TimeWalker
Posts: 4
Joined: Mon Jul 13, 2015 7:07 pm

RPi2 HDMI woes

Mon Jul 13, 2015 7:42 pm

Hello there, good people.

Long story short - I was given a Pi2 by a colleague, who managed to shock it with an el-cheapo Chinese AC adapter on it's first power sequence. After visual inspection and electrical testing I have managed to re-soldered a pair of tantalum caps near by the uUSB socket and the Pi started reacting to external power source and prepped uSD card. And yes, the person who gave it to me waited a couple of days for polyfuse to recover, didn't help much.

I've burned 05-05-2015 Raspbian on the card and started tampering with the Pi, but it didn't display any image through HDMI on my Samsung T22B300 (monitor-TV with a single HDMI port, no CEC), nor on my dumb Toshiba NTSC 32C100U1 (two HDMI ports, CEC support), saying No Signal. After playing with it some more I've decided to go the SSH route after determining the IP address my router has leased to the Pi via DHCP. It worked .. and so did TightVNC via iTeleport on my Mac.
Image

So started toying with config.txt and quickly determined that hdmi_safe allowed it to boot with image being displayed on just one single HDMI port on my Toshiba, but Samsung kept saying No Signal regardless. Second input on Toshiba would show up jumpy and the image would appear and disappear constantly... there's one BUT.
The image had a severe interference and red color dominance.
After reading what hdmi_safe brings I've commented it back up and started switching the config array it sets on and off. It came down to having to use DMT (group=2) and boost no lower than 4, the rest didn't matter for Toshiba. So I ended up with hdmi_mode=39 and hdmi_group=2, having config_hdmi_boost=4.
state 0x120016 [DVI DMT (39) RGB full 16:9], 1360x768 @ 60.00Hz, progressive. Tried changing pixel encoding to no avail.
Image

I've tried prepping the card both from Ubuntu and OSX dd as well as from WIndows Win32DiskImager, which everything ended up being the same. I've used the Asus Nexus 7 charge (2A) to power the Pi and a pretty expensive 1.5m HDMI cable from Sonorous. I've tried swapping the charge to a Lumia 920 fast charger, Huawei 4G modem DC wall adapter and an iPad charger. I've tried other HDMI cables, including a short 15cm cable with good shielding - same story, red interferes and dominates other color components. I couldn't get any image on friend's LG 1080p screen, nor on a couple of Philips HDMI screens at the office.

I then decided to try Ubuntu Mate since this is a Pi2, allowing for native ARMv7 code. To my surprise, the red component has completely vanished, resulting a pretty crisp image comprised of blue and green hue colors on my Toshiba.. I've tried everything again on the Sammy monitor-TV and got the same No Signal as with Raspbian. I can dump EDID from Sammy though whilst it's connected, so I'm not too certain how is this even possible .. means it negotiates handshake, but refuses to display anything.

EDID: http://pastebin.com/raw.php?i=My7HZY4g

Does anyone have any experience in fixing this kind of issue or this thing is toast? I have hot air gun reflow station and as last resort I was gonna try and re-work the HDMI socket.. but before I do, perhaps it's a software issue? Haven't bought it myself so not loosing much here anyway and have a Synology box which is capable of pretty much the same, but would be cool to have it fixed for Kodi at least.
Thanks in advance.

Best Regards,
TW

P.S. when kernel inits, it looks somewhat similar to this awful red tinted snow- https://www.youtube.com/watch?v=FHucCn1PstM

TimeWalker
Posts: 4
Joined: Mon Jul 13, 2015 7:07 pm

Re: RPi2 HDMI woes

Tue Jul 14, 2015 2:53 pm

Okay, recalled I have an old WDTV Live which uses a 3.5mm to RCA as well, I've taken the cable and after some tinkering (the plug didn't quite comply with what the Pi was expecting pin-wise) I got the image on composite input... HDMI would still be preferable though :cry:

Tom_A
Posts: 272
Joined: Fri Dec 06, 2013 8:34 am

Re: RPi2 HDMI woes

Tue Jul 14, 2015 4:32 pm

I seem to remember having issues when using one HDMI cable that went away when switching to a different brand. The "bad" HDMI cable worked fine with other devices. If you have a few HDMI cables handy and have not tried switching between them, that would be a good place to start.

