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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: dandelion on May 29, 2007, 10:49:21 PM
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Hi all,
Have just picked up an aging LCD monitor, a Medion 7514 model. I had little hope of it being able to display native 15khz Amiga output but thought i'd give it a try anyway. On startup I was suprised / overjoyed to see the purple screen and floppy disk animation! But, a floating message soon appeared saying "Signal Out of Range : Set Monitor to 1024x768 60hz". There seems to be no way to get rid of this. Does this mean that the monitor can't display this screenmode safely, and on most monitors this would be blanked out? Can I alter the settings somehow to get rid of this error message? Also - when this error message is displayed I can't access the monitor set up controls. None of the buttons work. I've plugged it into a standard SVGA outputting machine and it works fine, and I CAN access the set up pages. I've tried selecting a 60hz mode (well, it says this is already selected), but it makes no difference when trying again with the Amy.
Any ideas, experiences related to this? Am I damaging the monitor in getting it to display something so lowly as a 15khz display?
Cheers
Dandelion
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Try a scan doubler. I have never tried to hook an LCD to my Miggy.
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On my Shuttle XP17 I get a similar error when using PAL modes. A quick off/on and the message disappears after about 10 seconds. Worth a try at least.
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Have you checked all the settings on the monitor while connected to a PC for a way to disable that message? Most LCD's I've seen have that option, but maybe yours is old enough that it doesn't.
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The same thing happens on my LCD monitor with the out of range message floating over the display but, unfortunately, not for native Amiga modes which just give me a black screen with the message. I was looking at an LCD monitor recently which synced down to 24khz but nothing close to 15khz.I will have to keep the brand of your monitor in mind.
The out of range message is in the firmware of the monitor. Since each monitor has it's own firmware, it might well be possible to disable the message. I haven't been motivated to try it on mine since displaying 1024x1280 on a 1024x768 default monitor results in painfully small out of focus text. It might also be possible that the monitor is electrically stressed by the 15khz signal even though it can display it and this triggers the message. You can zap CRT monitors with the wrong video signal but I'm not sure if this applies to LCDs. Crt monitors use high energy levels and dangerous voltages but LCD monitors are low energy devices
I've found the best Amiga resolution on my lcd monitor is 640x480. It can go up to the full 1024x768 resolution but it looks much better at 640x480 and my RTG card does a beautiful 24 bit desktop at this resolution. I've also found that I can get a decent dblntsc 640x400 workbench at 29khz and that I can run Deluxe Paint and Brillance in dblntsc and multisync AGA HAM modes on my lcd monitor which is real cool. Dblntsc seems to work better even though the multisync modes include 640x480. Since you have an A1200, this should work for you. You might have to use dblPal instead of dblNTSC if you have a Pal system.
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As many monitors barf at 50 Hz and start just at 56 Hz do try to boot into NTSC to see if it works better.
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The monitor tells you to better use its native resolution since all TFTs can not produce sharp output in any other resolution. I'm pretty sure there's some menu item to get rid of this message.
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All the TFT's I've used (4) haven't had option to disable this message. Most have option to specify location of the OSD display, though.
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Piru wrote:
All the TFT's I've used (4) haven't had option to disable this message. Most have option to specify location of the OSD display, though.
my eizo doesn't allow you to move the OSD off the screen unfortunately...but my samsung allows me to have 100% transparency lol
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On my Shuttle XP17 I get a similar error when using PAL modes. A quick off/on and the message disappears after about 10 seconds. Worth a try at least.
Are you saying that the Shuttle XP17 CAN do PAL resolutions, through the 15-pin VGA connector WITHOUT a scandoubler???
That would be sweeet!
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Actually - thinking about it!! I think there is an "OSD" option in the setup menu. Will play with that this evening.
