ZZ600E3
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Unpowered Raspi breaking HDMI-CEC

Sat Aug 11, 2012 10:44 am

Hi,

I posted in another part of the forum and it's not getting much response so I'm bringing this to the Media Centre section

My other thread was http://www.raspberrypi.org/phpBB3/viewt ... 48#p147548

Basically, whenever an unpowered Raspberry Pi is plugged in to a system with CEC control set up, it completely screws the set up and the devices will no longer communicate properly. And in my experience, only a factory reset of the TV set (which is the main control unit of any CEC set up from what I can see) while the Pi is either unplugged or fully powered up will allow it to detect devices on the HDMI link.

From what I can tell, from the moment it's introduced unpowered in to the loop, the TV is no longer able to send commands down the HDMI channel and I have tested this with it connected via my AV receiver or directly in to one of the TV's HDMI ports. Which ever way it goes round, the TV and a unpowered Pi do not get along.

So far, myself with a Sony Bravia TV set and also another user with a Philips TV set have reported the exact same issues and conclusions as you will be able to see in my linked thread above. I don't know if this is just the odd defective board or certain TV sets flake out under certain scenarios but I'd like for people who use the Pi on a system setup with HDMI-CEC/Bravia Sync or any other name a manufacturer has given it and if they read the linked thread to then give feedback about any issues you may be having.

Even if you do not use the Pi as a media centre, this can still effect you if you plug it in to your TV set since your other devices will no longer be controlled by the TV and auto-off/channel switch etc.

Many Thanks

Chris

dom
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Re: Unpowered Raspi breaking HDMI-CEC

Sat Aug 11, 2012 10:59 am

If you are feeling brave, you can try removing D14. It is ESD protection on the CEC line, and CEC should function fine without it. We think that could be interfering with some CEC devices when the Pi is not powered.

ZZ600E3
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Re: Unpowered Raspi breaking HDMI-CEC

Sat Aug 11, 2012 11:16 am

I take it ESD means Electro-Static Discharge?

Wouldn't that leave my devices open to damage though in the event of a power surge?

Therket
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Re: Unpowered Raspi breaking HDMI-CEC

Sat Aug 11, 2012 11:42 am

Hi there,

I'm the other user having the very same problems with the Philips TV and a Denon AVR.

According to Wikipedia, Pin 14 is not used up to HDMI 1.3c. As the RPi is HDMI 1.3a, removing Pin 14 could be an option, if it helps.
I'll check, if I find a way to disable Pin14 without risking a shortage between other Pins..

Thanks for the advice so far,
Regards
Jens

Mick1152
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Re: Unpowered Raspi breaking HDMI-CEC

Sat Aug 11, 2012 12:31 pm

Interesting, just tonight I left the Pi hooked up to our TV and powered on... when wife went to bed and turned off TV it kept turning it's self back on until I unplugged the Pi's HDMI cable. Guessing this is related??

ZZ600E3
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Re: Unpowered Raspi breaking HDMI-CEC

Sat Aug 11, 2012 12:49 pm

Mick1152 wrote:Interesting, just tonight I left the Pi hooked up to our TV and powered on... when wife went to bed and turned off TV it kept turning it's self back on until I unplugged the Pi's HDMI cable. Guessing this is related??
Always a possibility, what TV is it?

dom
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Re: Unpowered Raspi breaking HDMI-CEC

Sat Aug 11, 2012 1:20 pm

Mick1152 wrote:Interesting, just tonight I left the Pi hooked up to our TV and powered on... when wife went to bed and turned off TV it kept turning it's self back on until I unplugged the Pi's HDMI cable. Guessing this is related??
As far as I understand this issue is only a problem when the Pi is plugged in but powered off.
What was the Pi running? XBMC for example uses CEC and has the ability to power on the TV.

dom
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Re: Unpowered Raspi breaking HDMI-CEC

Sat Aug 11, 2012 1:22 pm

ZZ600E3 wrote:I take it ESD means Electro-Static Discharge?
Wouldn't that leave my devices open to damage though in the event of a power surge?
I think it is static rather than power surges. If you avoid shuffling your feet on thick carpet before touching that specific pin, you'll be okay.
I've had D14 removed for the last month or so, and have had no problems.

