Optimal Flatscreen monitors for QL and Q68

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Peter
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Optimal Flatscreen monitors for QL and Q68

Postby Peter » Sat Apr 13, 2019 10:37 am

Some may be interested in a flatscreen monitor that suits both the QL and Q68 equally well. Therefore I start a separate topic, not just appended it to Q68 or QL video threads. My personal requirements were:

  • 4:3 screen format, because this was the original QL look, no widescreen
  • Between 12" and 15", because that was the historic size, and is portable
  • HDMI input, supporting the QL via the common, nicely cased black SCART/HDMI converter
  • VGA input, supporting the Q68
On my wishlist also was:

  • Native 1024x768 resolution because that ideally fits the Q68, and 512x256 can be scaled without blur
  • Optional support for the QL via the GBS8220 V3.0 and V4.0 video converter
  • Analogue stereo audio input for the Q68
  • Available new

Thanks to Tobias' advice, I turned my attention to Chinese models and found:
Eyoyo 15" TFT-LED Monitor 1024x768, Model: EM15A

I'm quite happy with that one, because it fulfills every point. And for the first time I got an acceptable picture from the original QL via converter.
The HDMI converter provides better quality from the QL than the GBS8220, but both work.
With the Q68, the picture is crystal clear, best I ever saw. Sound quality is very limited, not enough bass. But at least stereo.
It can save space by switching between QL (HDMI) and Q68 (VGA) without extra box.

More feedback, models or experiences would be good to know.


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Re: Optimal Flatscreen monitors for QL and Q68

Postby dilwyn » Sat Apr 13, 2019 12:02 pm

Thank you Peter. Leaving useful information like this is always helpful.

I'm reasonably content using the SCART-HDMI converter to plug my QL into a TV or monitor with HDMI connection, but it's a clumsy setup with too much cable.

I've long thought that a more permanent solution for QL video is needed, allowing connection to modern monitors. After all, the first question asked by new users (apart from broken keyboard membranes) is usually how to connect the QL to a monitor.

Essentially, some kind of QL-VGA or QL-HDMI converter on a lead or compact plug in box. Something which doesn't need hardware mods to a QL yet doesn't take too much desk space.

A perfect project for our hardware developers such as Vitaly, Dave and Peter I'd have thought!


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Peter
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Re: Optimal Flatscreen monitors for QL and Q68

Postby Peter » Sat Apr 13, 2019 12:55 pm

dilwyn wrote:I'm reasonably content using the SCART-HDMI converter to plug my QL into a TV or monitor with HDMI connection, but it's a clumsy setup with too much cable.

Yes Dilwyn it is far from ideal. But for the other monitors I tried before, not even that SCART-HDMI converter worked. I was left with the GBS8220 which is even larger, has no decent case, and low picture quality. So for me, it was already progress to get QL-SCART-HDMI on the same monitor as the Q68.

The monitor I tested comes with nuts and bolts meant for a wall bracket. The SCART-HDMI converter can be mounted there, which looks quite nice.

dilwyn wrote:I've long thought that a more permanent solution for QL video is needed, allowing connection to modern monitors.

Yes I have also been considering this for ages, but with no satisfying conclusion.

dilwyn wrote:A perfect project for our hardware developers such as Vitaly, Dave and Peter I'd have thought!

The problem is the high complexity of development. A SGC successor with integrated VGA would be roughly the same work for me.

Would the latter provide the solution you see needed, or is it mandatory to support the original 68008 and (S)GC?


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Re: Optimal Flatscreen monitors for QL and Q68

Postby lcww1 » Sat Apr 13, 2019 1:26 pm

Peter - that's a really helpful summary of the ideal monitor setup for QLs, and I'm very interested to hear of your good experience with the Eyoyo EM15A.

