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

[olePigeon]

@lameboyadvance @Trash80toHP_Mini I found this driver board, but It's for the IAQX10S LCD panel.  Only one of those on eBay, and it's a bit expensive.  The IAQX10M is the one that's so cheap.  I don't know if they're interchangeable.  If they are, then I just found a VGA driver board for the panel.  Since it's only a single VGA and not Dual VGA, then I'd assume it runs as 2:1 for 1600x1200.

 

[olePigeon]

@lameboyadvance @Trash80toHP_Mini The eBay seller says in the description that the driver board can be programmed for a specific LCD panel.  You email him/her about this driver board, and they can customize it for you.  I suppose if they're going to program it, maybe they can make it have 1:1 pixel mapping.  Wouldn't hurt to ask.

 

[lameboyadvance]

Hm, that does look like its just a bog standard LVDS controller board I've seen everywhere else. Kinda doubtful it can do full QXGA but at that price might be worth grabbing one anyway.

EDIT: I just unearthed my LCD panel, it is actually an IAQX10S. I'll guess I'll give that controller board a go then. Don't hold much hope in it though. Will probably just stretch 1600x1200 to 2048x1536.

 

[olePigeon]

@lameboyadvance  I'd be very, very, very interested in knowing how it works.  Especially at lower resolutions.

 

[Trash80toHP_Mini]

Ditto from me. Still leary about getting anything over 1920x1200 across an analog VGA setup, but nothing about this kinda crap is set in stone.

.  .  .  probably just stretch 1600x1200 to 2048x1536.

That'd be cool, a 15" 1200x1600 Portrait LCD would be right fine, but you'd probably be looking at 600 x 800 @60Hz from a fairly late NuBus Card. I've never heard of a PDS VidCard (pre-HPV) that could push that and not a lot of others that can do 60Hz VGA resolutions at all. I don't expect oddball Mac refresh rates to be supported, but you never know.

 

[olePigeon]

Radius GX 1600 and variants can all do 1600x1200 @ 32-bit.  I have the SuperMac version, but I don't use it because it can't do 4-bit color. :/

 

[Trash80toHP_Mini]

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:

 

[macdoogie]

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...

 

[jeremywork]

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

 

[Trash80toHP_Mini]

Thanks, good to know things are coming along since last I heard.

 

[olePigeon]

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

 

[macdoogie]

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.

 

[olePigeon]

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

 

[lameboyadvance]

...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.

 

[macdoogie]

@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.

 

[macdoogie]

...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.

 

[olePigeon]

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.

 

[olePigeon]

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.

 

[olePigeon]

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.

 

[CC_333]

@olePigeon That NEC does look nice!

I'm tempted to get it, but I already have a bunch of Acer, Dell and Apple screens, so I really don't need it.

c