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vnc viewer shows a small screen

Posted: Mon Oct 03, 2016 9:46 pm
by Fght
see attachment.

i would glad for a solution.


https://postimg.org/image/4dsrejq4l/

Re: vnc viewer shows a small screen

Posted: Tue Oct 04, 2016 11:26 am
by lmarmisa
If your RPi is not connected to any TV or monitor, try this solution:

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sudo /boot/config.txt /boot/config.txt.bak
sudo nano /boot/config.txt
Then modify these lines:

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...
# uncomment if hdmi display is not detected and composite is being output
hdmi_force_hotplug=1

# uncomment to force a specific HDMI mode (this will force VGA)
hdmi_group=2
hdmi_mode=16
...
The new resolution will be 1024x768.

Re: vnc viewer shows a small screen

Posted: Tue Oct 04, 2016 1:05 pm
by Fght
i afraid to do these changes because i don't know how to backup in case of a failure.

i was thinking it is much more simple.

i don't know why this happens

Re: vnc viewer shows a small screen

Posted: Tue Oct 04, 2016 1:48 pm
by jahboater
Fght wrote:i afraid to do these changes because i don't know how to backup in case of a failure.

i was thinking it is much more simple.

i don't know why this happens
You need to learn a little, just a little, which is what the Pi is about.

If you don't have a HDMI monitor plugged in, the Pi cannot ask the monitor what sized screen it is. Instead you need to give the Pi the HDMI details in the config.txt file.

Use the "cd" command to move to the boot directory:

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cd /boot
Then make your backup with the "cp" command:

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sudo cp config.txt config.txt.save
Then if you screw up, you can return the file to its old state with the same cp command in reverse.

Then edit the file with nano as described above.

The last line

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hdmi_mode=58
sets the screen size and the refresh rate. I use 58, you will get scroll bars if its too large. See the documentation
https://www.raspberrypi.org/documentati ... fig-txt.md
See the table a long way down starting with "These values are valid if hdmi_group=2 (DMT):" Choose a value from that table for the mode.

Re: vnc viewer shows a small screen

Posted: Tue Oct 04, 2016 2:01 pm
by FTrevorGowen
Fght wrote:i afraid to do these changes because i don't know how to backup in case of a failure.
i was thinking it is much more simple.
i don't know why this happens
It happens because
1) Without any HDMI connection the Pi defaults to composite video (RCA) mode ie. SDTV resolution/screensize instead of the "larger" HDTV resolution screensize.
2) and the RealVNC server's default mode is to use the "connected" monitor's (or the unconnected default) screensize. (See also @sconemad's comment in this thread: viewtopic.php?f=91&t=161441 )
Trev.

Re: vnc viewer shows a small screen

Posted: Tue Oct 04, 2016 5:14 pm
by davidcoton
Fght wrote:i afraid to do these changes because i don't know how to backup in case of a failure.
Good point. Especially when the post above yours tried to make a backup (to make it easy to undo changes when it went wrong), but there is a typo so there will be no backup. :twisted: :o :shock:

Corrected version (I hope!):
lmarmisa wrote: sudo cp /boot/config.txt /boot/config.txt.bak
sudo nano /boot/config.txt
And to undo any edits:

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sudo cp /boot/config.txt.bak /boot/config.txt

Re: vnc viewer shows a small screen

Posted: Wed Oct 05, 2016 10:09 am
by DougieLawson
Have you looked at the script that starts vncserver. /usr/bin/vncserver is a perl program (plain text script). In there the screen dimensions are defined (can be overriden with a parameter).

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#
# Global variables.  You may want to configure some of these for your site.
#

$geometry = "1024x768";
$depth = 24;
If you've switched to RealVNC you'll need to do your own investigation.

Re: vnc viewer shows a small screen

Posted: Wed Oct 05, 2016 7:12 pm
by Fght
I will try to make the backup as you detailed later on...

I was trying to learn it once but it still made a failure to the system...

I appreciate your effort and hope to tell you that I had succeeded later on..

:-)

Re: vnc viewer shows a small screen

Posted: Wed Oct 05, 2016 7:13 pm
by gideonyuval
I had the same issue, solved following the instructions at http://elinux.org/RPi_VNC_Server, specifically the line vncserver :0 -geometry 1920x1080 -depth 24

Re: vnc viewer shows a small screen

Posted: Wed Oct 05, 2016 10:00 pm
by Fght
So.
I did followed your instruction (for a change).

But I have the same results :)

check it out...

1: the edited file
2: the small vnc
3: i also can't connect to raspbian often. only after rebooting once again. Putty works just fine by the way.

https://s22.postimg.org/ebm430zdd/Capture1.png
https://s22.postimg.org/tyddged5d/Capture3.png
https://s22.postimg.org/gewjaoz69/Capture.png

Re: vnc viewer shows a small screen

Posted: Wed Oct 05, 2016 10:39 pm
by jahboater
Looks like you missed this bit?

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hdmi_force_hotplug=1

Re: vnc viewer shows a small screen

Posted: Thu Oct 06, 2016 12:21 pm
by Fght
I thought this is not mandatory and doesn't required.
let me try:

works nice!


what about 3? (when i get this error once in two tries)
i mean the vnc connection error

Re: vnc viewer shows a small screen

Posted: Thu Oct 06, 2016 12:32 pm
by FTrevorGowen
jahboater wrote:Looks like you missed this bit?

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hdmi_force_hotplug=1
Fght wrote:I thought this is not mandatory and doesn't required.
let me try:
works nice!
...
That setting makes a Pi think that an HDMI cable/device is physically connected. It's sometimes also needed with (older) HDMI-to-VGA converters which fail to provide the (electrical) signal. (AFAIK, most, if not all, HDMI/DVI T.V.'s/Monitors do provide such, but the equivalent VGA signal (via DDC "data") isn't always "passed through" especially some basic VGA switches: https://www.cpmspectrepi.uk/raspberry_p ... tches.html )

Re: vnc viewer shows a small screen

Posted: Thu Oct 06, 2016 8:45 pm
by Fght
im glad that you explained it.


i would appreciate assistant with the other issue also

:)

Re: vnc viewer shows a small screen

Posted: Mon Jul 23, 2018 4:08 pm
by jstars
I found this to be my solution. https://youtu.be/LlXx9yVfQ0k

Again, as above, the solution is a modification to /boot/config.txt