abramq
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(solved) B+ displays at most 800x600 (higer res big problem)

Sun Aug 03, 2014 12:23 am

Hello,

Just bought new B+ and...just spent two days trying make it work... Only partial success.
After googling and applying all possible solutions in all possible combinations, all my B+ can display is resolution 800x600 @60Hz. Not any other higher.
I got this by modifying \boot\config.txt file, adding:
hdmi_force_hotplug=1
hdmi_group=2
hdmi_mode=9
config_hdmi_boost=6 (also was using value of 7 - do not want use more as it is described to be dangerous)

Any attempt to increase the resolution leads to:
- interferences on the screen (many many blinkig pixels) or / and
- blinking the screen (normal screen of desktop <-> black screen repetition) or
- completely black ("no signal" info) of my display

As a display I was using my TV LG 42LV5500 and computer monitor iiama ProLite B2209HDSD and an other TV (Samsung - can't remember the symbol now - was at my friend). The result always was the same.
I was also using two different supply (5V, 2A) and two different HDMI cables (one short 0,5m and one 1,5m).

Should I send the B+ back to the shop to replace? Or is it normal? What resolution you get on your TV's?
I will be grateful for any answer,

Best greetings,
Robert

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mahjongg
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Re: B+ displays at most 800x600 (higer res -> big problem)

Sun Aug 03, 2014 1:50 am

The B+ is in no way different in respect to its HDMI output than the B, as its using the exact same SoC, and HDMI logic, and the latter can in no way have any influence on the generated resolutions, so you are simply doing something wrong, or there is a software problem. perhaps you indeed should return your PI, as this isn't normal.

abramq
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Re: B+ displays at most 800x600 (higer res -> big problem)

Sun Aug 03, 2014 9:50 am

Thanks for your answer - would you please tell me what is the higher resolution you can get on your RPi via HDMI?
Thanks in advance!

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DougieLawson
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Re: B+ displays at most 800x600 (higer res -> big problem)

Sun Aug 03, 2014 9:56 am

Having hdmi_safe=1 sets HDMI safe mode. That mode sets the screen dimensions to VGA shape (800 x 600) as that is 100% guaranteed to work on any HDMI screen.

http://elinux.org/R-Pi_Troubleshooting# ... put_at_all
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mahjongg
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Re: B+ displays at most 800x600 (higer res -> big problem)

Sun Aug 03, 2014 10:00 am

abramq wrote:Thanks for your answer - would you please tell me what is the higher resolution you can get on your RPi via HDMI?
Thanks in advance!
From wikipedia.
Supported digital video resolutions are: 640 × 350 EGA; 640 × 480 VGA; 800 × 600 SVGA; 1024 × 768 XGA; 1280×720 720p HDTV; 1280 × 768 WXGA Variant; 1280 × 800 WXGA Variant; 1280 × 1024 SXGA; 1366 × 768 WXGA Variant; 1400 × 1050 SXGA+; 1600 × 1200 UXGA; 1680 × 1050 WXGA+; 1920 × 1080 1080p HDTV; 1920 × 1200 WUXGA.Also to be supported are the generation of 576i and 480i composite video signals for PAL-BGHID, PAL-M, PAL-N, NTSC and NTSC-J

a complete list can be found here:
http://elinux.org/RPiconfig#Video

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DougieLawson
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Re: B+ displays at most 800x600 (higer res -> big problem)

Sun Aug 03, 2014 10:04 am

It's going to be power supply or HDMI cable. These problems are ALWAYS power supply or cable problems.

http://www.argos.co.uk/static/Product/p ... 667576.htm
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Re: B+ displays at most 800x600 (higer res -> big problem)

Sun Aug 03, 2014 12:43 pm

Note to self, don't plug a Pi into a telly.....

Not owning a HDMI telly probably has a lot to do with it. :)

Old school DVI monitor just works at native resolution. (1920 * 1080).
Don't judge Linux by the Pi.......
I must not tread on too many sacred cows......

