T77568
Posts: 11
Joined: Sat Sep 22, 2018 4:25 pm

No HDMI Output Although TV is recognized by RPi 3 B+

Sat Sep 22, 2018 5:46 pm

Hello,

Early January 2018 I bought an ABOX Raspberry Pi 3 Modell B Starter Kit via Amazon for it to become my home theatre with libreelec/kodi.
It came with a SIMSUKIAN AC/DC adapter with 5V / 2.4A Output, a SanDisk Ultra 32GB SD card, some heatsinks to be attached to the processors and a black case.
LibreELEC (I don't recall the version anymore) was pre-installed on the SD card, inserted it, connected it to my TV and LibreELEC/Kodi booted up as expected.
Set up Kodi and everything was fine (could watch movies from my NAS, could control it via CEC (remote), etc.)... until about May.

Suddenly my TV (Sony Bravia RD45) would not recognize the RPi3B as HDMI input source anymore, which worked well until then.
The days before I noticed odd behaviour of the CEC controller (with my TV remote): it failed then worked again then failed and then there was no graphic output anymore at all.

At first I thought the RPi3B wouldn't boot, but it does boot as I can reach it via SSH.
I did the following troubleshooting:
  • Checking the boot logs via SSH. No oddities found there.
  • Setting hdmi_force_hotplug to 1 and boosting config_hdmi_boost didn't take effect.
  • Also I switched the cable and tried with other monitors, which all didn't work.
  • The interesting thing: The RPi3B actually recognized the TV over the HDMI cable - it just didn't seem to produce any graphic output (not even the "berry" and color-mix boot screen).
I dismissed this as hardware failure and bought myself a new Raspberry 1373331 Pi 3 Modell B+.
I used the same componentes as above except for the case, which B+ doesn't fit in anymore, and the heat sinks, which I have read are not needed anyways. Since then the RPi just lies flat on the TV desk with "natural" airflow around it.
I erased the SD card and re-installed it with LibreELEC 8.2.5 and it worked nicely... until start of September the whole thing happened again:
Suddenly the Pi wouldn't produce valid output signal for the TV (or any other monitor I connected) again, this time without any preceding CEC issues.
Again, it booted up and I could reach it via SSH, even the TV and its modes were recognized (see Details below).

Again, I thought this as really bad luck and got myself a replacement RPi3B+ from Amazon.
I put in the exact same SD card (didn't change anything on it) and viola, the screen was back on.
Deducing from this I dare to exclude the TV, the HDMI cable, the SD card and the power adapter from the list.

So I was happy again... for about ten days.
Just today the same behavior occurred as described above for a third time. :(
I made a second SD card with Raspbidian on it, which doesn't produce graphic output either.
The only thing I recall is that the Pi ran for about 4 hours straight without the TV being switched on, but its predecessors ran even longer.
This time I was also very careful to always shut down the Pi using the Kodi menu before unplugging it from power.

I will get another replacement from Amazon, but I wonder if this is reall really bad luck or something systemic.
So, what else could I do?
  • Are there methods to run a test program on the GPU?
  • Is there some detailled traces I might have missed?
  • Can it be overheating? (The RPi just lies on the wooden table below the TV in free air. It gets warm, but nothing out of the unusual. I do not overclock or anything.)
  • Is it possible that the TV sends some kind of HDMI killer command to the RPi that disables HDMI Output and somehow gets persisted? (However, booting without SD card or with a differen OS doesn't seem to bring it back).
Thank you for your advice.


PS: There are plenty of articles out there solving low HDMI signal or cable issues, but the only one I found describing a similar behaviour to mine is this: https://www.raspberrypi.org/forums/view ... p?t=194239
The final solution there was to get a replacement, in which my fate is twindling since I'm already getting my third replacement.



Details:

LibreElec:

Code: Select all

RPi3Bplus:/flash # cat /etc/os-release
NAME="LibreELEC"
VERSION="8.2.5"
ID="libreelec"
VERSION_ID="8.2"
PRETTY_NAME="LibreELEC (official): 8.2.5"
HOME_URL="https://libreelec.tv"
BUG_REPORT_URL="https://github.com/LibreELEC/LibreELEC.tv"
BUILD_ID="0beeae963db04e94b1d4457a8fcaa3c25bf2161a"
OPENELEC_ARCH="RPi2.arm"
LIBREELEC_ARCH="RPi2.arm"
LIBREELEC_BUILD="official"

LibreELEC's /flash/config.txt

Code: Select all

################################################################################
# Bootloader configuration - config.txt
################################################################################

################################################################################
# Memory (System/GPU configuration )
################################################################################

# Default GPU memory split (do not change if you do not know what you are doing)
  gpu_mem=128

# Configure GPU memory based on SDRAM size - overrides above setting
  gpu_mem_256=112
  gpu_mem_512=160
  gpu_mem_1024=256

