brisk
Posts: 28
Joined: Tue Sep 11, 2012 11:18 am

TV flicking - under power issue? same on xbian and raspbmc

Sat Sep 15, 2012 7:35 pm

OK, installed xbian 0.6.3, connected pi to my Samsung 55" LED TV, it cause flicking video on my TV. Didn't play any video file, just the interface is flicking. It is ok on my monitor.

When it flicks, it seems the HDMI signal is gone, my TV outputs: check signal... then after 1 second, it comes back, then goes away... then check signal then comes back...

Could be under powered raspberry pi? Tried 3 USB adapter (Samsung android charger, claimed to output 1A, and other two generic charger both claimed to output 1A), same thing.

Then installed Raspbmc, same problem with these power adapters.

Anyone experienced the same problem? is my TV or the power adapter?

thanks

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johnbeetem
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Joined: Mon Oct 17, 2011 11:18 pm
Location: The Mountains
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Re: TV flicking - under power issue? same on xbian and raspb

Sat Sep 15, 2012 8:26 pm

I have seen behavior like this on my DVI-D monitor connected through an "HDMI Switcher" when my RasPi's 5V0 voltage drops below 4.65V. Switching to different charger may not make a difference, since your voltage drop could be in your Micro USB cable and/or polyfuse F3. It's best to check TP1-TP2 with a voltmeter to make sure it's between 4.75V and 5.25V.

You may be able to fix the problem by increasing "config_hdmi_boost" in config.txt: see http://elinux.org/R-Pi_Troubleshooting# ... VI_monitor.

Dilligaf
Posts: 283
Joined: Wed May 23, 2012 6:48 pm

Re: TV flicking - under power issue? same on xbian and raspb

Sat Sep 15, 2012 11:53 pm

Add the following lines to config.txt:

hdmi_force_hotplug=1
config_hdmi_boost=4


force hotplug forces hdmi output regardless of what is sensed by the Pi, this also allows the Pi to boot with the TV turned off or to another input.
hdmi boost increases hdmi signal output it can be set from 1-7, I find 4 works good with my Samsung

brisk
Posts: 28
Joined: Tue Sep 11, 2012 11:18 am

Re: TV flicking - under power issue? same on xbian and raspb

Sun Sep 16, 2012 1:25 am

Thanks for the suggestions. Unfortunately, problem still exists.

this is my config.txt:

arm_freq=840
core_freq=375
disable_overscan=0

hdmi_force_hotplug=1
config_hdmi_boost=4
overscan_left=20
overscan_right=20
overscan_top=20
overscan_bottom=20


After I changed it, I rebooted it... same thing.
I am using a Samsung U2 USB cable. I am going to change to a different cable.

BTW, it seems it is ok if I don't use network, However the problem starts.while I am using network (e.g. youtube,)

BTW, youtube is not working. I can see categories but never ever to be able to place any youtube video, error is could not find video url.

thanks

brisk
Posts: 28
Joined: Tue Sep 11, 2012 11:18 am

Re: TV flicking - under power issue? same on xbian and raspb

Sun Sep 16, 2012 1:38 am

using a different after market USB cable same thing.

Switched to ipad charger (supposed to output 2.1A) still the same problem....

Now trying to boost to 7...

brisk
Posts: 28
Joined: Tue Sep 11, 2012 11:18 am

Re: TV flicking - under power issue? same on xbian and raspb

Sun Sep 16, 2012 1:40 am

Same problem, even boosted to 7:

config_hdmi_boost=4

Still no go....

Dilligaf
Posts: 283
Joined: Wed May 23, 2012 6:48 pm

Re: TV flicking - under power issue? same on xbian and raspb

Sun Sep 16, 2012 2:45 am

Have you checked voltage from TP1 to TP2? Tried a different hdmi cable? try plugging into the hdmi port on the tv marked PC/DVI?

brisk
Posts: 28
Joined: Tue Sep 11, 2012 11:18 am

Re: TV flicking - under power issue? same on xbian and raspb

Sun Sep 16, 2012 3:10 am

The voltage between TP1 and TP2 is 4.4v, so I guess I am having power problem.

Removed network cable, same result.
Tried an old PC switching power, still 4.4v between TP1 and TP2. However the voltage on switching power side (Red and black) is 5.04v, so somehow there is a drop of 0.64v.

is there a schematic available? TP2 is ground. I guess TP1 is right after the voltage regular?
Next is to remove HDMI cable...

brisk
Posts: 28
Joined: Tue Sep 11, 2012 11:18 am

Re: TV flicking - under power issue? same on xbian and raspb

Sun Sep 16, 2012 4:38 am

Changed to HDMI 1 which was supposed for PC connection, same thing,
tried a different SD card, same thing.
I only have two micro USB cables, one from Samsung phone and one generic, same thing for both...
the voltage is just 4.4v sometimes it drops to 4.2v.
Also, not sure what happened, now my xbian won't get ip address.
I cannot think of anything else to try..

My tv issamsung un55d600, sd card is a Transcend 8GB Class 10 SDHC Flash Card (TS8GSDHC10)

goci
Posts: 12
Joined: Thu May 16, 2013 8:22 pm

Re: TV flicking - under power issue? same on xbian and raspb

Sat Feb 15, 2014 2:31 pm

You may want to try the following:

sudo apt-get install fbset
fbset
fbset -accel true
fbset

cd /opt/vc/bin
./tvservice -s
./tvservice --explicit="CEA 32"
./tvservice -s

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