I bought an Eyoyo EM15A a little while ago, mainly to use with an Apple ][, as it has composite input. However, I have to say that I've been disappointed with the EM15A - I find that there's a lot of what I will call shine-through from the backlight, meaning that a black screen isn't very black, and no amount of fiddling with the settings seems to be able to improve that. With my QLs, I found that the Chinese black-box start to HDMI converter that I have doesn't yield a complete picture on the EM15A. In addition, I've found that the EM15A doesn't work with the OSSC - the picture flashes on and off continuously. At the moment, I use my QLs with the OSSC and a Dell UltraSharp U2713HM 27" monitor, which looks nice, but isn't quite what we're after here.

I've also got a BenQ BL912 - I use this with various Acorn RISC OS machines, and I had high hopes for this with the QL and OSSC. This is a 19" 1280x1024 5:4 aspect ratio monitor, with VGA and DVI input. Alas, I've not been able to get the BenQ BL912 to work with the OSSC, but it works really nicely, and looks fabulous, with the Q68!

Regarding QL RGB to HDMI - I think it will be worth looking at Hoglet's raspberry pi zero/CPLD based converter described on the stardot forum - see the very extensive development thread here https://stardot.org.uk/forums/viewtopic.php?f=3&t=14430 and also here https://stardot.org.uk/forums/viewtopic.php?f=44&t=16907 - I'm sure this device could be tweaked for use with the QL.


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Re: Optimal Flatscreen monitors for QL and Q68

Postby Peter » Sat Apr 13, 2019 2:32 pm

lcww1 wrote:However, I have to say that I've been disappointed with the EM15A - I find that there's a lot of what I will call shine-through from the backlight, meaning that a black screen isn't very black, and no amount of fiddling with the settings seems to be able to improve that.

With the Q68, contrast 50 / brightness 40 was okay for me. I didn't work in dark surroundings though.

lcww1 wrote:With my QLs, I found that the Chinese black-box start to HDMI converter that I have doesn't yield a complete picture on the EM15A.

That surprises me, as I also just use a cheap Chinese one, not the QL-modded version. Thank you very much for reporting.

lcww1 wrote:Alas, I've not been able to get the BenQ BL912 to work with the OSSC, but it works really nicely, and looks fabulous, with the Q68!

But it has 1280x1024 native, I can not imagine that interpolation blur looks as good as native 1024x768 for the Q68.
Especially vertical interpolation from 768 to 1024 for highres seems far from ideal.

lcww1 wrote:Regarding QL RGB to HDMI - I think it will be worth looking at Hoglet's raspberry pi zero/CPLD based converter described on the stardot forum

I can not see that would help Dilwyn's problems with clumsy setup and too much cable - it seems the same. Or even worse since it has no case. :(


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Re: Optimal Flatscreen monitors for QL and Q68

Postby lcww1 » Sat Apr 13, 2019 4:18 pm

Here's a screenshot from my freshly booted Q68 connected to the Benq BL912:

IMG_0186.JPG
Q68 to Benq BL912


this looks good to me, and the other disp_modes also display well on this monitor.

For comparison, here's the Q68 on the EM15A, set to contrast 50 and brightness 40:

IMG_0187.JPG
Q68 on EM15A


not bad, but the backlight shine-through (seen in window #0) does spoil things for me.

As for Hoglet's RGB to HDMI adapter - do take a good look at what has been achieved with this platform. The second link in my previous post shows a tidy boxed version for the Acorn Atom that is probably much closer to the kind of solution that I imagine most people would like. As things stand, of course this adapter isn't any kind of finished product, but it could be adapted for use with a QL, and would probably be a better and cheaper solution than anything else currently available. I have a bare PCB for this adapter that I've not had a chance to build up yet - if I ever find the time to get it built, then I'll certainly start investigating its use with the QL.


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Re: Optimal Flatscreen monitors for QL and Q68

Postby Derek_Stewart » Sat Apr 13, 2019 4:50 pm

Hi,

Nice picturesof the Q68, but the clock is not set to the correct date.

You need to set the date with the SDATE command and then execute the Q68 Set RTC programme:

EX "win1_q68_q68setrtc"

This will set the Q68 Runtime Clock.