################################################################################
# For overclocking and various other settings, see:
# https://www.raspberrypi.org/documentation/configuration/config-txt.md
################################################################################
# Set 'force_turbo=1' to disable dynamic overclocking and enable overclocking always.
force_turbo=0

# Make display smaller to stop text spilling off the screen
#
# Note that the overscan settings only affect the splash screen and not Kodi.
#
# If you experience overscan/underscan issues the best solution is to adjust
# your TV settings ("full pixel", "1-1 pixel" etc.). Alternatively, there is a
# calibration menu in the Kodi GUI.
# disable_overscan=1

# Force HDMI even if unplugged or powered off
hdmi_force_hotplug=1
# hdmi_group=2
# hdmi_mode=4
# config_hdmi_boost=4
# hdmi_safe=1


# Doesn't sent initial active source message.
# Avoids bringing CEC (enabled TV) out of standby and channel switch when
# rebooting.
#hdmi_ignore_cec_init=1

################################################################################
# License keys to enable GPU hardware decoding for various codecs
# to obtain keys visit the shop at http://www.raspberrypi.com
################################################################################

# decode_MPG2=0x00000000
# decode_WVC1=0x00000000

################################################################################
# End of default configuration
################################################################################

################################################################################
# Include distribution specific config file if it exists.
################################################################################
#[all]
#include distroconfig.txt

tvservice output when the HDMI cable is not connected:

Code: Select all

RPi3Bplus:~ # tvservice -n
[E] No device present
RPi3Bplus:~ # tvservice -m DMT
Group DMT has 1 modes:
  (prefer) mode 4: 640x480 @ 60Hz 4:3, clock:25MHz progressive
RPi3Bplus:~ # tvservice -s
state 0x12000a [HDMI DMT (4) RGB full 4:3], 640x480 @ 60.00Hz, progressive

tvservice output, when the HDMI cable connects the RPi to the TV:

Code: Select all

RPi3Bplus:~ # tvservice -n
device_name=SNY-SONY_TV
RPi3Bplus:~ # tvservice -m DMT
Group DMT has 7 modes:
           mode 4: 640x480 @ 60Hz 4:3, clock:25MHz progressive
           mode 9: 800x600 @ 60Hz 4:3, clock:40MHz progressive
           mode 16: 1024x768 @ 60Hz 4:3, clock:65MHz progressive
           mode 21: 1152x864 @ 75Hz 4:3, clock:108MHz progressive
           mode 35: 1280x1024 @ 60Hz 5:4, clock:108MHz progressive
           mode 58: 1680x1050 @ 60Hz 16:10, clock:146MHz progressive
           mode 83: 1600x900 @ 60Hz 16:9, clock:108MHz progressive
RPi3Bplus:~ # tvservice -s
state 0x12000a [HDMI CEA (16) RGB lim 16:9], 1920x1080 @ 60.00Hz, progressive

T77568
Posts: 11
Joined: Sat Sep 22, 2018 4:25 pm

Re: No HDMI Output Although TV is recognized by RPi 3 B+

Sat Sep 29, 2018 9:20 am

In the meantime I received the replacement of my RPi 3 B+, put the old SD card in and HDMI works again as it should. So, I deduce it was definitely a hardware failure of the RPi 3 B+... at least.

Just to make sure, I once again tried the old RPis with a Raspbidian installation on another SD: HDMI just doesn't work on these anymore.

However, I also realized the following:
My TV (Sony Bravia RD45) has two HDMI inputs: HDMI 1 with ARC and HDMI 2.
When I reestablished the replacement RPi 3 B+ the first time, the TV still didn't get an input signal on HDMI 1, but when I connected it to HDMI 2 everything worked fine.
Hence I tried connecting other HDMI devices to HDMI 1, which weren't detected either. HDMI 2 worked.
So I assume that in the meantime the TV's HDMI 1 was defecting too.
(Just for the record: I tried the old RPis on other working HDMI devices other than my TV and the Pis didn't work there either, so they are definitely broken)

In conclusion I think that the TV's defecting HDMI 1 was somehow able to ruin two Pi's HDMI output capabilities.

fruitoftheloom
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Re: No HDMI Output Although TV is recognized by RPi 3 B+

Sat Sep 29, 2018 10:45 am

T77568 wrote:
Sat Sep 29, 2018 9:20 am
In the meantime I received the replacement of my RPi 3 B+, put the old SD card in and HDMI works again as it should. So, I deduce it was definitely a hardware failure of the RPi 3 B+... at least.

Just to make sure, I once again tried the old RPis with a Raspbidian installation on another SD: HDMI just doesn't work on these anymore.

