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olePigeon

QXGA LCD Panels now cheap ... good enough for variable resolutions?

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Yep, I've got the GX 1600, but those are very tail end of the NuBus era. outside of Apple and Radius versions of the 24AC, 800x600 @60Hz seems pretty thin on the ground. A few will do 1024x768 @60Hz like the Futura II cards. Dunno, we'll see what we see. :approve:

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Note that from my reading of the QXGA Panel data sheet referenced in an earlier post, that display is what is called a "Dual-Link" LVDS. It needs 8-lanes to achieve that resolution. Regardless of the interface, TFT panels themselves will only accept data at their native resolution. Any scaling would have to be done by external circuitry on those adapter boards. Also note that while many of these "everything-in-one" adapter boards which accept VGA/Composite/S-video/DVI/HDMI may look the same as each other, there is still a bit of programming done on the board to adapt it to the target display. Most of these boards I've encountered are based on a conversion chip made by RealTek(The chip with the crab icon on it) which is actually quote sophisticated and also includes the On Screen Display for menus for brightness/contrast/etc. I don't recall off the top of my head whether they have a dual-link LVDS version of that chip.

 

All older panels that are LVDS or TMDS require dual link to do resolutions higher than 19x10 or 16x12 IIRC. That's why newer standards such as MIPI and Display Port were invented. They use a higher data rate to get more pixels with less data lanes. I was actually surprised to see mention of "Old" machines with QVGA, until I remembered that Dual-Link(Sometimes called Dual-Channel) was a thing...

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On 11/22/2019 at 8:57 AM, Trash80toHP_Mini said:

1920x1200 (WUXGA) is a hard ceiling for Analog VGA

FWIW, I'm not sure VGA has a defined ceiling, it's just limited by the bandwidth of the DACs on either end (or the speed of the CRT electronics.) The resolution and refresh rate will also be limited by the size and speed of the frame buffer, but the later model PCI/AGP Radeons can provide many of the higher bandwidth resolutions to some of the later classic macs. I've got a Sony FW900 that I've driven at 2560x1600@60hz over VGA, so there's definitely no limitation of the cable itself :)

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7 minutes ago, olePigeon said:

Darn.  They can't do a custom driver board for the IAQX10M. :(  Only one they have is for the IAQX10S.

Who are "They" that you refer to? From the looks of it the M is just a 200nit brightness panel compared to the 150nits of the S variant. If the BLC is also on the driver board, I would think that some component substitution could be done to accommodate whatever variance in voltage or current is needed for the brighter panel. Scratch that. I just realized that these are CCFL and not LED. There could be considerable differences in the Backlight Controller. I've actually never done a BLC for a CCFL panel myself. I know the voltages are much higher than for LED. I once singed my finger(made a sizzling sound and left a burn) on the inverter for the first 15" iMac.

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...So the difference between the IAQX10S and IAQX10M is just the backlight? In that case couldn't you just use an alternate backlight driver board? The hardest part is driving the LCD itself, the backlight just needs something providing the right stepup voltage.

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2 hours ago, olePigeon said:

@MacDougall "They" are a company in China that can program a custom driver board for most LCD panels.  Just not the one I wanted. :(

Ah, thanks for the clarification :) If you have a link to the driver board, I may be able to provide some insight. I have a lot of experience with TFT displays(about 5 years) from 1.5" OLEDs to 10.4" TFTs. I just don't have any direct experience with CCFL BLCs.

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1 hour ago, lameboyadvance said:

...So the difference between the IAQX10S and IAQX10M is just the backlight? In that case couldn't you just use an alternate backlight driver board? The hardest part is driving the LCD itself, the backlight just needs something providing the right stepup voltage.

Can't say that for certain, as I was just comparing the high level specs. However, in general, when the part number is exactly the same but with differing suffixes, the differences are usually just variants of the backlight and/or the polarizer stackup(to trade off contrast/viewing angle, etc) or even just "matte" vs glossy top film. Since this display appears to have the same interface and resolution, I would suspect that the LVDS interface is driven the same way for both. If I could dig up the data sheet for both, I could be a bit more certain.