I mainly use an HP LE1901w monitor on the Q68, which has native resoution of 1400x900, bu tge Q68 looks okay in DISP_MODE 4 (1024×768 4 Colours).


Regards,

Derek
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Re: Optimal Flatscreen monitors for QL and Q68

Postby Dave » Sat Apr 13, 2019 5:31 pm

This is only a problem because we have retained compatibility with the old modes. If we abandoned the old PAL and NTSC modes and only used new modes, we'd have far better choices. Unfortunately, it would break so much software - especially games - to abandon modes 4 and 8.

Most business and utility software would be largely unaffected, though.

I have been looking at a fair candidate replacement video system, but it has some snags. On the upside it does produce VESA compliant timing, and would give ultimate flexibility over display outputs in the exact same way the mode definition files on the Risc PC worked. It would also support multiple displays, if a little reword was done to SMSQ/E.

Unfortunately, it would have a hard time supporting mode 4 and 8 pixel bit formats without hardware intervention.

To me, monitor choice is REALLY important, since it's 99.999% of the computer's communication with you.


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Re: Optimal Flatscreen monitors for QL and Q68

Postby Peter » Sat Apr 13, 2019 5:51 pm

lcww1 wrote:Here's a screenshot from my freshly booted Q68 connected to the Benq BL912:

In that low resolution, the Q68 video controller enlarges every pixel to 2x3=6 pixels, so of course it looks good at first glance.
But if you look closer, you notice that the width of pixels is not constant (showing a 8x8 matrix):
BL912_8x8.JPG
BL912_8x8.JPG (5.92 KiB) Viewed 774 times

While is is constant with the EM15A:
EM15A_8x8.JPG
EM15A_8x8.JPG (8.12 KiB) Viewed 774 times

If you use 1024x768, the height of BL912 pixels will also no longer be constant, or badly blurred, this is just hidden by the fact that 256 scales well to 1024, while 768 does not. So a real test would be if you look at 1024x768.

lcww1 wrote:not bad, but the backlight shine-through (seen in window #0) does spoil things for me.

This is strange, I see no such effect here:
Q68_EM15A.jpg

Maybe your EM15A monitor is defective, or there is a large variation in quality. Mine seems to be made in 10/2018.

lcww1 wrote:As things stand, of course this adapter isn't any kind of finished product, but it could be adapted for use with a QL, and would probably be a better and cheaper solution than anything else currently available.

My finished SCART-HDMI converter costs €20 in a decent metal case including power supply. You would need to add the Raspberry, the PLD board, the base board, a case, the costs for front/back panels with connector openings or printed equvalents, the cost for soldering, the costs for a power supply. I see no way to get even close.

The amount of development work would be large, while Dilwyn's mentioned issues would be no better than the existing SCART-HDMI.


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Re: Optimal Flatscreen monitors for QL and Q68

Postby lcww1 » Sat Apr 13, 2019 6:26 pm

Well, to my (admittedly rather imperfect) eyes, the BL912 looks good with the Q68 in all modes - I certainly struggle to perceive any significant blurring at all, in normal use. Perhaps my EM15A backlight is defective - it's certainly somewhat annoying, and to that extent I prefer to use the BL912. I'm interested to see that your EM15A backlight seems much less intrusive.

Regarding SCART to HDMI converters - the cheap Chinese units seem to me to be a lottery - there's no guarantee that any particular unit will work well a QL, at least so far as I can see. I'm pretty sure that my Chinese unit will look identical to yours on the outside, yet mine has been of no use to me at all with my QLs, though it works really well with a BBC Micro. The advantage of the Hoglet project perhaps isn't cost - rather, it's an open source project, that isn't going to suddenly vanish or change spec, or otherwise become suddenly unavailable. The amount of work needed to get it working with the QL is, I think, most unlikely to be large, given the amount of work already done for other relatively similar systems.



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