However, I also realized the following:
My TV (Sony Bravia RD45) has two HDMI inputs: HDMI 1 with ARC and HDMI 2.
When I reestablished the replacement RPi 3 B+ the first time, the TV still didn't get an input signal on HDMI 1, but when I connected it to HDMI 2 everything worked fine.
Hence I tried connecting other HDMI devices to HDMI 1, which weren't detected either. HDMI 2 worked.
So I assume that in the meantime the TV's HDMI 1 was defecting too.
(Just for the record: I tried the old RPis on other working HDMI devices other than my TV and the Pis didn't work there either, so they are definitely broken)

In conclusion I think that the TV's defecting HDMI 1 was somehow able to ruin two Pi's HDMI output capabilities.


I would assume that your TV shot a
voltage down the HDMi Cable:

https://en.wikipedia.org/wiki/HDMI

The RPi SoC is a VPU and ARM CPU.
adieu

My other Computer is an Asus CS10 ChromeBit running Chrome Operating System.
HP Envy 4500 Wireless Printer supported by HPLIP software in Raspbian Buster.
Raspberry Pi Model 2B v1.1

T77568
Posts: 11
Joined: Sat Sep 22, 2018 4:25 pm

Re: No HDMI Output Although TV is recognized by RPi 3 B+

Sun Sep 30, 2018 6:33 am

fruitoftheloom wrote: I would assume that your TV shot a
voltage down the HDMi Cable:
That is very probable.
And this seems to somehow have destroyed the VPU, but not the general capability to talk over the HDMI with the TV (since the Pi can still read out the TV's name and modes).

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Joel_Mckay
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Re: No HDMI Output Although TV is recognized by RPi 3 B+

Sun Sep 30, 2018 10:31 am

Sounds like a troublesome situation, as I had a cheap HDMI cable start to glitch up one machine whenever it heated up. RF shorts are not easily diagnosed with a regular ohmmeter... I would try a different TV input and HDMI cable... as there is a chance you may luck out like I did.

However, your story sounds like it could have a ground-loop related issue with your TV and power supply. Common problem for instrumentation, but a rare issue in consumer electronics unless the power supply is not properly grounded or is failing from boiled capacitors.
https://en.wikipedia.org/wiki/Ground_loop_(electricity)

Additional problems can emerge from ESD related issues if the Pi's power adapter is a counterfeit unit made without proper filters (or even a Varistor), as motors in old refrigeration compressors or sump-pumps can sometimes inject spikes back into the power line..
https://en.wikipedia.org/wiki/Electrostatic_discharge

Do both TV and Pi power supplies have the 3-pin-style wall plug with a shared power bar connected to a 3-pin socket?

Cheers,
J

T77568
Posts: 11
Joined: Sat Sep 22, 2018 4:25 pm

Re: No HDMI Output Although TV is recognized by RPi 3 B+

Sun Sep 30, 2018 4:55 pm

Thanks for your advices so far.

Joel_Mckay wrote: Do both TV and Pi power supplies have the 3-pin-style wall plug with a shared power bar connected to a 3-pin socket?
All 6 devices in that area, the TV, the Pi, the notebook's docking station, the cable modem, a LAN switch and the NAS are on the same bar/strip. It has an on/off switch and a surge protector, which so far I never had to reset.
The power bar itself is grounded, but the Pi's and the TV's power adapters are not.

Joel_Mckay wrote: However, your story sounds like it could have a ground-loop related issue with your TV and power supply. Common problem for instrumentation, but a rare issue in consumer electronics unless the power supply is not properly grounded or is failing from boiled capacitors.
https://en.wikipedia.org/wiki/Ground_loop_(electricity)
Both the power adapers (TV's and Pi's) are not grounded, so a ground loop could be possible.
The Pi itself is resting on a wooden table probably touching the TV's plastic foot. Maybe that grounded it, but it is highly unlikely. The first Pi model even had a plastic case around it.

If I understand that artice correctly, a ground loop would cause the HDMI signal to be noisy or disrupted. But there is binary data transfer over it (the PI gets the TV's name and modes correctly), but no image signal. If there was a ground loop, wouldn't it effect the "name and mode" communication as well?

Joel_Mckay wrote: Additional problems can emerge from ESD related issues if the Pi's power adapter is a counterfeit unit made without proper filters (or even a Varistor), as motors in old refrigeration compressors or sump-pumps can sometimes inject spikes back into the power line..
https://en.wikipedia.org/wiki/Electrostatic_discharge
That indeed could be an explanation.

My refrigerator is very old (from the looks of it way over 20 years).
It is on another circuit though, together with my PC.
When I switch on my PC's power bar, which also has some powerful speakers' power adapter plugged in, the corresponding surge sometimes blows.
However, this happens on another circuit and usually doesn't effect the TV's one.