TimeWalker
Posts: 4
Joined: Mon Jul 13, 2015 7:07 pm

Re: RPi2 HDMI woes

Tue Jul 14, 2015 7:22 pm

Thanks, but I've tried at least 4 cables I have around. I know one that is acting dodgy with my laptop refusing to passthrough sound, so I didn't expect much from it. Tried a little short cable I use to connect the input to a HDMI switch box, the cable I have my Mini connected, the PS3 cable and a DVR cable - nada. Neither of them worked. I also found a Chromecast DC adapter I had laying around (850mA) and it didn't help much.

After pressing down on a coil closest to HDMI pin 18 (5V) the interference seemed to decrease and letting it go brought it back. I was desperate and did re-work the HDMI socket and nearby coil array (L4 to L7) with flux and some lead solder ...which lead me nowhere - same old red snow.

Tom_A
Posts: 272
Joined: Fri Dec 06, 2013 8:34 am

Re: RPi2 HDMI woes

Wed Jul 15, 2015 4:17 pm

So, the next step, should you decide to continue, is probably to buy another RPi and see if that works. Something was probably damaged that's not going to be easy to fix. Anyone else who knows how to fix the HDMI hardware on a Raspberry Pi should probably chime in now. The board should still be useable for projects that don't use the video out and at least you have composite video access. If you wish to use HDMI though, looks like you need to buy another one.

drgeoff
Posts: 9916
Joined: Wed Jan 25, 2012 6:39 pm

Re: RPi2 HDMI woes

Wed Jul 15, 2015 4:46 pm

Tom_A wrote:Anyone else who knows how to fix the HDMI hardware on a Raspberry Pi should probably chime in now.
That I am chiming in now does not mean that I claim to know how to fix the HDMI hardware.

AFAIK there are no significant differences between the HDMI hardware on all RPi models. Full schematics for some RPi models are available. Except for some protection diodes there are only the HDMI lines connected directly to the SoC.

If you want pristine HDMI, get another RPi.

TimeWalker
Posts: 4
Joined: Mon Jul 13, 2015 7:07 pm

Re: RPi2 HDMI woes

Wed Jul 15, 2015 6:26 pm

Thing is, I didn't opt for a Pi myself, I was just given one in an attempt to fix it, which I did .. well, to a certain extent. I gave it back to the person who had originally toasted it, they have another RPi2 being used in the household that works. I also gave along my uSD card w/ Raspbian burned and my HDMI cable to check whether the power adapter/cable is the culprit or it's both of my TVs that are refusing to behave (I still want to believe it's not the PCB). If they get back to me saying no signal is coming out on HDMI or it's crippled with red noise then we know for sure the thing is still troubled.

I did look at B+ schematic but couldn't really see any HDMI circuit except the port pinout. Guess earlier models have more details schematics on the subject, will have a look.

SanPrashant2317
Posts: 3
Joined: Tue Jul 21, 2015 5:59 pm

Re: RPi2 HDMI woes

Wed Jul 22, 2015 3:06 am

TimeWalker wrote:Okay, recalled I have an old WDTV Live which uses a 3.5mm to RCA as well, I've taken the cable and after some tinkering (the plug didn't quite comply with what the Pi was expecting pin-wise) I got the image on composite input... HDMI would still be preferable though :cry:


Are telling that ur RASPBERRY PI 2 WORKING USING RCA CABLES ON SIMPLE TV?????

User avatar
rpdom
Posts: 15577
Joined: Sun May 06, 2012 5:17 am
Location: Chelmsford, Essex, UK

Re: RPi2 HDMI woes

Wed Jul 22, 2015 6:53 am

SanPrashant2317 wrote:
TimeWalker wrote:Okay, recalled I have an old WDTV Live which uses a 3.5mm to RCA as well, I've taken the cable and after some tinkering (the plug didn't quite comply with what the Pi was expecting pin-wise) I got the image on composite input... HDMI would still be preferable though :cry:


Are telling that ur RASPBERRY PI 2 WORKING USING RCA CABLES ON SIMPLE TV?????
The Pi has a Composite Video out, as well as HDMI. You can't use both at the same time. The Pi 2B (and A+/B+) use a 4-pole 3.5mm plug for audio and video output. If you get the [b/correct[/b] cable with a 4-pole plug one and and RCA connectors the other you can connect that to the video and audio inputs of many TVs (not the antenna/aerial input).

Composite video is very low quality, like an old TV.

Make sure you get a cable suitable for Raspberry Pi. There are different cables that look the same. Some work. Some don't.

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