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O2 Desktop - fuzzy greyness to crisp whiteness - Printable Version

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O2 Desktop - fuzzy greyness to crisp whiteness - defaultrouteuk - 07-21-2020

Dear Experts,

I have an O2 here and am running it with the following cabling: O2 <-> VGA <-> HDMI SCALER <-> HDMI (ASUS MX34V)

I have tried a direct VGA into a 24" Viewsonic LCD with the same results. For the screenshot I took here I connected the SCALER into an Elgato CamLink USB adaptor. In all cases the outcome is the same, the O2 desktop shows with bands of greyed out colors and fuzzy resolution followed by a clear and crisp band in the middle of the screen. I've tried 640x480, 800x600, 1024x768 and 1280x1024 plus a couple of other resolutions made using custom vfo files I made and also some I downloaded.

I did ask my local Oracle (@mapesdhs) and he has suggested that the analogue VGA is most likely the issue and I'm not disputing this I am just wondering if the community has seen similar issues and created any sort of workout or mitigation for something that gives me eye strain! I hope you can see the difference on the terminal. When I load of applications it's not obvious, it just looks washed out.

   

What do you reckon?

RE: O2 Desktop - fuzzy greyness to crisp whiteness - drmadison - 07-21-2020

Definitely looks like standard VGA drama. Most VGA monitors used to have h.phase and v.phase settings you could tweak that would "shift" where that fuzziness was on the screen or hopefully eliminate it. Not sure if the HDMI scaler has anything to help you adjust the settings on it. Typically it's more of an issue at higher resolution - have you tried direct on VGA at lower resolutions and also seeing it there? What model HDMI scaler are you using?

In the end, it's the reason I've gone all digital with my displays even on my SGIs (1600sw on O2, and DCD->1920x1200 LCD over DVI on the Octane2). Obviously that's not an option for everyone.

RE: O2 Desktop - fuzzy greyness to crisp whiteness - weblacky - 07-22-2020

Well, the picture you provide clearly looks like the image is being altered after the fact (font kerning seems wrong for that aspect). For the "Areas", what VGA cable are you using? Kind of reminds me of interference (like ghosting) due to poor shielding. Does this scaler just plug right into the VGA port, or is there a separate Cable? I would try a MUCH thicker VGA cable (if possible). Since you mentioned both a monitor and a scaler, I assume you reused the VGA cable...so I'd start there. Back in the 90's VGA cables were the side of pythons and never thrown out. If you used one of those blue colored DELL VGA cables you get from computer recyclers...maybe try something heavier and don't run it close to other equipment, in case of bad EMI.

I'll discount the scaler, give you said it happens on a direct attachment to a monitor as well. Also, grounding loops can cause stuff like this too, but that's a different issue.

RE: O2 Desktop - fuzzy greyness to crisp whiteness - defaultrouteuk - 07-22-2020

Hi All - actually I really appreciate the feedback. The VGA cable is rather 'pythonic' with decent impedance and shielding. I am running it alongside other cables but I have tried not to without any noticeable change. Yes I can confirm I see the same issue on VGA<->VGA as well as the VGA<->HDMI, it's got this weird fuzziness. It just messes with my eyes I think I have to blink and it'll go away...doesn't go away.

Regarding the scaler it's a Kramer VP-434: https://k.kramerav.com/downloads/manuals/vp-434.pdf

The scaler is great actually and allows me to run without an SOG adaptor into the ASUS. I have messed around with it a lot (clearly not enough) and used AUTO mostly but here is where @weblacky came to the rescue. There is a FINETUNE feature and I'd largely left at the default settings. I can't give a full report right now because I'm in the office, but when I get home I'll tinker and try to find the sweet spot. Before I left for work I adjusted the PHASE value and it did seem (at least to my morning eyesight) to make things a little clearer.

TLDR; I have found a feature on the scaler that may make the image better. I'll update when I get home later.

RE: O2 Desktop - fuzzy greyness to crisp whiteness - defaultrouteuk - 07-22-2020

Hi All,

In case anyone is interested I'll push up my findings but honestly I didn't get a total closure. I figure it's as good as I can get it after much messing around,  an expert may get a better result. The main thing I tried differently was setting 'AUTO TUNE' under the FINETUNE menu option. This seems to scan the input signal and do some funky stuff. When I start it the first time it looks like waves of pulsing grey/white until it settles down. The H and V sync options just centered the image on the screen and did nothing to the actual clarity.

I did also set manual options earlier in testing which worked the same (as the auto) but I figured AUTO TUNE means whatever I might put in should work the same. For anyone who is interested the actual options are arbitrary and don't seem to correlate with any hard numbers I've found related to the CRM output from the O2. I also tried a couple of custom resolutions (https://github.com/ccg/irix-video-modes) but by far the tightest and cleanest seems to be 1280x1024_75Hz. None to the other frequency options gave a good result, they were all washed out or hazy, even the 60Hz which was interesting.

LOGIN SCREEN
=========
   

winterm and xsetmon
============
   

KRAMER SCALER MAIN MENU (note 1080P60)
===========================
   

KRAMER SCALER FINETUNE OPTION
======================
   

Maybe it'll help anyone out there. 

Specifically I like the idea of this scaler as an option for those of us who have one monitor (or space for one monitor). I got this unit for about a ton (GBP100) off eBay and I don't need to find a sync-on-green compatible monitor. I'm yet to find the relevant technical statement on the scaler to explain or guarantee my findings, but I have tried a bunch of monitors now with this scaler and the output is always fine. This monitor (as I said earlier in the thread) is an ASUS MX34V.

Best of luck and thanks to anyone with the patience to help me out.
Rich