearing" along the sides during screen refreshes at all.  But that little knob adjustment makes it disappear - that's most likely going to be the biggest issue you'll have - if at all.  Enjoy your new toy!

-G

[Matt_H]

There might be a setting on the monitor that allows you to choose. My old Thinkpad laptop can switch between 'strech' and 'small' modes. Don't know if stand-alone LCDs offer the same functionality though...

[Zac67]

All Desktop TFTs I've seen (~20) always expand the input to full screen. The A3k's NTSC interlaced flicker-fixed (non overscanned!) is rather similar to Standard VGA, so there's only little reason why the Dell should not be able to display the Miggy's output.

Sharpness is another issue: the TFT zooms everything to its native 1280x1024, so any other resolution tends to look fuzzy - BUT if you use PAL interlaced flicker-fixed (640x512) it should exactly double each pixel in height and width and the picture should be 100% sharp (NTSC will be slightly blurred vertically).
As the TFT's most probably not very familiar with that kind of signal it may be necessary to adjust its pixel clock and phase manually apart from using the Auto button.

[...]Looking at the docs shows a minimum vertical frequency of 56 Hz, so PAL's probably not an option, sorry...

btw: I wouldn't buy a slow TFT any more, the Dell's 20ms mean 50 Hz refresh - no flicker, of course, but anything faster than that will smear or vanish completely. Better get   at most 15ms for watching videos or less for gaming.

[Nagromme]

Thanks for all the help!

Two things I'm curious about:

1. What typically happens with the border (empty overscan region)? On a CRT you get a background color. Do LCDs show a stripe of that, or is it just gone? I'd think the LCD couldn't tell the empty area from the rest (since you can drag an Amiga screen down there, for instance) and so you'd get a big band of border color around your display. Which is OK.

2. What about if you ARE using overscan, in DeluxePaint, say. Will you get all the pixels on the LCD?

I've seen LCDs zoom, and I don't find it to be much softer than a CRT is anyway. Not as nice as native LCD, but I still think I'll be pleased compared to my old CRT :-)

Thanks for the PAL warning. I didn't think of that. I'll hate to give up my PAL shareware games! And my NTSC TV won't handle them either! I think there's a util for forcing NTSC though. I'll lose the bottom of the games but they may still run. Or is there some kind of hardware adapter that could double the Hz on the way to the monitor?

And when you say "slow TFT" are you referring to the 1905 I mentioned? Or another Dell that DOES handle less than 56Hz?

I've seen slower LCDs with fast motion and I don't expect I'll mind it the way some do. This Dell even got a good review for gaming. It seems that the ms number is only a part of the smearing issue, judging by user reports. Some units with a slower number get reported as having less smearing visible, for some reason.

But mainly, it's a 19" display with good reviews, features, and portrait ability... that you can supposedly get for $260 if you wait for the right Dell coupon!

Review:
http://www.anandtech.com/displays/showdoc.aspx?i=2332

[Zac67]

Nagromme wrote:
1. What typically happens with the border (empty overscan region)?

The border's usually out of the TFT's bounds so you can call it fullscan. The timing of the Amiga display is quite different (because of potential overscan), so it's really more a 768x576 (PAL) display with only 640x512 square used. Would be really interesting to see what the TFT makes out of that...

2. What about if you ARE using overscan, in DeluxePaint, say. Will you get all the pixels on the LCD?

Haven't ever tried it - now that I really think about it, I'd have to really take a TFT home...

I've seen LCDs zoom, and I don't find it to be much softer than a CRT is anyway.

Pretty much a difference, just take a look at 800x600 on 17"TFT (XGA) - 8^P On a 17" CRT it's 100% sharp.

Or is there some kind of hardware adapter that could double the Hz on the way to the monitor?

Like a 100 Hz TV set? Maybe, but you surely wouldn't want to pay for it...

And when you say "slow TFT" are you referring to the 1905 I mentioned?