Mick1152
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Re: Unpowered Raspi breaking HDMI-CEC

Sat Aug 11, 2012 8:04 pm

dom wrote:
Mick1152 wrote:Interesting, just tonight I left the Pi hooked up to our TV and powered on... when wife went to bed and turned off TV it kept turning it's self back on until I unplugged the Pi's HDMI cable. Guessing this is related??
As far as I understand this issue is only a problem when the Pi is plugged in but powered off.
What was the Pi running? XBMC for example uses CEC and has the ability to power on the TV.
dom,

Thanks for the info, yes, that Pi was running XBMC. My son, (10 years old btw) has one in his room powered on and hooked up to his TV 24/7. He's using as a server for his website coding so no XBMC on that and his isn't doing the same thing. Does appear to be XBMC related, even moved his Pi to the living room TV and can't reproduce it. In summary, forget I said anything, nothing to see here, move along. ;-)

Mick

Therket
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Re: Unpowered Raspi breaking HDMI-CEC

Mon Aug 13, 2012 6:24 pm

I still have no idea, how to disable Pin 14 without risking any damage.
But, I think it is not connected at all. At least, if I look at this hi-res pic: http://elinux.org/File:RPi-Front-JPB.jpg, I cannot see any connection of Pin 14..

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mahjongg
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Re: Unpowered Raspi breaking HDMI-CEC

Mon Aug 13, 2012 6:53 pm

according to the schematics pin 14 of the HDMI connector is unconnected.

dom
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Re: Unpowered Raspi breaking HDMI-CEC

Mon Aug 13, 2012 6:59 pm

Why are we talking about pin 14 of HDMI ?
The surface mount component D14 on rear of board close to the HDMI connector is the component I suggested removing.

Therket
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Re: Unpowered Raspi breaking HDMI-CEC

Mon Aug 13, 2012 7:04 pm

Thanks dom, right at the moment you wrote this, I realized I got something wrong here.
Yes, you've been talking about D14 and I confused this with Pin14.

Looking at the schematics, it absolutely makes sense to try to remove D14.

Thanks
Jens

plexy
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Re: Unpowered Raspi breaking HDMI-CEC

Sun Aug 19, 2012 6:13 pm

Hi ,

having the exact same issue, just wondering did anyone have success with
removing d14 on the pi and if it resolved the issue..
have had to restore the default setting on the tv a few times , the HDMI cable is not the issue asI have tested a few times with both a high speed HDMI cable etc..

Thanks amill

ZZ600E3
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Re: Unpowered Raspi breaking HDMI-CEC

Sun Aug 19, 2012 7:22 pm

Hi Amill,

I've not attempted it myself yet, I am awaiting the delivery of my other unit and the cases before I do anything of the sort.

I've found that leaving the unit on permanently isn't the answer either. It'll be fine for a couple of days and then all of a sudden the CEC link goes down even though the Pi has been on all the while.

I'm hoping this simple mod does fix it but it's not something I'd recommend unless you are confident in doing it and also have a case for the Pi so you don't damage it while handling it there after.

Regards

Chris

plexy
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Re: Unpowered Raspi breaking HDMI-CEC

Mon Aug 20, 2012 7:53 am

Cheers Chris, yeah resetting the TV isn't ideal but I have to say am well impressed
when it is working , being able to power on the pi from the wiselink button on my remote is a god send and the fact I don't need a another remote is a big bonus, here's hoping ..You might keep me posted how you get on ..

Cheers,
D

Therket
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Re: Unpowered Raspi breaking HDMI-CEC

Mon Aug 20, 2012 6:32 pm

Good news!

Removing D14 seems to help. I just removed it 5 Minutes ago and reconnected the RPi to my AV (unpowered). The TV can still start and control the PS3, the AV switched to the right input, great!
Then I powered the RPi up and the TV instantly found the BCM-device, so I think CEC still works on the RPi. But I have no XBMC-image at hand, so I couldn't test CEC control of the RPi.
I will keep you updated.

Regards
Jens

dom
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Re: Unpowered Raspi breaking HDMI-CEC

Mon Aug 20, 2012 6:39 pm

Therket wrote: Removing D14 seems to help. I just removed it 5 Minutes ago and reconnected the RPi to my AV (unpowered). The TV can still start and control the PS3, the AV switched to the right input, great!
Then I powered the RPi up and the TV instantly found the BCM-device, so I think CEC still works on the RPi. But I have no XBMC-image at hand, so I couldn't test CEC control of the RPi.
I will keep you updated.
Thanks for report. I can confirm that for me, with D14 removed CEC is fine (I use it with XBMC all the time).

