X28 artifacts/oddities

[Space]

Hi,

Just had an opportunity to install my X28 kit, and I seem to be having a few issues.

In 4K60 mode, I occasionally get a flicker along with a message about "resolution too high" - also, I can get the signal to go out entirely by trying to wiggle the DP cable a bit. The cable previously worked fine (it was the same cable that I used to drive the 4K monitor that I took the panel from) - is this a cable issue or something wrong with the DP2LVDS cards?

Also, the colors on mine seems very, very off - reds get shifted into blues, and blues gets shifted into an amber color. Is this possibly related to the first issue?

Thanks

[ZisWorks]

Having the image drop out when wiggling the cable is a dead giveaway that the cable isnt mating well or is damaged mear the end. Please try another cable. Bizlink 2m cables are around $3 on ebay and work well.

[Space]

Just tried it with a new cable I had lying around - it doesn't drop out when I try to wiggle the cable anymore but it still seems to flicker once in every while and exhibit that strange color shift.

(I've ordered another set of cables though just in case if something's wrong with that cable as well)

[ZisWorks]

Can you upload a picture?

One closeup, one full screen image.

[Space]

Attached. The closeup probably isn't very good - the phone camera didn't focus well this close in. I'll try to get another shot with a different camera when I get back from work.

[Space]

Oh, completely forgot to mention that most of the wallpaper should be blue, and not Amber.

[ZisWorks]

I could understand the whole image being inverted (using 39" panel config on 28" does this), but your windows ui elements are normal. Is there some software doing this maybe? If you use the 1080p mode and enter bios, does it look normal there?

If you use 4k120 mode, does the problem persist across the whole screen?

[Space]

Attached a BIOS screenshot - the BIOS screen is supposed to be mostly blue as well.

[Space]

Yep, issue persists across the entire screen if in dual input mode.

[Space]

So, part of the issue is definitely something I'm plugging into the GPU - if I unplug everything and then only plug in the monitor with the good cable, all flickering stops. It doesn't fix the color issue though.

[Lukas]

Definitely Red-Blue channels are swapped, easy to confirm in image editors.
Well, problem is not in lvds cables atleast, channels are interlaced there

[ZisWorks]

No, not quite. Black is yellowed too. Ive seen this behavior with improperly configured inversion (internal stuff, not user accessible).

Nowhere in the system can color channels be swapped accidentally, so this is a strange issue.

Lets swap your tcon and see if that fixes the issue. Will email directly to set up.

[Space]

So, I still haven't figured out what the issue is - it's definitely not the tcon or the DP2LVDS board, though. I'm going to check with a different GPU just to make sure it's not something strange that my GPU is doing. Past that, I wonder if the panel revision on the LCD monitor that I took the panel off of (it was a Samsung U28E590) is somehow different...

[ZisWorks]

Oh, that could be it. Can you take extremely detailed pics of the original tcon and xr/xl boards? These are the long thin boards along thr bottom edge which connect between the tcon and glass. I need to be able to follow ttraces from the flex connection to the chips driving the panel.

Background for others reading this thread: Op sent back the original tcon which worked in my testing, I sent back a different tcon and the x39 kit (OP ordered one of each), same result with the two new tcons and swapping dp boards between the kits also didnt fix it. It doesnt look like a board failure but rather a compatibility problem.

[Space]

Original tcon images attached (I'll post a link to the XL/XR boards in a bit - my phone doesn't do macro shots well and I had to resort to using my DSLR to shoot them, but they also came out to be around 200MBs total)

[Space]

Link to the XL/XR boards:

https://photos.app.goo.gl/yXhmfHIkBEkTF6fA3

[ZisWorks]

the boards look to be the same as our box of panels. The traces from fles connector to panel driver are clearly connected the same, so ordering to the glass should be the same too.

Can you get an all white(as displayed) image on the screen and take a picture of the upper left corner? This is to check subpixel ordering. Also confirm that the tcon is on the side of the panel closest to the bottom of the image. Maybe there is a panel version that has a different color filter pattern or something. From the pics, it looks the same as what we are using.

[ZisWorks]

Hmm, seems like there is a RevC1 and a RevC2 for M280DGJ in addition to C3.  Just got a RevC1 out of a Dell P2815Qf.  Will poke at it to see what can be done to support this variant.

[Space]

Yep, I was going to say - the only difference is that mine says "Rev C1".

[Robot]

I have a C3

[ZisWorks]

I did some more testing on my C1 and C2 panels.  Previously, testing was done with a damaged tcon, so results were wrong.

C2 and C3 behave the same.

C1 swaps the red and blue channels. 

Haven't fully tested it yet, but C1 panel is now working in my x28.

Unfortunately, the reason why red and blue channels are swapped is because the C1 panel is BGR subpixel ordering instead of RGB.  This will make subpixel font rendering look really bad unless you configure it properly.  If you do configure supbixel font rendering aka cleartype, it will be fine.  Overall a minor issue, but something to be aware of.

