November 21, 2019, 07:41:51 pm

News:

Have you visited the Allwinner Chipset wiki? - http://linux-sunxi.org/


[Cubietruck] Noise in screen using VGA D-SUB cable and no HDMI output

Started by vilson.farias, January 27, 2014, 05:23:33 am

Previous topic - Next topic

vilson.farias

Greetings,

  my cubietruck is showing a lot of noise in screen (VGA output) since the first boot. When I move mouse I can see some parts of screen show a significant amount noise, not only in the area the mouse is moving.

  The power supply comes from USB  attched to my Lenovo i5 notebook. The only other things attached to cubieboard is a Samsung 22" LED monitor (using VGA D-Sub cable) and a Logitech wireless keyboard/mouse. I'm sure they are perfect because I've been using them from more than a year and I haven't seen any noise.

  By the way, the image quality using D-SUB is not good at all. The screen is whitish and colors are not great. I'm not sure this is a issue yet because maybe I can use some calibration software later. But again, if you have some tips about I would be gratefull.

  I noticed my cubietruck only works on D-SUB. If I connect HDMI cablle and boot it, the "monkey" symbols is shown at first seconds but then nothing else is shown and the screen keeps black no matter how long I wait. I talked to a friend and he told me his cubietruck boots on HDMI without any problems.

  What should you recommend? Should I send the board back to dealer and request a new one? I was wondering I should ask people before doing more tests in order to prevent some bigger problem.

Regards,
Vilson

con

Noise on the dsub link is caused by the wifi signal. You can disable it and check if it is still there. The other problems i'm not sure about. If you connect the CT with a 1A power supply (usually newer phone chargers) the power supply shoudn't be a problem.

vilson.farias

Thanks for your tip about wifi. I gonna test it as soon as possible. I brought the board to work and I'll try in a different monitor/cables/power supply. Let's see if I can have better luck at this time.

Meanwhile, I would know if anybody else has problems with HDMI output. I must remember I can see the little monkey logo at boot time, but a second later the screens turns black and never came back.

Regards,
Vilson

ahrovan

you can change screen 0 and 1 output for check your problem - I use this way for CB1 & CB2 for vga output,Since the CB don't have any vga Circuitry Board -

vilson.farias

Quote from: ahrovan on January 27, 2014, 12:22:31 pm
you can change screen 0 and 1 output for check your problem - I use this way for CB1 & CB2 for vga output,Since the CB don't have any vga Circuitry Board -


It sounds promising. Could you please give some more information about how to set it?

ahrovan

http://brg.vvs.ir/2014/02/cubieboard-vgaboard/


this page just for vga output,but I suggest for you test cvbs (output for tv) - without Circuit and very easy - if you can not find info about that - I will upload for you

vilson.farias

Quote from: ahrovan on January 27, 2014, 03:23:06 pm
http://brg.vvs.ir/2014/01/cubieboard-vgaboard/


this page just for vga output,but I suggest for you test cvbs (output for tv) - without Circuit and very easy - if you can not find info about that - I will upload for you


Thanks for the tip. I'm gonna test it ASAP. HDMI is still an issue to be fixed.

The noise was caused by wireless keyboard+mouse and wifi. After I used a corded mouse and wired lan the noise completly disapeared.

Thanks for the help so far.

vilson.farias

I just flashed my CT to newest Android release (I have a rev. B AllWinner) and tryied the HDMI output again. No luck on my Samsung monitor, still no HDMI but VGA is ok. BUT on my Sony 40" TV the HDMI is working perfect even at 1080p. Well, I still need to understand the whole system a little more before doing deeper tests like ahrovan suggested but so far so good, my CT is not broken  ;D.

con

If the monitor is a 'normal' pc monitor and connected via hdmi->dvi it might give a pink screen or fail on older drivers as the edid info is not read. The TVs generally support all the refresh rates and sizes used by default for the hdmi link.

Don't know if it helps.

vilson.farias

Quote from: con on January 31, 2014, 09:39:57 am
Don't know if it helps.


Yep, it really helps. That's what I thought because my monitor has only DVI connection, therefore I'm indeed using a HDMI->DVI cable.


con

I thought it was mostly fixed in the newer kernels (e.g. patwoods 3.4.43 and up).