Incompatible signal :mad:

[vonz]

Hi there,

I just got this android TV box and trying to match the output signal with my video projector. I am using a HDMI to VGA converter. The TV box detects the projector as being 780p and that is correct. However it seems like a colour channel is dropped somewhere down the line as all the projector is displaying is a yellow/green image. All colour channels seems to be going trough at all other definitions without any problems. I have tested all components and they are all okay. Tv box 780p output signal is well received by my spare LCD monitor, all good there. My laptop sends 780p to projector, all ok.

Now what's going on there, its really bizarre..

Do I have to make a special cable with swapped pins in it? If so which ones? Why is it doing this? Any other way I can fix the problem?

Any insight welcome

Vonz

[jagabo]

Try switching from RGB to YPbPr? Or vice versa.

[vonz]

The option is greyed out.

[lordsmurf]

Those converted never work well.
Converted rarely work well, no matter the input or output.

[vonz]

Lordsmurf: nothing to do with the converter it's doing the job fine read the post correctly please

anyone know what's going on down to the pin level? The red channel obviously comes out from the wrong pin.. I'm going to trace down where it come out and where it has to go, then will make a special cable with crossed wires, i don't see any other workaround

[usually_quiet]

Lordsmurf: nothing to do with the converter it's doing the job fine read the post correctly please

anyone know what's going on down to the pin level? The red channel obviously comes out from the wrong pin.. I'm going to trace down where it come out and where it has to go, then will make a special cable with crossed wires, i don't see any other workaround

The tests you describe in your first post point to the converter as the source of your problem. The Android TV box works fine with your LCD monitor, connected via HDMI. Your laptop works fine with your projector connected via VGA. That certainly makes it look like something is wrong with the HDMI to VGA converter. What HDMI to VGA converter and what Android TV box are you using? A link to the specific devices would be helpful.

[vonz]

Monitor works OK when connected to HDMI to VGA converter. My conclusion is the HDMI converter is doing its job.

[usually_quiet]

Monitor works OK when connected to HDMI to VGA converter. My conclusion is the HDMI converter is doing its job.

The statement "Tv box 780p output signal is well received by my spare LCD monitor, all good there." leaves out the fact that the HDMI to VGA converter was used to connect the TV box to your monitor. There are such things as monitors offering HDMI as a connection.

Also 780p is not a standard video resolution. Did you set the TV box and/or the VGA converter to use 720p (1280x720) output or some other resolution for the test with your spare monitor?

[vonz]

True thing. The signal I am trying to work around is 720p not 780.

The projector automatically recognise the type of signal coming in. When I'm sending the 720p from the TV box it recognises it as such, it is notified in the top right handside in the menu. Missing the red channel but recognises the type.

Now, the converter itself can generate analogue 720p as it shows to work perfectly in VGA input on the LCD monitor. It goes well also upward and downward in the scales.

It looks like the tv box is sending the red channel on the wrong pin at this specific resolution... would that be a possibility?

[usually_quiet]

It looks like the tv box is sending the red channel on the wrong pin at this specific resolution... would that be a possibility?

No. Unlike VGA, HDMI doesn't have dedicated pins for red, green and blue.

...and asked for a link to the HDMI to VGA converter for a reason. I wanted to take a look at the specs to find out what input and output resolutions it supports (among other things), and see if others were reporting any issues similar to yours.

[vonz]

Sorry doing 3 things at the same time, here it is:

http://www.ebay.com.au/itm/120951330116?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

Sorting out a Cat5 issue right now, and will try the component output to see if I get something out of that.

[vonz]

After testing again it appears that all resolutions above 480 are dropping the red colour... All good on LCD monitor.

Now I could buy another HDMI to VGA converter but I got a feeling that it will be exactly the same problem..

