Raspberry Pi Forums

Hallo,

I don't get Lan connection when i don't plugin the HDMI. When i plug in the HDMI my raspberry will works fine (boot and the lan leds turn on), but when i unplug my hdmi and reboot the lan led's don't turn on. How can i fix this?

I too am having some problems with hdmi and network access. Mine is the opposite. When i plug in hdmi then my wifi adapter does not work. I hope someone can help soon.

what ampage is your power adapter

+1 to the amperage question for both individuals

Mine is getting about 2 amps.

It could be also be a grounding issue...the HDMI connector is really the only real ground on the Pi.

JeremyF wrote:It could be also be a grounding issue...the HDMI connector is really the only real ground on the Pi.

Er... no? If that were the case then no pi would ever run without HDMI There have been other grounding issues associated with the HDMI, but no the HDMI is not the only "real" ground on the pi.

tdecurtins wrote:Mine is getting about 2 amps.

Okay, so I'm going to assume that the PSU is plugged into the microUSB power port (and not just being back feed power via a USB port).

I have four follow up questions

1) Do you actually have no network when the LEDs aren't lit up? I know this seems a bit of a silly question, but I know that depending on the revision of the distro the lights can representing different things (though having said that, I can't remember if that applied to the network LEDs or just the SD access and power LEDs) so it's possible you still have network connectivity without the lights
2) Which version of the Pi do you have (512 or 256) and which revision is it?
3) Which distro are you using and when was the last time you updated it?
4) do you loose network as soon as you unplug the HDMI, or only once you reboot without the HDMI connected?

I dont mean to be hijacking this thread sorry to the original poster but i was hoping that my issue would fix yours also.
I cant really tell by the status led what is going on. I have a 256mb board rev. e3912rsv1.
I am using the newest distro just imaged it.
And my problem was the opposite of the original post. When I plug in hdmi then i loose connection. But only on a certain monitor that i have. It tried another monitor and it works fine.
And if you were talking to the original poster sorry about that haha. But thanks for any help!

tdecurtins wrote:I dont mean to be hijacking this thread sorry to the original poster but i was hoping that my issue would fix yours also.
I cant really tell by the status led what is going on. I have a 256mb board rev. e3912rsv1.
I am using the newest distro just imaged it.
And my problem was the opposite of the original post. When I plug in hdmi then i loose connection. But only on a certain monitor that i have. It tried another monitor and it works fine.
And if you were talking to the original poster sorry about that haha. But thanks for any help!

Oh sorry, I got y'all mixed up

I suppose I should ask, if you have the HDMI plugged into the pi prior to booting are you able to use networking or is it a thing where anytime this HDMI device is plugged in it equal no network?

As I was saying above there was a grounding issue with the HDMI (which was actually more of a diode thing) that was resolved with the 512 MB board, and I fear that memory fails me on the details of the issue. Hopefully someone with a better memory than me can chime in, or doing a google search with site:raspberrypi.org and the phrase HDMI short or HDMI one monitor or something along those lines will help you hit the magic thread where people were talking about this.

After some more searching per your suggestions i found this post. :http://www.raspberrypi.org/phpBB3/viewt ... 28&t=18445
But its any time the hdmi is connected to mine that i loose connectivity. While its connected at boot or after.

I'm loath to think the issue could be anything with your PSU as it's 2A and it only happens with the one monitor, but that does assume it's putting out what it claims to put out. so go ahead and break out those test leads on your multimeter and check the voltage between TP1 and TP2 with that HDMI monitor plugged in. It is a straight HDMI monitor right? No HDMI->DVI cable or HDMI->VGA cable in the middle?

My meter was running low on the 9v battery and i dont have anymore but i did get 5v i couldnt really get the amps though it kept saying .001 amps i dont think that is right . But i am using a hdmi to dvi adapter which worked with the other monitors.

I had the same issue with lan not working when HDMI is not connected.
I solved the problem by adding (uncommenting) the following line in the config.txt file;

hdmi_force_hotplug=1

as suggested here; https://github.com/raspberrypi/firmware/issues/54