il_diavolo
Posts: 137
Joined: Mon Dec 02, 2013 7:56 pm

RPi 2 - No HDMI signal

Sat Jul 11, 2015 4:49 pm

I have recently bought a RPi 2 to supplement my "old" RPi B rev 2. I have a Noobs SD/micro SD card on which I am developing software for a robot project, all the coding being done on the RPi B. When the RPi 2 was delivered a few weeks I ran it once using a previously configured micro SD from the B, by SSH, and everything worked fine.

Today I swapped all the leads from the "B" to the "2", including the HDMI lead to computer monitor, to see if the Python code which was running rather slowly on the "B" would work better on the "2". I was somewhat dismayed to find that there appears to be no output on the HDMI, the monitor display saying "No signal".

I swapped all the cables and the SD card back to the "B" and everything worked, including the HDMI. I have Googled the problem and most of the solutions found seem to indicate that "configure.txt" needs amending (hdmi_hotplug=1 or something similar). I am reluctant to do this as it is all working on the "B" as it stands. I also made sure that the monitor was ready before booting the "2".

I can still SSH into the "2" proving that everything has booted up correctly. Can anyone suggest any solutions before I send the "2" back to the retailer?

Thanks
Il Diavolo

drgeoff
Posts: 9729
Joined: Wed Jan 25, 2012 6:39 pm

Re: RPi 2 - No HDMI signal

Sat Jul 11, 2015 6:34 pm

Put a fresh download of Raspbian on another card and try RPi2 and HDMI display with it.

MrEngman
Posts: 3841
Joined: Fri Feb 03, 2012 2:17 pm
Location: Southampton, UK

Re: RPi 2 - No HDMI signal

Sat Jul 11, 2015 6:51 pm

Edit the file /boot/config.txt and uncomment the 2nd line

Code: Select all

# uncomment if hdmi display is not detected and composite is being output
#hdmi_force_hotplug=1
This has fixed the problem you are having for others who have moved to the Pi 2B.

MrEngman
Simplicity is a prerequisite for reliability. Edsger W. Dijkstra

Please post ALL technical questions on the forum. Please Do Not send private messages.

il_diavolo
Posts: 137
Joined: Mon Dec 02, 2013 7:56 pm

Re: RPi 2 - No HDMI signal

Sat Jul 11, 2015 7:25 pm

MrEngman, I have tried hdmi_force_hotplug=1 but that did not resolve the problem.

drgeoff, I shall try that, thanks, I've got a couple of unused Noob SDs. If that doesn't work I'm guessing it's a hardware problem.

Il Diavolo

localhost
Posts: 4
Joined: Thu Jul 09, 2015 12:20 am

Re: RPi 2 - No HDMI signal

Sun Jul 12, 2015 3:06 am

I had the No signal issue using my Pi as well with 4 HDMI TV's im thinking it was either a SD issue or a bad install of the Pi OS.

I made a thread about the no signal issue like you have might be something with your SD card im not an expert but if you can place the SD card into your old Pi and you get a signal just fine with that SD card data then it might not be your SD card.

But if you made a clean install on the SD card for the Pi2 then it might be a bad install of the OS unless your using sd card you never used before then it might be a sd card issue.

I put my Rasbian from NOOBs on my 16GB sd card i got from my old droid and it worked fine i have 2 32GB sd cards that don't wanna display a signal i haven't retried mainly because i don't have a HDMI that i can use without having to carry a bunch of stuff with me to it up.

il_diavolo
Posts: 137
Joined: Mon Dec 02, 2013 7:56 pm

Re: RPi 2 - No HDMI signal (resolved - sort of)

Sun Jul 12, 2015 8:55 am

Just had my "New Horizons moment". Approaching Pluto rapidly and not able to see anything!
However, I tried at least 4 known to be working SD cards and 2 fresh Noobs cards and nothing appeared, either on the monitor or the TV. I edited config.txt, "hdmi_safe", "hdmi_force_hotplug" and a couple of others for luck, all to no avail.
I rebooted after each edit and when there was no result I put config.txt back to the working configuration for the "B".
I rebooted with another fresh Noobs card to log in via SSH and suddenly showing on the TV was the scrolling text of a Pi booting! HDMI now working with all my SD cards (those with a micro SD obviously) and with the unedited config.txt files.
I can only assume that I somehow prodded a chip into life but I've no idea how!
Thanks for your help.

Il diavolo

il_diavolo
Posts: 137
Joined: Mon Dec 02, 2013 7:56 pm

RPi 2 - No HDMI signal - Solved and the Unsolved!

Wed Jul 15, 2015 7:59 pm

Just had my "New Horizons moment". Approaching Pluto rapidly and not able to see anything!
However, I tried at least 4 known to be working SD cards and 2 fresh Noobs cards and nothing appeared, either on the monitor or the TV. I edited config.txt, "hdmi_safe", "hdmi_force_hotplug" and a couple of others for luck, all to no avail.
I rebooted after each edit and when there was no result I put config.txt back to the working configuration for the "B".
I rebooted with another fresh Noobs card to log in via SSH and suddenly showing on the TV was the scrolling text of a Pi booting! HDMI now working with all my SD cards (those with a micro SD obviously) and with the unedited config.txt files.

I can only assume that I somehow prodded a chip into life but I've no idea how!
In my previous post I thought I had resolved the issue but it still a problem. I'm now convinced that it is a hardware problem. When I first plug up the RPi 2 from cold there is no HDMI output. If I leave it running, after about 30 minutes the HDMI comes to life. I can then turn the RPi 2 on and off and the HDMI works every time. However, the following day this sequence of behaviour repeats itself. I am guessing that a component needs to warm up a little in order to work.

Unless anybody has any other ideas?

Il Diavolo

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