If I turn the TV's power bar on, I could have thought sometimes heareing a click from the surge too, but so far I never had to reset that curcuit.
But it all indicates that voltage peaks maybe are the issue here that fries the apparently sensitive Pi.


So what can I possibly do? Better power bar? Better power adapter for the Pi?


Thank you.


Details:

The power bar's label reads:
AOBOER
GBKDS06A
Max. 3500W
16A250V~ 50 Hz
Up 1,0KV;Uc250V~;Ucc 3KV;TYP3

It is connected to the wall with a CEE 7/4" plug and offers 6 CEE 7/3" sockets (= European type Schuko sockets), in which the devices mentioned above are plugged in.
So, the power bar itself is grounded.

The Pi's Power adapter reads:
SIMSUKIAN
AV/DC ADAPTER
MODEL: SK02T-0500250V
INPUT: AC100-240V ~ 50/60Hz 0.35A
OUTPUT: 5V = 2.5A
S/N: 175101000299
MADE IN CHINA

It has a two pin Europlug, so it is not grounded.

The TV uses an external power adapter, which reads:
SONY 19.5V AC ADAPTER
MODEL: ACDP-085S03
INPUT: 100 V - 240 V ~ 1.0 A 50/60 Hz
OUTPUT: 19.5 V = 4.36 A
Parts No. / Seral No.: *149314712 0399401*
Made in Indonesia

It also has a two pin Europlug, so it is not grounded either.

Animotor
Posts: 3
Joined: Wed Sep 19, 2018 10:53 am

Re: No HDMI Output Although TV is recognized by RPi 3 B+

Sun Sep 30, 2018 5:52 pm

Hi,

I'm having situation that is in some aspects similar to this (https://www.raspberrypi.org/forums/view ... 2#p1369022). The difference is that in my case the Pi is able to send an image to one display but not to two other.

Could it be possible that the power surge breaks the VPU only partially so that it could work with some displays but not all?

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Joel_Mckay
Posts: 288
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Re: No HDMI Output Although TV is recognized by RPi 3 B+

Sun Sep 30, 2018 10:10 pm

T77568 wrote:
Sun Sep 30, 2018 4:55 pm
All 6 devices in that area, the TV, the Pi, the notebook's docking station, the cable modem, a LAN switch and the NAS are on the same bar/strip. It has an on/off switch and a surge protector, which so far I never had to reset.
The power bar itself is grounded, but the Pi's and the TV's power adapters are not.
Unfortunately, I am not really that familiar with euro plugs outside travel chargers... as I am in 120v land Canada =)
However, I am assuming the cable modem's coax input shield demanded a transformer based supply, or a grounded 3-pin adapter. Note, there are also lightning protection filters for these coax lines.
Historically, non-polarized 2-pin plugs were meant for transformer based equipment that naturally isolated the power lines from the adapter outputs. The "SK02T-0500250V" looks like a switching power supply, and that means with 2-pins it or the TV could swap the house power Neutral and Hot lines in some circumstances. Additionally, while most assume AC line Neutral means 0v, the ugly truth is code allows a DC offset to sit on the line (in some places it can be over 30vDC and still be considered within code.) You should disconnect your cables, and get an electrician to measure with a multi-meter each of these lines have matched polarity, and the potentials relative to earth/ground is code.
T77568 wrote:
Sun Sep 30, 2018 4:55 pm
If I understand that artice correctly, a ground loop would cause the HDMI signal to be noisy or disrupted. But there is binary data transfer over it (the PI gets the TV's name and modes correctly), but no image signal. If there was a ground loop, wouldn't it effect the "name and mode" communication as well?
i2c style i/o uses a different low speed bus that does not usually use tri-state digital or sensitive differential pair RF signals, the HDMI DDC lines are less likely to form a potential as the clock/data resister biased pins could in theory float to arbitrary signal levels above logic low (within reason).

T77568 wrote:
Sun Sep 30, 2018 4:55 pm
My refrigerator is very old (from the looks of it way over 20 years).
It is on another circuit though, together with my PC.
When I switch on my PC's power bar, which also has some powerful speakers' power adapter plugged in, the corresponding surge sometimes blows.
However, this happens on another circuit and usually doesn't effect the TV's one.
Unfortunately, those MOV in power supplies wear out, and will only take so many hits before they stop arresting spikes.
You should minimally add one or two clip-on Ferrite EMI noise filters to the equipment, tv, and power-bar power cords in your home (these are often inside those 2cm diameter cylindrical bumps you see on many computer power cords).