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FTrevorGowen
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Re: B+ displays at most 800x600 (higer res -> big problem)

Sun Aug 03, 2014 6:50 pm

abramq wrote:Thanks for your answer - would you please tell me what is the higher resolution you can get on your RPi via HDMI?
Thanks in advance!
FWIW, some notes of mine w.r.t "optimised" display settings for a few T.V.'s can be found here:
http://www.cpmspectrepi.webspace.virgin ... DMI_Inputs
Whilst those "tests" were performed some time ago with a "B2" Pi I've no reason to expect any difference were I to use a "B+" (ie. I see no difference between any of my Pi's when using HDMI, albeit usually with a monitor via an HDMI-to-DVI cable).
Trev.
Still running Raspbian Jessie or Stretch on some older Pi's (an A, B1, B2, B+, P2B, 3xP0, P0W, 2xP3A+, P3B+, P3B, B+, A+ and a B2) but Buster on the P4B's. See: https://www.cpmspectrepi.uk/raspberry_pi/raspiidx.htm

abramq
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Re: B+ displays at most 800x600 (higer res -> big problem)

Sun Aug 03, 2014 8:43 pm

DougieLawson wrote:It's going to be power supply or HDMI cable. These problems are ALWAYS power supply or cable problems.
Well, so... I will go for the third new cable and the new suply... As I was wrinting I was trying tw cables - the same I use connnecting my laptop to TV without problems. I was also using two suply - one original from Samsung tablet (5V 2A) and one sold together with that Pi.
There is not worse that problems at the very beginning ;-)

p.s.
I am connecting the Pi to the TV (not PC) because I wanna watch my pictures on big screen.

niwa3836
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Re: B+ displays at most 800x600 (higer res -> big problem)

Mon Aug 04, 2014 12:49 pm

Probably not relevant for your issue (although worth checking), I have found that certainly images / mp4 through omxplayer needed more gpu_mem set in the config.txt file (and reboot). Mines now permanently at gpu_mem=128 and problems have gone away.

wizee
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Re: B+ displays at most 800x600 (higer res -> big problem)

Fri Aug 08, 2014 3:55 am

I'm having the exact same issue and it is definitely new to the Raspberry Pi B+. I have an LG 32LS3450-UA TV to which I hook my Raspberry Pis. I have three original Model B RasPis and they all work perfectly out of the box with any cable in any position and any power supply I have.

On Tuesday, I received a B+. It sort of worked with my TV, but it flickers and glitched a lot out of the box. After a while HDMI just stopped showing anything at all. I tried two different cables and three different power supplies with no luck. Jiggling the cable into certain positions would sometimes make it work, but it was extremely unreliable. I then enabled HDMI safe mode, and found that it worked at low resolutions. Upping the resolution to 800x600 (HDMI group 2, mode 9) still worked, but showed some graphical corruption sometimes and sometimes went out. Upping the HDMI boost level to 6 (from 4) and jiggling the cable more fixed that. At 1024x768 (group 2, mode 16), it also sort-of worked with boost level 6, but the screen occasionally flickered when in GUI mode (x server running).

I tested both my cables and all three of my power supplies with my three older Model Bs, and they all still worked perfectly at full resolution with my TV. I then concluded that I had a defective B+, so I got a replacement today that came under warranty. Same issue happened again!!! Jiggling the cable into a particular position can make it work, but it's unreliable and flickers if the cable shifts even slightly. I'm using high quality cables and good power supplies (iPad chargers).

There is definitely some hardware difference between the B and B+ that causes HDMI issues with LG TVs. The same hardware is rock solid with the model B but nearly unusable with the B+. I don't have any other TVs to test with for now.

