Amiga.org

Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: murple on August 22, 2007, 01:51:31 AM

Title: Flicker fixer on CRT vs LCD
Post by: murple on August 22, 2007, 01:51:31 AM
I got myself one of these:

http://amigahardware.mariomisic.de/cgi-bin/showhardware_en.cgi?HARDID=361

I put it in my 1200 (I dont have the one with the 1200 specific design but the 4000 one works if you rip out the RF shielding and reposition the hard drive a few inches to the right... which sucks, since its just lying there, but it works. The VGA connector dangling outside the hole on the far right of the back is a bit cheesy too, but its what Ive got to work with haha).

Anyway, the image quality on it is fantastic on my old CRT VGA monitor. On my new LCD though, I have faint but annoying vertical lines up and down the screen (spaced about as far apart as, say, the character columns on a Commodore 128 in 80 column mode). Any ideas what causes this, and is it fixable? Id like to avoid using the CRT monitor for several reasons. Its huge and I only want one monitor (the LCD) on my desk, and more importantly, the display on the CRT is dark. Thats why I replaced it in the first place when it was my PC monitor. Even with the brightess and contrast turned all the way up, the hands at the beginning of the State of the Art demo are barely distinguishable from the dark blue background (which appears mostly black on this display).

If this is normal with flicker fixers, what causes it? I have a Commodore flicker fixer in my 2000 (based on the chipset in the 3000) but havent tried it on the LCD yet.
Title: Re: Flicker fixer on CRT vs LCD
Post by: murple on August 22, 2007, 02:04:44 AM
Also on some colors (like the blue of the WHDLoad startup screen) it seems as if between the lines there is a faint tiny checkerboard pattern with squares of at most a few pixels.
Title: Re: Flicker fixer on CRT vs LCD
Post by: amiga92570 on August 22, 2007, 02:18:41 AM
Yeah its awful isn't it. Try booting to a pal mode. I like the old crt's on the amiga, they look much better.
Title: Re: Flicker fixer on CRT vs LCD
Post by: Oldsmobile_Mike on August 22, 2007, 02:28:26 AM
Hi Murple,

Glad to know you're getting good use out of that flicker fixer  :-) .  Sorry I don't have any advice about getting it to work on an LCD monitor, the only thing I ever used it with was CRT's, but I've heard others mention Amiga output doesn't look as good on an LCD, either.  Have you tried other resolutions, perhaps?

Also, out of curiosity, did you ever get my message about the rest of that Amiga stuff I had?  Also, was still interested in checking out that AOL job board.  Let me know.  :-)
Title: Re: Flicker fixer on CRT vs LCD
Post by: vic20owner on August 22, 2007, 02:39:53 AM
Your LCD cant display Amiga resolutions without scaling.. so it's sort of like the filter mode in WinUAE... You can try playing with the clock setting on the lcd and see if it helps.

I remember being very dissapointed with the scan doubled display on my LCD monitor.
Title: Re: Flicker fixer on CRT vs LCD
Post by: murple on August 22, 2007, 03:21:12 AM
Hmm, I'll have to play with the settings and try to see if the LCD can be made to look OK. Otherwise I suppose I'll have to go buy/find a CRT monitor that doesn't have broken brightness settings.
Title: Re: Flicker fixer on CRT vs LCD
Post by: mbrantley on August 22, 2007, 03:40:32 AM
It has been my experience that LCD monitors only look good at their native resolutions and look varying degrees of terrible when scaling to other resoltuons. So a 1024 x 768 monitor provides crisp images at that resolution and no others, and same for 1280 x 960 or whatever. I ended up buying back a CRT display that I sold to a friend last year when I realized none of my LCD monitors looked so hot with any of my Amigas.

I wonder if a small LCD display would be good with an Amiga. Mine are 19 inches and larger. I've tried them with an A3000, an A4000 with CV643D card and an A1200 in DblNTSC and Productivity modes, but I didn't like the results.
Title: Re: Flicker fixer on CRT vs LCD
Post by: murple on August 22, 2007, 04:29:20 AM
I kind of wonder if one of those LCDs which do both TV and monitor displays would have more flexibility. My LCD monitor is small (17") and has a clock adjustment so I'll hook it back up later and see if I can get anywhere with it.
Title: Re: Flicker fixer on CRT vs LCD
Post by: vic20owner on August 22, 2007, 04:33:35 AM

Right, you want something which is a multiple of what you want to display... problem is only producivity mode (native) falls into this category at 640x480.  Everything else (scan doubled ntsc/pal) looks like crap.