T77568 wrote:
Sun Sep 30, 2018 4:55 pm
So what can I possibly do? Better power bar? Better power adapter for the Pi?
Hard to know the actual source of the issue from where I am, but a local electrician could likely identify the issue origin. Isolation transformers are expensive, but there may be a cheaper option with a laptop power adapter since they are normally better built.
Personally, I would just get a 220v to 1.5A 12vDC transformer (will be much larger than a regular switching supply), add a 5A 5v DC-DC buck converter regulator off ebay, and ground the regulator (-) on the pi to the TV coax shield. This solution would allow the pi and cables to bias with whatever the TV is doing electrically.


@Animotor
Some older tv/monitors do not support libCEC communication, and your thread does not seem related to bricking HDMI ports. I would do some searches for other people with the same LCD model you are having issues with to see if CEC is supported. You can try to manually force the specific output resolution in config.txt . ;-)

Cheers,
~J~

T77568
Posts: 11
Joined: Sat Sep 22, 2018 4:25 pm

Re: No HDMI Output Although TV is recognized by RPi 3 B+

Mon Oct 01, 2018 3:48 pm

Thank you, Joel_Mckay for your detailled analysis.
Joel_Mckay wrote: However, I am assuming the cable modem's coax input shield demanded a transformer based supply, or a grounded 3-pin adapter. Note, there are also lightning protection filters for these coax lines.
No, the cable modem uses an Europlug too, which is not grounded. I suppose (without knowing for sure) that the coax is grounded somewhere in the splitter outside the building.

Joel_Mckay wrote: Historically, non-polarized 2-pin plugs were meant for transformer based equipment that naturally isolated the power lines from the adapter outputs. The "SK02T-0500250V" looks like a switching power supply, and that means with 2-pins it or the TV could swap the house power Neutral and Hot lines in some circumstances. Additionally, while most assume AC line Neutral means 0v, the ugly truth is code allows a DC offset to sit on the line (in some places it can be over 30vDC and still be considered within code.) You should disconnect your cables, and get an electrician to measure with a multi-meter each of these lines have matched polarity, and the potentials relative to earth/ground is code.
I measured the polarity with my multi-meter with either TV or Pi and both plugged in. In any case it didn't change.
Also the voltage between Phase/Line and Neutral is 229 to 230 V, which is the same between Phase/Line and Ground.

Joel_Mckay wrote: i2c style i/o uses a different low speed bus that does not usually use tri-state digital or sensitive differential pair RF signals, the HDMI DDC lines are less likely to form a potential as the clock/data resister biased pins could in theory float to arbitrary signal levels above logic low (within reason).
So, in other words, the "name and mode" communication over HDMI is more robust against a ground loop than the image communication?

Joel_Mckay wrote: You should minimally add one or two clip-on Ferrite EMI noise filters to the equipment, tv, and power-bar power cords in your home (these are often inside those 2cm diameter cylindrical bumps you see on many computer power cords).
The Pi's "SK02T-0500250V" power adapter already has one of those on it's DC wire close to the Pi. The TV and the power bar itself don't as far as I can see, so I will equip them.

Joel_Mckay wrote: Hard to know the actual source of the issue from where I am, but a local electrician could likely identify the issue origin. Isolation transformers are expensive, but there may be a cheaper option with a laptop power adapter since they are normally better built.
Personally, I would just get a 220v to 1.5A 12vDC transformer (will be much larger than a regular switching supply), add a 5A 5v DC-DC buck converter regulator off ebay, and ground the regulator (-) on the pi to the TV coax shield. This solution would allow the pi and cables to bias with whatever the TV is doing electrically.
I'll try the laptop adapter first since I have one spare. If that doesn't help I will (try to) build the DC array you suggested.


Thanks for your help.

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Joel_Mckay
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Re: No HDMI Output Although TV is recognized by RPi 3 B+