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After many, many hours of searching, I finally found an LCD display that should work.  The NEC LCD2090UXI is a 20" 1600x1200 display that offers:

  • EXPANSION: Selects the zoom mode.
  • FULL: The image is expanded to 1600 x 1200, regardless of the resolution.
  • ASPECT: The image is expanded without changing the aspect ratio.
  • OFF: The image is not expanded.
  • CUSTOM: Refer to the ADVANCED OSM Controls section of this user’s manual for detailed instructions.

So that's exactly what I'm looking for.  Now to see if I can find one or one that's equivalent.  A 1600x1200 display would be pretty sweet.  Only concern I have is whether those options are available over VGA and not just DVI.

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Looks like their 19" version also supports it and is more common.  Someone even has a bunch of loose monitors for sale.  A bit worried about dead pixels and scratches.  Wouldn't hurt to ask.  $50 shipped isn't too shabby.

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Well, I think I found my ultimate monitor.  Actually found one on Craigstlist, but it's on the other side of the country in New Jersey.  Gonna see if they'll ship.  There're quite a few on eBay, but they're all black.  I might get a black one for my DOS PC, though, even though I really like my little 15" IBM.

 

NEC LCD1980SX.  Man that's a nice looking screen.  And it allows you to disable image expansion.  I went through several dozen different monitors on eBay.  Only other monitor I found that had the same options was the SONY LMD-1950MD.  None of the "Professional" Dells or even VueSonic did it.

 

1980SX.png.ad88b899f2b91e177e64c90446f0f82d.png

Edited by olePigeon

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@jessenator  Nope, that's the MXP model or whatever it's called.  I thoroughly searched the user manuals for various different NEC models.  That one doesn't have the Expansion feature that I want.  It only has the usual adjustments for Clock, Phase, and Vertical/Horizontal movement.  But nothing for scaling.  Seems like NEC had a very select range that supported the Expansion option.

 

The SONY LMD-1950MD led me down a tangent for Medical Displays.  I found several GE USE1913A monitors, but I could NOT find manuals. They were bundled with patient monitoring systems, and the manual for that device didn't cover the OSD controls for the display itself.  So I have no idea if the GE Medical Display would suit my purposes.

 

Wouldn't mind knowing since there are a bunch of them on eBay for relatively cheap.  I may have to fall back on the Black NEC, but was hoping for a nice white, beige, or platinum colored panel to match my computer.

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22 hours ago, olePigeon said:

After many, many hours of searching, I finally found an LCD display that should work.  The NEC LCD2090UXI is a 20" 1600x1200 display that offers:

  • EXPANSION: Selects the zoom mode.
  • FULL: The image is expanded to 1600 x 1200, regardless of the resolution.
  • ASPECT: The image is expanded without changing the aspect ratio.
  • OFF: The image is not expanded.
  • CUSTOM: Refer to the ADVANCED OSM Controls section of this user’s manual for detailed instructions.

So that's exactly what I'm looking for.  Now to see if I can find one or one that's equivalent.  A 1600x1200 display would be pretty sweet.  Only concern I have is whether those options are available over VGA and not just DVI.

T85A (AKA  part # 9519-AW1 ) from IBM has this feature.   It can display resolutions as either expanded to full LCD resolution, or just fill the pixels on teh screen that correspond to the original resolution.   It only goes up to 1280 X 1024 though.

 

I'm not sure if it has the "ASPECT" feature listed above though.  Or put it another way, I know it has either ASPECT or FULL, I'm not sure it has both.

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4 hours ago, olePigeon said:

NEC LCD1980SX.  Man that's a nice looking screen...

 

1980SX.png.ad88b899f2b91e177e64c90446f0f82d.png

A word of warning: Those NECs mentioned above are a decade and a half old now. I have one of the 20" 1600x1200 ones in the garage that I trashpicked because, yeah, at first glance it looked awesome featurewise, but it didn't take me long to realize that there has been a *lot* of water under the LCD monitor bridge since those were made. Not only is the "best case" color reproduction and contrast of the LCD not that great, there's a good chance that a used one has a *lot* of miles on the old CFL backlight. I would strongly recommend seeing a monitor of this age in person before ponying up any money for it. There's a fair chance the display will leave a lot to be desired.