ZZ600E3
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Re: Unpowered Raspi breaking HDMI-CEC

Mon Aug 20, 2012 7:02 pm

Good news,

Did you just pry it off with a screwdriver or actually de-solder the joints?

I'm going to do it but don't want to mess the board up in the process :)

Therket
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Re: Unpowered Raspi breaking HDMI-CEC

Mon Aug 20, 2012 7:34 pm

I desoldered it with a 0.5mm soldering iron.

@Dom: Do you agree that this is a hardware design bug of the RPi? If so, I think we should add that information to the elinux-wiki. Or do you think this is just a compatibility problem with our other devices?

Regards
Jens

dom
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Re: Unpowered Raspi breaking HDMI-CEC

Mon Aug 20, 2012 7:43 pm

Therket wrote: @Dom: Do you agree that this is a hardware design bug of the RPi? If so, I think we should add that information to the elinux-wiki. Or do you think this is just a compatibility problem with our other devices?
It's a bit like the polyfuses. It's been put there for a reason (ESD protection), but it seems to cause issues with some devices when switched off.
Is it better without it? Still up for debate, but I've had the polyfuses and D14 removed and I don't miss them...

Malard
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Re: Unpowered Raspi breaking HDMI-CEC

Sat Aug 25, 2012 2:07 pm

If you don't want to mess with the Pi itself, we (Pulse-Eight) sell a "CEC-less" HDMI cable, not ideal if you want to use the CEC function when the Pi is on, one other work around is to couple the CEC Adapter and the CEC-less cable, I realise its a somewhat backwards approach and fairly costly!

beninnz
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Re: Unpowered Raspi breaking HDMI-CEC

Tue Aug 28, 2012 5:00 am

Just to add to the above, I've had the exact same problems - I've got 3 pi's and they all create the same issues (irrespective of distro - Arch, Wheezy, raspbmc, Openelec). My set up is as follows;

1. Samsung UA40D6000 tv with CEC ('Anynet' in Samsung terms) turned on - including 'Automatically turn off AVR'
2. Denon AVR 1612 connected to TV's ARC HDMI input
3. xbmc media centre (with pulse-eight internal CEC adapter) plugged into the 'BD' HDMI input on the AVR
4. Pi plugged into 'Game' HDMI input on AVR

If the Pi is powered off it stops the ARC functionality from working on my TV. If I try for example to 'refresh device list' in the Samsung Anynet menu it doesn't detect my AVR - even though the AVR is turned on. It also stops the AVR from being turned off automatically.

If I unplug the HDMI cable from the Pi all is well.

I don't have the same CEC issues with my other media center (which has run Openelec, XBMC on W7 and now XBMC on W8) which has a pulse-eight internal CEC adapter.

A bit frustrating really as it lowers the WAF significantly!

I might try the removal of D14 as suggested but would rather not resort to that if possible.

ZZ600E3
Posts: 27
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Re: Unpowered Raspi breaking HDMI-CEC

Tue Aug 28, 2012 7:56 am

I did remove D14 and it has mostly resolved the issue. It crops up from time to time but rectifies itself without the need of the hard reset.

It's a bit sad that without spending more money on a cec - less cable as mentioned above that you evidently invalidate the warranty trying to fix this.

It does its job and for £25 its not a major loss if it breaks, but I'm surprised at the lack of chatter on this issue since I can not believe it's isolated.

I know my tv and av receiver are not capable of using the return channel on hdmi like the newer 3D sets can, could this be root of the cause and why it's so specific?

plexy
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Re: Unpowered Raspi breaking HDMI-CEC

Tue Aug 28, 2012 9:05 am

Hi ,

I have also removed D14 and has been a bit hit and miss, sometimes it does kick in automatically but
to be honest i have a media centre remote as a backup to save me getting out of bed to change:)

USB powered Pi,openelc with plex plugin using hompeplugins ..I cant complain too much if the tv remote doesn't work intermittantly but would be the icing on the cake.

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