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Okay, well. Got home, plugged the monitor into my Acorn (which gives SVGA out) to access the on-screen display. The "OSD" option within the menu allows you to control the horizontal and vertical position of the OSD menu, but not warning boxes it seems. When I plug the Amiga back in, it's just as before. The only options I don't understand are "clock" and "phase" which i'd think have some low-level frequency adjusting ability. Anything of value there? Otherwise I think it's going to be 31khz only :(
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Most of our Belinea and NEC monitors have options for turning off OSD.
Clock and phase are parameters to adjust the timing of the video input to the (static) LCD matrix. Since it's a digital display (essentially a large memory chip where you can actually see the stored data bits), the analogue input needs to be digitized/sampled and if the sampling rate (clock) doesn't match or the sampling takes place between pixels (phase) the display is blurry and may even show noise (flickering pixels).
Because the Amiga's output timing is in no way common to the industry, you may have to adjust those values manually:
- if possible set the video output to the TFT's native resolution or something with a simple ratio, e.g. 800x600 for a 17/19" 1280x1024, makes roughly 2:3 (OK); 640x480 is 1:2 (better); very bad is 800x600 on a 15" 1024x768
- display something with high contrast & lots of detail, full screen, a lot of small text will do
- change the 'clock' value to get rid of vertical stripes
- change the 'phase' value to get the sharpest possible display
- if you're not using the native resolution, there's no way to get a really sharp picture
Because this is prone to error (even when done automatically) it's much better to use a digital DVI input - the display is always perfect.
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@amigakid
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Try a scan doubler. I have never tried to hook an LCD to my Miggy.
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That would miss the whole point of his joy! he is or could be very happy because it displays 15khz Amiga modes without the need for a scan Doubler.
If anyone is interested.............I have purchased an INFOCUS DLP projector that works with Amiga extremely well and even had a Flickerfixer/De-Interlacer for 15khz modes! all through the S-Video portif you have s-Video out on your Amiga. It might work through Composite as well. The only thing is that it displays PAL in Black and White i your Amiga is NTSC and I suspect Vice versa if your machine is PAL.
This projector cast me $650 brand new plus a $200 rebate! so its $450.
You get:
1. A large screen TV
2. A FlickerFixer
3. A Monitor
all in one with multiple inputs for Component, S-Video, Composite.
I got to look at the model number as it slipped my mind.
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The monitor tells you to better use its native resolution since all TFTs can not produce sharp output in any other resolution. I'm pretty sure there's some menu item to get rid of this message.
Not all LCD monitors are created equally. Mine is a Phillips Magnovox LCD TV/Monitor with VGA, composite, and s-video inputs. Native resolution is 1024x768 but it does 800x600 and 640x480,640x400 and 320x240 just as well and switches between these resolutions like a CRT. It can handle dblntsc modes too--some better than others.It is also excellent for watching movies and can handle both NTSC and PAL video. I have had to do quite a bit of tweaking of the Picasso 96 drivers for my Merlin RTG card to work properly in all these modes but the monitor hasn't required much tweaking at all to work with my A4000. Had to adjust the vertical position of DBLntsc modes a little and that's it. Every now and then, the display will come out distored or out of sync but when this happens, all I have to do is turn the monitor off and on again and it readjusts itself. The only mode that required some serious tweaking is Atari ST mono 640x400. That required some radical adjustment of the clock and horizontal position controls but the resulting display is excellent. And once I made the adjustments, the monitor memorized my settings and I don't have to readjust after using it with my Amiga.
On the other hand, the laptop I'm using now can only do it's native 1024x768 resolution properly and I have another laptop that does it's native 1280x1024 and 640x480 equally well but everthing else is pathetic on it.
Since the monitor accepts 15khz composite and s-video, it has occurred to me that it must have some sort of internal scan doubler/video scaler. I have seen some hardware hacks for this monitor floating around the net--adding component video inputs for hdtv as I remember.
