Amiga and BENQ BL912 / BL702A Monitors

[MartinW]

Hmm. I’ve been mulling something similar for some time. My GB-A1000 has a scan doubled output which then connects to an RTG board which then goes to the output. The RTG passes through the non RTG modes. It would be sweet if I could get scanlines on the non-rtg modes by using something like that between the scan doubler output and the rtg card.

[Jope]

Originally Posted by MartinW

Hmm. I’ve been mulling something similar for some time. My GB-A1000 has a scan doubled output which then connects to an RTG board which then goes to the output. The RTG passes through the non RTG modes. It would be sweet if I could get scanlines on the non-rtg modes by using something like that between the scan doubler output and the rtg card.

A scanline generator should work in this case.

[MartinW]

Incidentally, maybe that particular device can't do it (I don't know, I haven't looked yet but I assume not).

Originally Posted by Jope

You can't blank every second line where there is none. :-) So no, it won't be very useful on a 15kHz signal that hasn't been doubled to 31 first.

But you can if said device effectively scan doubles but does so by inserting the blank lines rather than doubling, no? That was my original thinking for the GBA, take the signal before the scan doubler. Then when I saw the question in this thread I realised in my case I could take the signal after the doubler and use something to suppress / blank every other line.

Well, made sense to me anyway - I could be spitting crap

[Higgy]

I have that scanline generator and a BL912.

I am sure I tried it on either an actual AMIGA or a FPGA AMIGA and the scanlines are not spaced correctly or it just did not work correctly. I guess its down to expecting 31kHz and only receiving 15kHz. - as per Jope's comment.

I looked for the generator last night to test again but it has been packed away.

I now get scanlines on VGA monitors from my modified GBS-8200 upscaler running custom firmware

[jbilander]

Originally Posted by Jope

You can't blank every second line where there is none. :-) So no, it won't be very useful on a 15kHz signal that hasn't been doubled to 31 first.

Ok, thanks, makes sense The reason I asked was...I looked at the Scart version at http://www.mmmonkey.co.uk/rgb-scart-scanlines/ and realised that it was almost the same circuit (and components) as that Vga-gadget, but maybe the scart one isn't working with 15 khz either, but it should right?. I read here https://www.systemerror.co.uk/2011/12/06/scanlines/ that it applies scanlines to the 320×240 image which is then scaled by the monitor or tv, maybe not the best result but it seems to work.

Anyway, the best result is probably achieved with an OSSC, but feels a bit expensive for only wanting scanlines on an Amiga->Benq combo.

I tried gbs-control with my Benq BL912 and couldn't get it to fill whole screen in 1280x1024 preset, worked better scaled to full hd but not as good as just using the RGB->Vga adapter, scanlines was nice though. Screenshots here:
https://shmups.system11.org/viewtopi...56354#p1356354

[Higgy]

jbilander - did you not use the GBS-Control web UI to expand/move the image to fill the whole of the BL912 screen?

My BL912 is also currently boxed up and stored away. Just using some old HP monitor that does not do 50Hz. Thankfully GBS-Control can force to 60Hz.

[jbilander]

Originally Posted by Higgy

jbilander - did you not use the GBS-Control web UI to expand/move the image to fill the whole of the BL912 screen?

Yes, fiddled with all the gbs-control settings as well as the monitors Auto adjustment etc...couldn't correct for the offset, the monitor reports 1680x1050@50 for the 1280x1024 preset Tried the gbs-control default 1280x960 res which works better, no offset, but picture not up to par with just using the adapter straight to the benq monitor 576i@50 IMO, but no scanlines then...which is why I started looking at the Vga scanline generator. I have the hdmi-version of gbs also, will try that one next with gbs-control and DVI input on BL912...

[caver99]

i have just tried the Acer V173 with mist cores at 15khz which were minimig, c64(which is extremity picky) and zx spectrum all worked flawlessly going to try with my consoles when i can as well.