Mon Oct 01, 2018 10:55 pm

T77568 wrote:
Mon Oct 01, 2018 3:48 pm
No, the cable modem uses an Europlug too, which is not grounded. I suppose (without knowing for sure) that the coax is grounded somewhere in the splitter outside the building.
I am assuming you already tried a different / newer HDMI cable and signal source to confirm the first HDMI socket is dead.
:-)
However, try the meter in both AC and DC mode to confirm the potential from the exposed coax (tv and modem) sheath and earth/ground.
Both of these should read very close to 0v on the multi-meter.
T77568 wrote:
Mon Oct 01, 2018 3:48 pm
I measured the polarity with my multi-meter with either TV or Pi and both plugged in. In any case it didn't change.
Also the voltage between Phase/Line and Neutral is 229 to 230 V, which is the same between Phase/Line and Ground.
Use the meter in both AC and DC mode to confirm the potential from the Neutral and earth/ground.
(it is normal to see about 0vAC , but rare to see a perfect 0vDC as I said before.)
Also try the meter in both AC and DC mode to measure the Pi's +5vDC and Ground pins relative to the exposed coax sheath, and earth/ground.
The meter ideally should read very close to +5vDC (0vAC) potential, and 0vDC (0vAC) for GND. Keep your fingers clear, as I suspect a little surprise may be hiding in that power supply design that could potentially damage additional chips. ;-)
T77568 wrote:
Mon Oct 01, 2018 3:48 pm
So, in other words, the "name and mode" communication over HDMI is more robust against a ground loop than the image communication?
In general, open-collector style drivers are quite resilient to supply fluctuations, but severe events can still punch though the logic.
Once every few years, I see a switching power supply design start to inject nasty transients as they start a failure mode, and it is difficult to catch before the capacitors start to fail.
T77568 wrote:
Mon Oct 01, 2018 3:48 pm
The Pi's "SK02T-0500250V" power adapter already has one of those on it's DC wire close to the Pi. The TV and the power bar itself don't as far as I can see, so I will equip them.
It is there to help reduce the switching noise entering your device, and functions the same as other EMI clip on filters.
T77568 wrote:
Mon Oct 01, 2018 3:48 pm
I'll try the laptop adapter first since I have one spare. If that doesn't help I will (try to) build the DC array you suggested.
I had a quick look around, and it looks like almost everyone has gone with the cheaper/smaller switch-mode versions for consumer plug-ins these days. I assume you know about the dangers of working with line voltages if you own a meter. :-)

Cheers,
~J~

T77568
Posts: 11
Joined: Sat Sep 22, 2018 4:25 pm

Re: No HDMI Output Although TV is recognized by RPi 3 B+

Tue Oct 02, 2018 7:58 pm

Joel_Mckay wrote: I am assuming you already tried a different / newer HDMI cable and signal source to confirm the first HDMI socket is dead.
:-)
Yes. I have tried two HDMI cables and two HDMI sources (the Pi and the Laptop) - any combination worked with HDMI 2, neither combination worked with HDMI 1. But they worked a few months ago.

Joel_Mckay wrote: However, try the meter in both AC and DC mode to confirm the potential from the exposed coax (tv and modem) sheath and earth/ground.
Both of these should read very close to 0v on the multi-meter.
There is a 33 mV potential between the Pi's ground (GPIO PIN 6 or HDMI's sheath) and the sheath of the modem's coax.
Joel_Mckay wrote: Use the meter in both AC and DC mode to confirm the potential from the Neutral and earth/ground.
AC: neutral to ground = 0
DC: neutral to ground = 0
Joel_Mckay wrote: Also try the meter in both AC and DC mode to measure the Pi's +5vDC and Ground pins relative to the exposed coax sheath, and earth/ground.
DC: GPIO PIN 2 (+5V) vs. GPIO PIN 6 (GND) = 5,15 V
DC: GPIO PIN 2 (+5V) vs. coax sheath = 5,18 V

DC: GPIO PIN 6 (GND) vs. coax sheath = 0,03 V

AC: all 0


While measuring the potentials between the different pins I discovered the following:

How to fry your Raspberry Pi 3 Model B+

If you incidentally connect GPIO PIN 1 (+ 3V) and 2 (+ 5V) on the RPi 3 B+, it will shut down and never come back up again.
The GPIO PIN 2 (+ 5V) and 4 (+ 5V) will still have +5V against PIN 6 (GND), but PIN 1 (+ 3V) will be 0 and the Pi won't start at all.

I "verified" this with the other RPi 3 B+, whichs HDMI was already defecting: connect PIN 1 and 2 and the Pi will be dead (PIN 1 is down to 0).

Unfortunately GPIO pins 1 and 2 are very exposed and it is likely to connect them by accident, like in my case by slipping off with my meter.

I don't suppose that there is a way to reenable my Pi after this?

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Joel_Mckay
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Re: No HDMI Output Although TV is recognized by RPi 3 B+

Wed Oct 03, 2018 12:44 am

Unfortunately, over-voltage on the 3.3 logic chips is fairly bad, but there is a remote chance it tripped the regulator safety.
i.e. unplug the power-adapter and cables, give it 60 seconds for the safety circuits or poly-fuse to reset, and power back up without the current sdcard (these usually fail-closed/short-out-internally).

Hard to be certain, but it looks like that current 5vDC power adapter is abnormal, and may be ringing well above the 5v line (need a scope to check for ripple/spikes).

Normally I private message people about this kind of thing...
But if you are interested, I can mail you a free gen1 (3-axis only) pi3/3B+ PC ATX motherboard we have been developing for colour 3D-printing, robotics, laser engravers, and CNC mills: http://www.micrometer.xyz/cdn/node/32
Our gen3 version will be available later this month at our club, and I may have a spare pi3 from an old job around if you can't grab a new one for whatever reason. You can email me using the project website contact form: http://www.micrometer.xyz/cdn/node/2
...as I would minimally need to know who and where to send our free alpha motherboard...
In general, we have been gifting these kits to developers that make the great FOSS projects we have enjoyed over the years, and have a contest running in North America for a free gen3 8-axis board on till Oct 31.

