GDM-W900 problem with LCD timings [720p & 1080p @60Hz]

[Fudoh]

That definitely works. The question is really if the specific DAC paired with the 301 is honoring the full total width. I would assume that most will, but I wouldn't rule out, that some are re-timing the signal by shortening areas not visible anyway.

[BenoitRen]

I've read this thread with great interest, as I have a GDM-FW900 paired with a HDFury 2 Gamer RGB.

Using a Switch at 720p actually works great for me. Played many hours of Dragon Quest Builders 2 that way. When I started playing The Messenger, I noticed a scaling artifact on moving blocks, so I switched to 1080p. Ever since then, after some time playing (I think about half an hour), my monitor will seem to lose signal for about a second every three to five minutes.

I did notice the distortion brought up by Ryeno (but at 720p), but it's not as severe, and thought it was due to geometry. Good to know that it's probably due to a timing issue.

So... Does this mean I should invest in a OSSC? I briefly looked at the Extron DSC 301 HD, but it's ridiculously expensive.

[orange808]

I've read this thread with great interest, as I have a GDM-FW900 paired with a HDFury 2 Gamer RGB.

Using a Switch at 720p actually works great for me. Played many hours of Dragon Quest Builders 2 that way. When I started playing The Messenger, I noticed a scaling artifact on moving blocks, so I switched to 1080p. Ever since then, after some time playing (I think about half an hour), my monitor will seem to lose signal for about a second every three to five minutes.

I did notice the distortion brought up by Ryeno (but at 720p), but it's not as severe, and thought it was due to geometry. Good to know that it's probably due to a timing issue.

So... Does this mean I should invest in a OSSC? I briefly looked at the Extron DSC 301 HD, but it's ridiculously expensive.

Wait and save money for an OSSC Pro. I understand it will have a processing mode that's similar (in some ways) to a DVDO iScan unit (without the chroma subsampling) using a partical frame buffer. Even if the official firmware doesn't support the timing you need, it will be possible to add it.

[BazookaBen]

Well for the Messenger, I'd recommend the PC version, where you can play at native 640x360p. Get scanlines and all that stuff. Though you'll have to add a bunch of lines to the front and back porch to get the horizontal scan rate to 30kHz.

[M3Patterns]

I got the linuxbot3000 / wakabavideo component to VGA adapter in. I don't currently have the W900 (I'm getting some caps replaced) but I tested it out with my other PC style monitor that does 720p.

When using the adapter in HV mode with a PS3 at 720p over component, it appears to have the same waviness that HDMI has.

However, when using the adapter in composite sync mode, the image looks either perfect or nearly perfect. (It's hard to tell if there is super slight residual waviness at the extreme top edge or if it's just the geometry of the monitor.)

Either way, it is definitely good enough and I can finally play using 720p without the waviness being an issue for me.

Unfortunately 1080i still has the same waviness. When using 720p, the sync on the monitor is still at 44.95khz. I suspect that composite sync with 720p is somehow giving something very close to CRT timings, but not quite all the way.

I can't yet guarantee it would be a fix for the w900, but I'm extremely happy with how it's working on my other monitor.

[luk360]

Hello, i have the same problem, i have two GDM W900, 480p works no problem, 720 has weird issues and 1080p does not show a picture.

The GDM FW 900 works somehow different, you can not compare them.

Any updates for this?

I have a hdfury3 somewhere to try if that helps.

[Frosal]

Hello, i have the same problem, i have two GDM W900, 480p works no problem, 720 has weird issues and 1080p does not show a picture.

The GDM FW 900 works somehow different, you can not compare them.

Any updates for this?

I have a hdfury3 somewhere to try if that helps.

No updates as I've acquired a bunch of other CRTs so mostly been tinkering with them. I haven't tried using DAS to modify the "default" resolutions yet, not sure if that's even possible.

Yeah, the FW uses newer timings, so it doesn't have this problem at all.

[BazookaBen]

Yeah, the FW uses newer timings, so it doesn't have this problem at all.

I'm not sure if "timings" is the right word, because 1080p uses the same timings from the PS3/4/5 no matter what display you hook it up to (CVT reduced timings, basically). That's what I've been told anyway, I haven't analyzed the signal myself

So I'm thinking the W900 just needs more blanking, larger porches, to successfully draw a picture, for whatever reason.

Because I've been playing 1080p games on my Lacie 22 Electron Blue IV for many years now, and it works mostly fine. There is warping on the far right and left, because of the reduced blanking, but I just overscan that part of the picture. Comes out to about 5% overscan total, if I recall correctly.

I actually have some old HD test patterns you can load on a PS3/4 to test geometry/overscan/convergence, if anybody wants them

[luk360]

I tried with Xbox series S with a extron RGB 580xi. 720p does work well with it on the W900 without using any of the switches. So if you have an RGB Interface it may be worth a try. 1080p still doesent work.
I also have a Extron for converting Hdmi to RGB directly somewhere, i will test that next.

[BazookaBen]

Sounds like the Retrotink 4k might be versatile enough to fix 1080p for old monitors and add more horizontal blanking.

Maybe the OSSC Pro and Retrotink 5x too?

I haven't looked too deeply in all the options for signal manipulation these things offer.

[LDigital]

When I had a fw900 I had everything up to ps4 running through a basic ossc. The ossc would correct whatever was wrong and it worked perfectly