Things are pointing toward the projector doing funny things above 480... it's a Mistsubishi XD206U

Now when I get in control of the projector from my laptop it recognizes the brand model as a XD206 (no idea how it can be identified that precisely through vga but anyway) here are the available resolutions for this particular display device:

Values from Windows7 Corresponding recognized resolution on projector (displayed in the menu box)
800x600 > XGA60
1024x768 (recommended) > XGA60
1152x864 > SXGA75
1280x720 (hidden) > SXGA60
1280x960 > SXGA60
1280x1024 > SXGA60

I have tried them all and the projector does it all just fine. Now here are the options on this Android 4.02 TV box within the settings/ display menu:

Android Menu Proj Display Screen reaction
480i > 480i blank
480p > VGA60 all good but harsh pixels
576i > 576i freak out
576p > SVGA50 all good but harsh pixels
720p 60hz > SXGA60 can hear projector pitching up on switch - image nice and smooth but just yellow/green
1080i 60hz > UXGA60 image nice and smooth but just yellow/green
1080p 60hz > UXGA60 image nice and smooth but just yellow/green
720p 50hz > SXGA50 image nice and smooth but just yellow/green
1080i 50hz > UXGA50 image nice and smooth but just yellow/green
1080p 50hz > UXGA50 all good smooth all colours

I finally got a decent image on 1080p 50Hz only. I am pretty sure it was unsuccessful when I tried last time.

Thats not the way its suppose to work is it..

[usually_quiet]

After testing again it appears that all resolutions above 480 are dropping the red colour... All good on LCD monitor.

Now I could buy another HDMI to VGA converter but I got a feeling that it will be exactly the same problem..

Things are pointing toward the projector doing funny things above 480... it's a Mistsubishi XD206U

Now when I get in control of the projector from my laptop it recognizes the brand model as a XD206 (no idea how it can be identified that precisely through vga but anyway) here are the available resolutions for this particular display device:

Values from Windows7 Corresponding recognized resolution on projector (displayed in the menu box)
800x600 > XGA60
1024x768 (recommended) > XGA60
1152x864 > SXGA75
1280x720 (hidden) > SXGA60
1280x960 > SXGA60
1280x1024 > SXGA60

I have tried them all and the projector does it all just fine. Now here are the options on this Android 4.02 TV box within the settings/ display menu:

Android Menu Proj Display Screen reaction
480i > 480i blank
480p > VGA60 all good but harsh pixels
576i > 576i freak out
576p > SVGA50 all good but harsh pixels
720p 60hz > SXGA60 can hear projector pitching up on switch - image nice and smooth but just yellow/green
1080i 60hz > UXGA60 image nice and smooth but just yellow/green
1080p 60hz > UXGA60 image nice and smooth but just yellow/green
720p 50hz > SXGA50 image nice and smooth but just yellow/green
1080i 50hz > UXGA50 image nice and smooth but just yellow/green
1080p 50hz > UXGA50 all good smooth all colours

I finally got a decent image on 1080p 50Hz only. I am pretty sure it was unsuccessful when I tried last time.

Thats not the way its suppose to work is it..

Both the android TV box and the projector are only able to communicate with ("see") the HDMI to VGA converter. The android TV box and the projector can't communicate with each other because HDMI is digital and VGA is analog.

I'd want better results too, but it looks like self-powered converters like yours are very limited. The specs posted on ebay for your HDMI to VGA converter only mention 720p / 1080i / 1080p resolutions specifically, so it may not support other resolutions, and I am not sure if those figures are for input resolutions only, or both input and output resolutions. Since the specs for your converter are sketchy, I looked at some other similar devices. Self-powered converters don't often support HDMI input resolutions below 720p. Some only supported 1920x1200, 1920x1080 (1080p), and 1600x1200 at 60Hz for input and output. Some HDMI to VGA converters powered via USB or a wall plug supported more input and output resolutions than self-powered models, but they cost more. Perhaps the signal from the TV box is not sufficient to power the converter at times.

Your projector's manual says "Set COMPUTER INPUT in the SIGNAL menu to RGB when inputting the HDTV signal as RGB signal." I guess you already tried that.

[Edit]Also some reviews for HDMI to VGA converters (these particular models were not self-powered) mentioned a green-tinted picture (or red, or purple or magenta), so color issues are not unheard of when using HDMI to VGA converters.

This is one of the models where some users reported color problems. http://www.amazon.com/Cable-Matters-Active-Adapter-Charging/dp/B008O7RH5C/ref=pd_cp_e_3

Read the "Compatibility" section on the page above to see what things can cause these types of adapters to malfunction.