I hope I cheered you up a bit at least.. ;-)
~J~

T77568
Posts: 11
Joined: Sat Sep 22, 2018 4:25 pm

Re: No HDMI Output Although TV is recognized by RPi 3 B+

Wed Oct 03, 2018 7:33 pm

Joel_Mckay wrote: Unfortunately, over-voltage on the 3.3 logic chips is fairly bad, but there is a remote chance it tripped the regulator safety.
i.e. unplug the power-adapter and cables, give it 60 seconds for the safety circuits or poly-fuse to reset, and power back up without the current sdcard (these usually fail-closed/short-out-internally).
I retried again today after it having been off power for about 20 hours, but it didn't come up again. The GPIO pin 1 (+ 3V) is still at 0.
So, I guess it's gone for good.
Fortunately the SD card seems to have survived the accident, since I can still access it with my laptop.

Joel_Mckay wrote: Hard to be certain, but it looks like that current 5vDC power adapter is abnormal, and may be ringing well above the 5v line (need a scope to check for ripple/spikes).
I see. I have ordered another one from a different manufacturer. Maybe that will do better.
Unfortunately I don't have an oscilloscope at hand, but I have a laboratory power supply with adjustable output voltage somewhere. Just have to re-wire the output into micro-usb. That should do the trick of getting exactly 5V, but will also be the worst overkill ever for that purpose. :D

Joel_Mckay wrote: Normally I private message people about this kind of thing...
But if you are interested, I can mail you a free gen1 (3-axis only) pi3/3B+ PC ATX motherboard we have been developing for colour 3D-printing, robotics, laser engravers, and CNC mills: http://www.micrometer.xyz/cdn/node/32
Thank you very much for your kind offer, but I wouldn't know what to do with your motherboard, yet how to assemble a CNC mill. I'm more of a software guy. But I like to watch the This Old Tony machining/milling videos on Youtube very much. :D
However, a friend of mine is in mechatronics, so maybe he has interest in that motherboard. I will forward the links you provided if I may.
But since we are both in Europe, I'm afraid your challenge won't apply.
Joel_Mckay wrote: Our gen3 version will be available later this month at our club, and I may have a spare pi3 from an old job around if you can't grab a new one for whatever reason.
Again, thank you very much for your kindness, but I wouldn't dare to deliver you of your own Pi.
I have already ordered 2 new Pies - It wouldn't be fair to send them back to Amazon since I have fried them myself yesterday, or would it? ;) - a new power adapter and a number of clip-on Ferrite EMI noise filters. Luckily these things aren't that expensive.
Joel_Mckay wrote:I hope I cheered you up a bit at least.. ;-)
Yes, you did. Thank you very much.

T77568
Posts: 11
Joined: Sat Sep 22, 2018 4:25 pm

Re: No HDMI Output Although TV is recognized by RPi 3 B+

Sun Oct 07, 2018 7:51 am

I received another two Rapberry Pi 3 Model B+ (1373331) yesterday, installed the SD card id it worked again.
These two were manufactured by element14 whereas the previous three were manufactured by RS Components Ltd and Allied Electronics Inc.

GPIO Voltages with the same SK02T-0500250V power adapter as before are:

DC: GPIO PIN 2 (+5V) vs. GPIO PIN 6 (GND) = 5.08 V
DC: GPIO PIN 1 (+3.3V) vs. GPIO PIN 6 (GND) = 3.28 V

DC: GPIO PIN 6 (GND) vs. coax sheath, with the TV turned on = 0,06 V
DC: GPIO PIN 6 (GND) vs. coax sheath, with the TV turned off = 0 V

Well, let's see how long they'll do.



Details:

My first Pi was (HDMI not working anymore):
896-8660 Raspberry Pi 3 Model B
FCC ID: 2ABCB-RPI32
Made in United Kingdom
RS Components

The next two were (now both dead):
137-3331Raspberry Pi 3 Model B+
FCC ID: 2ABCB-RPI3BP
Made in United Kingdom
RS Components

The latest two are (still working):
137-3331Raspberry Pi 3 Model B+
FCC ID: 2ABCB-RPI3BP
Made in UK
element14

User avatar
Joel_Mckay
Posts: 288
Joined: Mon Nov 12, 2012 10:22 pm
Contact: Website

Re: No HDMI Output Although TV is recognized by RPi 3 B+

Sun Oct 07, 2018 8:04 am

That output sounds a lot cleaner (especially if under load), and I'm glad to hear you are back up and running.
=)