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mahjongg
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Re: B+ displays at most 800x600 (higer res -> big problem)

Fri Aug 08, 2014 10:33 am

try to increase HDMI drive level, your monitor might have marginal trouble with the signal strength it receives. There are only very small differences (in the filters) in the Transition-minimized differential signaling lines, (the high speed audio/video connection) all the rest of the TMDS logic (but not the non video logic like CEC handling logic, and 5V output current) has remained the same.

to increase drive strength modify config.txt, form the wiki at http://elinux.org/RPi_config.txt
config_hdmi_boost configure the signal strength of the HDMI interface. Default is 0. Try 4 if you have interference issues with hdmi. 7 is the maximum.
I suggest trying config_hdmi_boost=4

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Re: B+ displays at most 800x600 (higer res -> big problem)

Fri Aug 08, 2014 11:03 am

If "jiggling" the cable changes anything, you have a bad connection (cable, sockets, whatever).
Minimal Kiosk Browser (kweb)
Slim, fast webkit browser with support for audio+video+playlists+youtube+pdf+download
Optional fullscreen kiosk mode and command interface for embedded applications
Includes omxplayerGUI, an X front end for omxplayer

wizee
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Re: B+ displays at most 800x600 (higer res -> big problem)

Sat Aug 09, 2014 2:50 am

I found that bending the cable near the TV-end connector in a particular manner makes the B+ work properly. With the bent cable, I was able to reduce the HDMI boost level down to 4 (I was at config_hdmi_boost=6 yesterday) and I got full resolution working properly. I can now live with the setup. What I don't understand is that the old model B works fine without the bend in the cable (it works fine with the cable in any position dangling anywhere), but the B+ needs the cable bent. Most likely there is some imperfection in my cable or connector at the TV end that the filter circuitry in the model B is fine with, but the B+ is more sensitive to.

abramq
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Re: (solved) B+ displays at most 800x600 (higer res big prob

Sat Aug 09, 2014 10:15 am

This is strange for me - I started this thread and someone else could sign the main thread as "solved" ?!
It is not true, "solved" is completely not about my problem I started here!

p.s.
By the way - my Pi was broken, they gave me new one and everything is ok now, works prefect...

neilf
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Re: (solved) B+ displays at most 800x600 (higer res big prob

Sat Aug 09, 2014 1:01 pm

abramq wrote:This is strange for me - I started this thread and someone else could sign the main thread as "solved" ?!
It is not true, "solved" is completely not about my problem I started here!

p.s.
By the way - my Pi was broken, they gave me new one and everything is ok now, works prefect...
So the problem IS solved then.
FYI, mods have the right to change any thread title so it better reflects the content of the thread.

smnbldwn
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Re: (solved) B+ displays at most 800x600 (higer res big prob

Fri Sep 26, 2014 4:16 pm

I have the same problem with some of my B+ raspberry Pis. I bought a batch of 20 for school use and some worked fine while others default to a low resolution display with a massive raspberry in the middle of the GUI screen (on Raspbian). Same SD cards, same monitors and same HDMI cables. So I guess it must be the Pis. Is this a widespread problem?

russt
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Re: (solved) B+ displays at most 800x600 (higer res big prob

Mon Feb 16, 2015 12:11 am

Just received 2 new of the new pi-2 models from Newark Electronics.

Had this exact problem on one of them. I tried all allowable resolutions both in CEA and DMT mode. Max resolution was limited to 800x600 in DMT mode, and 720x576 in CEA mode.

Guess what? I was using a short 20 inch HDMI cable on the back of the TV, and when I traded it for a 6 foot cable, the HDMI display started working with the higher resolutions.

I've had model B 256M, B 512M, and B+ units hooked up with the short cable, and never experienced this problem before.

I tried with config_hdmi_boost=4 and config_hdmi_boost=7 with no effect. The signal with lower resolutions was very strong, and so I was dubious that this was a problem.

I assume this is some sort of noise problem, and that perhaps the newer models are more sensitive to signal or ground noise.

I've heard about the "flash" problem with the pi-2 models, and since my tv has a bright backlight, I tried protecting it from light, but that also had no effect.

Glad to find this post - especially the bit from DougieLawson "It's going to be power supply or HDMI cable. These problems are ALWAYS power supply or cable problems."

Indeed!

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