:roll: :roll:
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An LCD display that takes analog input needs some kind of transformation of the video stream. Take continuous ("analog") picture in -> convert and put out to lcd discrete (digital) native resolution. LCD pixel data can be updated as slow as you want, even static, because it is not based on the afterglow by beam hitting the phosphor on CRT surface. (AC voltage is necessary to drive the LCD element, but that is at the output driver stage. At least with the simple "black(opaque) and white(transparent)" LCD)
It shouldn't make much difference if the input is "15 kHz" or the higher beam return sync rate used in PC CRT:s. The process of conversion used by the LCD monitor should remain the same, only it should accept a wider range of input signal sync frequencies.
That is what I am guessing.
Why don't all LCD-monitors accept 15 kHz, is because they are made by big evil companies who just don't care. :cry:
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You're right in most parts. I think the reasons for not supporting 15kHz modes on LCD monitors are:
- composite/component video requires additional electronics, RGB input is not common outside of Europe (Scart)
- nearly all video sources are interlaced, proper de-interlacing (including removal of comb effects) requires lots of additional logic
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to avoid confusion (or to add some)
an LCD monitor is a thing while a LCD TV/Monitor is all another matter.
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Framiga wrote:
to avoid confusion (or to add some)
an LCD monitor is a thing while a LCD TV/Monitor is all another matter.
The same basic technology. The LCD TV/Monitors generally come with VGA inputs and the same resolutions as LCD monitors--at least the 15-19 inch models. They have wider viewing angles than LCDs dedicated to PC use and more circuitry to decode video. Because of the composite and S-video inputs, they are much more suitable for Amiga use. My impression is that they are VGA monitors with NTSC/PAL decoding added and not the other way around--Video monitors with VGA added. Because they have to deal with video resolutions, they seem a bit more flexible in what they can deal with resolution wise than dedicated PC LCD monitors. Of course there could be wide variations between brands and models and you Europeans are so fortunate in having SCART rgb inputs.
I've sold off all my 1084 monitors now that I have the LCD monitor and am quite happy with it.
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You could try an Amiga D23 to VGA (HD-D15) adapter, and see if the LCD (monitor only without TV related add-ons.) syncs to it, using analog RGB input. Sometimes you might get lucky, if the designers have had some foresight to think about marginal groups of users. :lol:
But if you want to use interlaced screen modes, an LCD TV/monitor is more likely to work, because the LCD monitors desgined for PC:s may not support interlaced modes, because they are rarely used on PC display controller cards (I think.)
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14.32Khz (or 15Khz rounded up) is essentially the same NTSC/PAL rate signal that the Amiga original chipset sends out all it's resolution modes in. An LCD TV that supports a 15Khz VGA mode may be possible because analog TV is usually at that same rate..
Most LCD TVs and monitors can adapt to different rates or be programmed for them. However I suspect the message is there because it isn't programmed for the rate, even though it's able to do it..
Most LCD Monitors are set for 28 Khz or Higher (those that are not tv's) because most modern VGA cards did resolutions from 28-31 (640x480 to 800x600). The original Amiga chips weren't designed at all to handle those frequencies and worked with the rate that the original PC RGB (pre-VGA monitors) did for CGA (but analog instead of digital for more colors, which was the same resolution).
I'd check with the manufacturer to see if you can program rates. I know my monitors from Olevia-Syntax are programmable.
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I've tried connecting an Amiga directly to my monitors VGA input. Doesn't work. Just a black screen with an "out of range" warning message. This is what leads me to believe that it is basically a VGA monitor with a built in scan doubler, video scaler to handle the composite and s-video inputs. You can buy external video scalers that convert video to vga and the low end ones are not very expensive. Also, it's native resolution is 1024x768 XGA and not 720x480 or 720x576 DVD video which indicates an internal video scaler.
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DonnyEMU wrote:
14.32Khz (or 15Khz rounded up) is essentially the same NTSC/PAL rate signal...
PAL & NTSC horizontal scan rates range from 15.625 to 15.75 kHz. ;-)