Amiga and BENQ BL912 / BL702A Monitors

[turrican9]

So what we need now is a cheap scanline generator that works between the RGB and these screens. They need to support the 15KHz mode properly. The ones I've seen so far are made for 31KHz. Actually have one I bought on ebay. What happens is if I try it on 15KHz mode the scanlines get too thick.

I have a couple of Indy ECS units to. They support both 15KHz mode and scanlines but the problem is that these units will not save the settings properly. And they are not completely stutter free at 50Hz. This is why we need a cheap, simple scanline generator to put between the RGB and our BL702A/BL 912 screens

[idrougge]

Doesn't Productivity or Multiscan work?

[wazza]

Productivity is probably the best of a bad bunch. But no matter how much I tweak the settings I can't eliminate vertical lines. Multiscan kind of works but the image is quite distorted and again i can't get rid of the lines. To be honest, I have now given up and gone back to a Samsung LCD TV with a SCART input which, now I have investigated the picture options a little more closely, does a far better job and deinterlaces nicely.

[idrougge]

Funny, I like my Samsung tv because it doesn't deinterlace. It's not easy to try to debug graphical effects on a deinterlaced screen.

[TheDarkCoder]

Hi,

does anybody have the datasheets for the BL702A and BL912?
In particular I'd like to know the maximum Line Frequency, to evaluate how good are they with a Cybervision64

[amigasith]

I've been looking for the BenQ BL912 specs for myself for quite some time and the most detailed information I could find was in German Here is a link to the data sheet ("Datenblatt") of the BL912: http://www.benq.de/product/monitor/bl912/downloads/

The line frequencies are: 31 ~ 83 kHz / 55 ~76 Hz (sorry but that's all that's there)

Hope this helps

[TheDarkCoder]

Yes!
many thanks amigasith

On the same site there is also the datasheet for the BL702A.
According to those datasheets, they accept the same range of frequencies

I am choosing one of them, so one less parameter for comparison

[Dajo]

Hello! I recently bought a BL702A to use with my A1200 and my A500.

As stated earlier in this (old) thread the BL702 on A500 gives a perfect picture out of the box without changing any settings.

But I am having som trouble with the A1200. The only screenmode that gives acceptable sharpness/flickering is PAL Hires, though no way near perfect. The biggest problem is that the colors are strange. Everything has a obvious purple/blue hue to it.

All other screenmodes are really flickery and overall strange.

Anyone else here having the same problem?

David

[demolition]

Originally Posted by Dajo

The biggest problem is that the colors are strange. Everything has a obvious purple/blue hue to it.

Sounds to me like you might be missing the green color channel?

[Dajo]

The thing is that the monitor displays the colors right when i use other screenmodes than PAL hires. But all the other screenmodes are flickery..

I've just bought a BL912 and am using that fine with an A1200.

Don't know about the BL702 but the 912 has no de-interlacer built in so any interlace screens will flicker.

Personally I'm using the dblpal mode as it fits the screen best. With the Mulsitscan I have to fiddle with overscan and move the workbench screen around.

I am not getting any lines though. Can't say the picture is pin sharp as the Amiga cant disply the native 1280x1024 but it's certainly clear enough.

Chris

[demolition]

I don't think any LCD monitors will deinterlace the input from the VGA port since interlaced VGA was never really a thing.. It needs a SCART input for that.

[Jope]

Originally Posted by demolition

since interlaced VGA was never really a thing..

Sure it was, back in the 90s the cheaper PC GFX cards and monitors couldn't do 1024x768 as progressive, but they did manage it as interlace. :-)

[Dajo]

Originally Posted by GrievousBee

I've just bought a BL912 and am using that fine with an A1200.

Don't know about the BL702 but the 912 has no de-interlacer built in so any interlace screens will flicker.

Personally I'm using the dblpal mode as it fits the screen best. With the Mulsitscan I have to fiddle with overscan and move the workbench screen around.

I am not getting any lines though. Can't say the picture is pin sharp as the Amiga cant disply the native 1280x1024 but it's certainly clear enough.

Chris

Thanks for your input.
I think I have found the reason I'm getting strange colors. After some troubleshooting I have found that the most probable cause for the purple hue is that the videodac is broken. Some nuances of green are not being signaled from the dac.

David

[demolition]

Originally Posted by Jope

Sure it was, back in the 90s the cheaper PC GFX cards and monitors couldn't do 1024x768 as progressive, but they did manage it as interlace. :-)

Yes, I also tried interlaced back then since I had one of those cheap gfx cards but it was horrible to look at so I switched back to lower-res progressive.
What I meant was that I never saw anyone use interlaced modes with VGA cards. There was only a very short window where using interlaced could make sense on a PC as the tech quickly moved on.

[Jope]

You're probably right. I think I remember one guy who ran his in interlace to get 1024x768, but no-one else. :-D

[Estrayk]

Maybe can be interesting.
Some people wants know how is the speed switching between DVI input, to VGA input on BenQ BL912 Monitor.

[ Show youtube player ]

[neumanix]

About the screen centering with the BL702A, is that needed every time you switch
between hires and lowres?
That would get old pretty fast if you're coding some lowres stuff in a hires IDE.

[dodke]

Originally Posted by neumanix

About the screen centering with the BL702A, is that needed every time you switch
between hires and lowres?
That would get old pretty fast if you're coding some lowres stuff in a hires IDE.

Late reply but anyway. NO the centring and other settings are stored per screen mode and all PAL modes seem to be exactly the same. Switching between hires and lores is completely instant.

Changing between NTSC / PAL / double PAL etc takes a few seconds.

Some games and demos of course are not necessarily centred correctly but you'd have that on any monitor.

[dodke]

Btw if anyone is wondering which hires non-interlaced mode to use for Workbench etc, Euro72 seems to work pretty well. All other 30+khz modes I've tried had some vertical lines that I couldn't get rid of but not on that.

The resolution is only 400 pixels high and it's got a bit of a tall and narrow look but otherwise it looks good. Artefacts are minor, nothing like on dblPal or multiscan.