I found that productivity mode looked excellent on my LCD monitor, but double ntsc did not... and it still flickered even with the scan doubler (worse actually).

I sold the scan doubler and bought a 1084s monitor.

However, I just picked up another scan doubler.. I wanted to try it with a CRT this time and see what I thought.

Title: Re: Flicker fixer on CRT vs LCD
Post by: murple on August 22, 2007, 05:39:13 AM
I've had a 1084S for a long time, got it originally for my C128. It looks great, except that A) WorkBench is much nicer in interlaced modes, and B) if you boot into PAL on it, the top and bottom of the screen are cut off in WorkBench (though demos seem to look OK). Also, Amiga RGB output is hard to feed into anything but an Amiga monitor... I need to hook mine up to a projector soon and my choices are either composite (eww) or VGA. Hopefully projectors dont have the same issue as LCDs haha.

However if you dont much care how WorkBench looks, an 1084S is a damn fine monitor.

That said, both the A1200 and A2000 with different kinds of internal scan doublers look fantastic on my CRT. Or rather, they look at least as good as when my PC was hooked up to the same monitor, perhaps slightly better color. As said earlier this is a cheap ass monitor that has always been incapable of sufficient brightness/contrast when displaying darker images. So Im sure on a good CRT the display would be excellent. The image is crisp, theres no blurriness or flicker or other visual weirdness. Since you can get CRT monitors for dirt cheap now, it should be possible to get a nice large monitor for the Amiga that dwarfs any original Amiga monitor. (Those maxed out at what, 15 inches?)
Title: Re: Flicker fixer on CRT vs LCD
Post by: hamtronix on August 22, 2007, 12:15:57 PM
I want to plug the 9 pin out of my FF directly into a monitr for convenience sake. These monitors just poped up on Craigs -  

Samsung Syncmaster 550s
AOC Spectrum 7vlr
Samtron Low radiation (I think this is an older model)

Does anyone have any suggestions or experience with any of them? The best would be plug it in go to interlaced mode and start Amiga-ing around...

Thanks!
Title: Re: Flicker fixer on CRT vs LCD
Post by: vic20owner on August 22, 2007, 02:48:55 PM
My 1084s actually looks better than my LCD... a lot better.  Interlace mode looks great but there is a small amount of flicker which isn't too hard to hide by reducing the contrast.

Problem is I don't expect my 1804s to last forever... it's already a little dark compared to a new monitor.

Title: Re: Flicker fixer on CRT vs LCD
Post by: murple on August 22, 2007, 03:35:36 PM
You sure youve got a 1084S there vic? haha... Mine, the flicker is unbearable in interlace. Same on any RGB or composite monitor or TV. You may be able to somewhat mask it by changing contrast, but prolonged viewing is likely to give you eye strain and headaches. Good luck with that... I dont think you could pay me enough to run interlace without a flicker fixer for more than like 5 minutes at a time.

Also, I expect my Commodore monitors to last just about forever. Even the oldest of my Commodore monitors, the old boxy brown rainbow badged C64 monitors, looks better than many new CRTs. Its far crisper than my new TV, and if the screens were bigger I'd hook one up to replace my TV. I fully expect my 1084S and 1902A to go on functioning as my C128/64 and backup Amiga monitors for many more years to come.
Title: Re: Flicker fixer on CRT vs LCD
Post by: CLS2086 on August 22, 2007, 08:31:09 PM
You can always change all the capacitors to extend your 1084 life and get a cleaner picture !
Title: Re: Flicker fixer on CRT vs LCD
Post by: Zac67 on August 22, 2007, 09:12:22 PM
As has been said before, a TFT output looks best with a signal in its native resolution or a multiple of it.

An SXGA (17 or 19") TFT should look OK with the Amiga's somewhat VGA output (at least in PAL) - as long as the monitor can cope with the low vertical scan rate. I'm quite satisfied with the output quality of my Merlin RTG in 800x600 on my 19" Samsung. PAL flicker fixed (A3000) looks pretty nice, too.

I did have to adjust the monitor quite a bit though, auto settings didn't work at all due to the exotic timing. To get the best output possible: Disable all overscan. Display some text, some diagonal lines and a fine checkerboard pattern or vertical lines, everything in full width if possible. Then adjust the 'clock' until the vertical bands get as broad as possible. Finally change 'phase' to gain sharpness.