Here is a picture of the cursor in the upper left corner.

[Space]

For some reason that image doesn't appear correctly for me - it just appears as a grey error symbol.

Would it just be a firmware update for the tcon once released?

[ZisWorks]

Yes, fw update to swap color channels. I will have the programmer sent to you next. Should be ~1 week

[ondrej]

I'm having the same issue as OP. My red/blue channels are swapped. How can I fix this?

[ZisWorks]

I'll ask that the programmer be sent to you after Space.

Need fpga fw V039 to support M280DGJ-L30 C-1 version.

[ondrej]

Zis, I already have a Xilinx platform cable, so no need to mail me the programmer. Is there a place I can download fw V039?

[Space]

I ended up just getting a programmer as well - figured that I'd probably have a use for it later on. Where would I get the new firmware?

[ZisWorks]

Did the file that I sent work for you?

[Space]

Something rather unexpectedly came up and I haven't had time to flash it yet. I'll probably be able to get to it sometime this or next week.

[Space]

Okay, finally had a chance to properly take apart the thing and flash it (along with the DP2LVDS controller and firmware).

Colors seem fixed. However, for some reason none of the other inputs other than 4K120 seems to work, and 4K120 results in the current screen being duplicated across the two halves of the monitor (as if the computer thinks that they're 2 separate monitors instead of one).

Also, should I not put back the metal backplate that usually goes over the tcon? (I get an overtemperature warning with the backplate)

[ZisWorks]

Flashed both DP chip and DP2LVDS arduino firmwares?

Duplication like that happens when the host doesn't understand tiled displays.  Are you using linux? 

Use the thermal pad from stock tcon, cut the black plastic sheet to allow better contact with pad in new location.

[Space]

Yep, flashed both the DP chip and the arduino firmware. I'm using Windows 10.

[ZisWorks]

We resolved these issues with a videocall.

[ondrej]

Flashed the firmware v039 you sent me. Display shows "v039", but colors are still inverted for me.

[ZisWorks]

In order to use the -C1 variant of M280DGJ, you have to set the "TEST" dipswitch to "ON" while having the "M280DGJ" dipswitch also set to on.  Other switches should be OFF.

[ondrej]

Excellent. That worked. The screen flickers with channels inverted when powering on or changing resolutions. After the initial flicker, the colors are correct. Is this normal behaviour?

[ZisWorks]

Normal. Takes a moment to stabilize the system.

[ondrej]

I'm having problems with power delivery (I'm assuming) to the TCON using the LVDS cables. About half the time the TCON board will not power up, wiggling the LVDS cables and power cycling the whole system resolves the issue most of the time. I've also noticed that sometimes the right side of the panel will display a small jittering lines in different spots. I'm assuming all of these problems are due to a problem with the LVDS cabling. Is there a place I can order replacement, possible higher-quality cables? I tried looking for 41pin FI-RE41HS cables on eBay and AliExpress, but not having much luck. I'll try to photograph/record the line jitter next time it happens.

[ZisWorks]

Have you updated dp2lvds and dp chip firmware? This is likely ehat is causing what you described as the power issue.

For the other stuff, contact directly and we will work it out in a videocall.

[Space]

So, strangely enough, my single input modes just decided to start working one day (fired up the monitor in preparation to mount it properly, decided to try 4k60, and it just came up instead of blacking out). However, now I'm getting an issue where the left 1/4th of the screen is tinged blue (it used to be tinged red but after fiddling with the ribbon cables that connect the tcon to the panel - and figuring out that for some reason the ribbon cables aren't really interchangeable - it's now tinged blue). On a solid black background, that area is completely blue instead (and the right 1/8th of the blue portion seems to partially ghost the other 1/4th of the left half that's not blue). This happens in both single and dual input modes - I wonder if that ribbon cable is somehow broken).

[Space]

Well, nevermind. That seems to have fixed itself as well.

[mikes...@gmail.com]

I know this is a little bit of an older group post, but I just sent Zis an email asking about details on how to get started... then started reading some more. Turns out I have two of the U28E590 panels listed in this thread. What was required to get them running at 1440p 144hz and 1080p 240hz?

Is that possible with this panel?

And, what are we looking at regarding the physical modification to the case to get the required component swap/additions to fit?

Thanks in advance.

[ZisWorks]

Yes, UE590 has a compatible panel, and the majority of 28" panels will oc successfully. Havent dealt with modding the housing though, seemed tight when I had one apart. Might need to hack it apart to be able to fit heatsink and be able to plug in the dp cables.

28" can do 1440px tall at 160-180hz depending on panel oc limit, but mapping is 1:1 so you get a letterboxed effect. Width can be anything, 3840(dual input),2560,1080 are all ok.