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@Gorgonops  I get what you're saying.  I'd get a brand new monitor if I could find one that supports those features.  Right now I'm just going through eBay looking at every single 4:3 and 5:4 monitor and Googling for the manual.  I'm hoping maybe I'll be able to find a new one.

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Edit:  It's only on their widescreen displays. :/

 

Custom Scaling (select models) Selects the method on how displayed information on the monitor will be formatted. Select:

  • Fill to Screen - image fills the entire screen and may look distorted or elongated because of nonproportional scaling of height and width
  • Fill to Aspect Ratio - image is sized to fit the screen and maintains proportional image
  • One-to-one - disables video scaling, displays an image that is smaller in size than the monitor’s capability and centers the image on the screen in the active viewing area

 

I'm thinking that perhaps having a small database of LCD monitors that support this feature would be useful to not just Mac users but any vintage computer user who wants 1:1 pixel mapping on a monitor.

Edited by olePigeon

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I wonder if searching for an LCD controller from the PiVerse with these features might be taking a look? Might, retrofitting just about any LVDS panel display with a more capable controller be a way go?

Edited by Trash80toHP_Mini

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1 hour ago, olePigeon said:

@trag 1280x1024 is perfect.  Unfortunately that model IBM panel appears to be pretty rare.

Yeah, after they cleared out from their first use owners, they seem to have disappeared from the market.

 

There was one reseller who had stock, but they seem to have run out a couple of years ago.  

 

I picked up a few of them for a song (compared to new LCD prices at the time) several years ago.   Feature-wise, they are fantastic.  Also, brightness is very even, but dimmer than new LCDs.  

 

I may pick out the runt of the litter and try replacing the backlight tubes on it and see how that goes.

 

I'm kind of surprised that the One to One feature is so hard to find, given how common it was in teh early days of LCDs.   I guess there was more need then to support older resolutions.

 

Newegg often has refurbished 1280 X 1024 LCDs from HP and Dell for about $50 each.   It might be worthwhile to check the manuals on those models.

 

https://www.newegg.com/dell-p1914s-19-sxga/p/N82E16824260224

 

https://www.newegg.com/p/0JC-0004-00HW5

 

https://www.newegg.com/hp-la1951g-19-sxga/p/N82E16824276607

 

That last one is $90, but I've seen it on sale for about $50.

Edited by trag

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26 minutes ago, trag said:

I may pick out the runt of the litter and try replacing the backlight tubes on it and see how that goes.

I was parting out a 17" display just to be rid of it because it was too dim.***** All I wanted were the speakers, but it turned out the backlight sheeting was fine. Could adaptation/cannnibalization be reasonably straightforward in your case? I've always wondered if those sheets could be cut down from two sides and retain function of the reduced size panel?

 

1 hour ago, olePigeon said:

Edit:  It's only on their widescreen displays. :/

 

Custom Scaling (select models) Selects the method on how displayed information on the monitor will be formatted. Select:

  • Fill to Screen - image fills the entire screen and may look distorted or elongated because of nonproportional scaling of height and width
  • Fill to Aspect Ratio - image is sized to fit the screen and maintains proportional image
  • One-to-one - disables video scaling, displays an image that is smaller in size than the monitor’s capability and centers the image on the screen in the active viewing area

 

I'm thinking that perhaps having a small database of LCD monitors that support this feature would be useful to not just Mac users but any vintage computer user who wants 1:1 pixel mapping on a monitor.

Check out the specs of the HP PL766A I shared it between HP_Mini and the VGA capable Macs on the display. THaven't looked for the manual yet, but title looks promising anyway?

https://h10057.www1.hp.com/ecomcat/hpcatalog/specs/provisioner/99/PL766AA.htm

 

 

*****Now I've got a 17" lightbox, at least I got rid of the stand and it fits flat on top of other stuff in one of the storage boxen. ::)

Edited by Trash80toHP_Mini

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