[amipal]

Originally Posted by Nibbler

Color is : (i dont know if thats different for NTSC and its also a matter of taste but 100 is to strong imho)

Red=87
Green=80
Blue=84

Sharpness=1
Gamma,Brightness & Contrast somewhere in the middle, its a matter of taste and finetuning. (this can take a while....)
Pixelclock = 94 (any other value produces vertical scaling artefacts)
Phase = 20

Thanks for documenting this.
I was a bit concerned when I plugged my A1200 into the BenQ for the first time. I mean yes, it did display an image via the VGA-to-RGB adaptor, but the vertical lines and image placement weren't great.


I've used your settings (with only a couple of tweaks) and my display is now looking much, much better. Thank you!

[project23]

Originally Posted by caver99

i have just tried the Acer V173 with mist cores at 15khz which were minimig, c64(which is extremity picky) and zx spectrum all worked flawlessly going to try with my consoles when i can as well.

Interesting - i've seen people online say that the V173 doesn't work at 15khz... do ya know the specific model?

[CDTV1991]

Originally Posted by project23

Interesting - i've seen people online say that the V173 doesn't work at 15khz... do ya know the specific model?

I just received my V173 and it does not work. Its the one with a VGA input only

Money wasted unfortunately

[octavius]

Hi amiga funs, I need to decide which LCD buy to my Amiga 1200 from year 1994 I can't decide if 17" BL 702A or 19" BL912? Both have same resolution and 19" has dvi input etc all is knows... I'm interested which is more suitable? There is no problem with the price tag there is only 30€ more for 19" but if is better 17" for amiga no problem. I estimate if both have same resolution so 17" does have smaller pixels and nicer picture? I'm right? Thanks for some hint

[Tigerskunk]

Yep, you can just pick which one you'd prefer.

I went for the 702a because of pixel size, and "mobility".
I needed a monitor that I can put into a bag and take with me to meetups, etc..

I am really happy with my Benq.

[octavius]

Thx. I don't want to move lcd somewhere What is most important for me is quality of the screen. I have planety place on my desk so place doesn't play the role. If 17" is better I don't care I can buy 17"
Is anyone here who has both lcd? :-)

[jbilander]

With BL912 you have the dvi-input in addition to vga which is a big plus if you later for example want to install a Vampire or use a standalone Vampire with the same monitor, or if you want to use a cheap scart converter to run workbench in higher interlace modes without flicker. Both the Benq monitors flickers a lot in interlace modes. I did a dual setup with a splitter using both inputs to circumvent the problem, just switching between inputs on the monitor when I do wb-stuff vs gaming:

https://imgur.com/a/yrfX9Zm

https://github.com/jbilander/HowTos/...-simultanously

[solarmon]

I've got the BL702A and the on screen menu is very tricky/frustrating to navigate - there is no on screen display of the navigation buttons that lines up with the actual physical buttons.

It's quite easy to press the AUTO adjust button and you lose all your settings!

If I were to get another Benq monitor then I would consider the BL912 instead which, from looking at the manual, has a better on screen display and navigation.

[octavius]

Thanks guys for yours notes. I'll go to search 19"

[spudje]

I do believe the production of the BL912 has stopped, so it will be a bit harder to find a brand new one. The BL702a is still being produced if I'm not mistaken.

[ProdigalAmigan]

Originally Posted by octavius

If 17" is better I don't care I can buy 17"
Is anyone here who has both lcd? :-)

I may be late to respond but I thought I'd give my thoughts anyway.
I do have both of these monitors of which I bought the 17" BL702A first.
They both have their advantages and disadvantages...

BL702A

• Pixel size (making it somewhat sharper)
• Smoother scrolling than with BL912
• Less visible "banding" in 15Khz PAL mode
• Runs Multiscan (w/VGAOnly monitor profile) at 640x480 in Workbench 3.9

BL912

• Has a DVI port which can be used with a SCART to HDMI adapter with breakout sound to connect up a C64 to it with proper 4:3 aspect ratio maintained.
• Does run Multiscan BUT after experimentation found it does NOT save the screen adjustments/settings. However it does work VERY well with DblPAL+VGAOnly in WB3.9 and does then remember the settings you made.

Hope this helps.

//ProdigalAmigan

[idrougge]

I have no banding on either the 702 or 912. The trick is to adjust the pixel clock so that the bands become bigger, until the biggest band is wider than the entire screen.