Yes, it's spec'ed with 20ms and that translates to 50 Hz (1000ms / 20ms = 50 Hz) - the lower the response time the faster you see what's on the screen.

Or another Dell that DOES handle less than 56Hz?

Response time doesn't have anything to do with minimum refresh - and I wouldn't recommend Dell anyway...

I've seen slower LCDs with fast motion and I don't expect I'll mind it the way some do. This Dell even got a good review for gaming. It seems that the ms number is only a part of the smearing issue, judging by user reports. Some units with a slower number get reported as having less smearing visible, for some reason.

Yes, the smaller the response time, the better - see above.

[Vandelay]

Regarding response time:

Even though the general rule indeed says that the lower the response time, the better, you should be aware that the stated response time is not to be trusted blindly. As of today, there are no set standards of measuring response time, which means that the different manufacturers way of defining how fast, say, an 8ms panel in reality is, can vary greatly. In some cases you can discover that a panel keeps up to its 8ms promise on the grayscale, but when comes to certain colours, like red, the picture will smear like no picture on an 8ms panel should.

The only way of knowing how good these screens really are is by seeing them for yourself. If that's not possible, I would at least recommend reading a few independent reviews before deciding which one to go for (which it looks like you have :-)).

[PaSha]

One word of advice from personal experience with LCDs (and modern CRTs as well). Quite a few of them seem to prefer certain resolution/Hsync/Vsync combinations ('standardized stuff VGA, XGA, SVGA and so on), and might dislike oddball Amiga frequencies and resolutions even if they fall within the sync ranges (the software in the monitor itself is 'surprized' by the weird numbers and complains about the frequency being out of range). Standard VGA is 640x480x31 kHz/60 Hz, and IIRC there is also a 640x400x70Hz VGA mode. The same problem goes for some newer CRTs. Whereas my good old 17"CRT would happily display anything I threw at it that was within (and sometimes slightly ousite of) the sync range). Download the manual from the web, and you'll probably see a list of supported screenmodes.
You can perhaps buy it at a place that will allow you to return it within a few days for a full refund? Just in case it doesn't like your A3000.

-Paul

[srg86]

I use my A1200 through my Iiyama ProLite E435S TFT monitor and it does work fine, I mainly use Multiscan Productivity because it's 640x480. Still, because of the A3000's ECS graphics, I think that it wouldn't be really suitable because I think you'd get no more than a 64 colour palette.

As for tolerances, my TFT and my last CRT didn't have any, so a 29KHz horiz (e.g. DBLPal) scan was rejected (my 15" accepts it).

Also, I find that even with the 640x480 resolution, I can't use all of my screen. The windows and the mouse pointer are restricted to about three quarters of the screen width (all of the hieght). The rest is just the normal grey background colour. The Amiga does use it (it paints it grey) but doesn't let me.

Would an A3000 have this problem. It's odd as it's 640x480.

srg

[SyrTran]

@Nagromme

I just tried my 3000 in native modes (got a CV-64 in there, too) on my NTSC Samsung SyncMaster 150MP (15", 1024 x 768, 30-69KHz H, 56-85Hz V).

1.  As far as I can tell, the overscan region does display on the TFT.  There is a noticeable border on the edges of the screen.

2.  I don't have any overscan pics in DPaintV, but it looks like you'd see the whole thing.  The toolbox doesn't sit all the way to the right.

BTW, the "Display Enhancer" does a really good job of translating most of the native modes into a viewable format.  Only the Productivity Interlaced mode was out-of-range.

[Nagromme]

Thanks everyone, for many clarifications!

It sounds likely to work--maybe not certain, so I'll look into return policy.

The Amiga modes I'd most-commonly use are not listed in the specs--they're in the freq. range but not listed as pixel sizes:

320x200
320x400 (maybe rarely)
640x400
All at 60 Hz

(And PAL 320x256 games at 50 Hz are out of range.)