Cheers,
~J~

T77568
Posts: 11
Joined: Sat Sep 22, 2018 4:25 pm

Re: No HDMI Output Although TV is recognized by RPi 3 B+

Thu Jan 03, 2019 7:08 pm

Unfortunately my luck didn't last for long. :(

As of today, the Rapberry Pi 3 Model B+ (1373331) produced by Element14 refused to send a HDMI signal again, while otherise operating normally (SSH access possible).
It has been connected to the SK02T-0500250V power adapter just like all the other devices that have failed (and which has a button power on/off toggle switch).
This time I really made sure to always power the Pi down before pressing the power switch to shut off and waitied after all other devices (TV, cable modem, ...) had been powered before I turned the Pi on.
Obviously this had been for naught.

Interestingly, measuring the GPIO PIN 1 (+3.3V) vs. GPIO PIN 6 (GND) read 0V (which indicates that the Pi is dead once again) for the third time I measured, after the first two or so reading produced about +3.12V.
I really doubt having connected GPIO PIN 1 (+3.3V) and GPIO PIN 2 (+5V) by accident this time, since I had been extra careful.
Also the Pi had been in a protective case all the time.


Now I'm making a last try with the second Rapberry Pi 3 Model B+ (1373331) produced by Element14 I so foresightedly bought.
This time connected it to the new Aukru Power BS-24W0503000WB power adapter, which has no power on/off button at all.
So it will be turned off and on together with the power bar.
I had to add a clip-on Ferrite EMI noise filter to this power adapter though, since it didn't have one on its own.


Just for the record, the readings for the new Rapberry Pi 3 Model B+ (1373331) produced by Element14 and connected to the Aukru Power BS-24W0503000WB power adapter are:

DC: GPIO PIN 2 (+5V) vs. GPIO PIN 6 (GND) = 5.22 V
DC: GPIO PIN 1 (+3.3V) vs. GPIO PIN 6 (GND) = 3.28 V

DC: GPIO PIN 6 (GND) vs. coax sheath, with the TV turned on = 0.05-0.06 V
DC: GPIO PIN 6 (GND) vs. coax sheath, with the TV turned off = 0.00-0.01 V


Let's see how long this lasts.


Details:

The new adapter reads:
Aukru Power
MODEL: BS-24W0503000WB
INPUT: 100-240V~
50/60Hz 0.6A Max
OUTPUT: 5V = 3000mA
MADE IN CHINA

User avatar
Joel_Mckay
Posts: 288
Joined: Mon Nov 12, 2012 10:22 pm
Contact: Website

Re: No HDMI Output Although TV is recognized by RPi 3 B+

Thu Jan 03, 2019 8:10 pm

Maybe add a HDMI Switch between the TV and your pi, as a $7 part is a less painful loss.

The pi3/pi3b+ ATX PC infinity motherboard offer is still valid if you are interested in covering the shipping from Canada.
You can contact me though the online form if you like: https://www.micrometer.xyz/cdn/node/2
Cheers, ;-)
J

andrum99
Posts: 574
Joined: Fri Jul 20, 2012 2:41 pm

Re: No HDMI Output Although TV is recognized by RPi 3 B+

Thu Jan 03, 2019 11:03 pm

T77568 wrote:
Sun Sep 30, 2018 6:33 am
fruitoftheloom wrote: I would assume that your TV shot a
voltage down the HDMi Cable:
That is very probable.
And this seems to somehow have destroyed the VPU, but not the general capability to talk over the HDMI with the TV (since the Pi can still read out the TV's name and modes).
The TV's name and modes are accessed using the DDC lines, which are separate from the lines that carry the picture. The DDC bus on HDMI is actually the same one that was retrofitted to VGA some years ago to enable the same facility.

T77568
Posts: 11
Joined: Sat Sep 22, 2018 4:25 pm

Re: No HDMI Output Although TV is recognized by RPi 3 B+

Sun Jan 06, 2019 4:26 pm

Joel_Mckay wrote:
Thu Jan 03, 2019 8:10 pm
Maybe add a HDMI Switch between the TV and your pi, as a $7 part is a less painful loss.
I did so now.

I added a VIVANCO 47/80 01 Automatic HDMI 2>1 switcher inbetween the Pi and the TV.
HDMI 1 is connected to the Pi, HDMI 2 is connected to my Laptop and the switcher's output is connected to the TV.
Let's see if that prolongates the Pi's lifetime.

Interestingly I found that when HDMI 2 is connected to my Laptop, even though when the Laptop is powered off and even though HDMI 1 (the Pi) is switched on, the CEC, with which I usually control the Pi's KODI via the TV's remote, doesn't work. KODI's CEC Plugin states that it is initialized correctly, recognizes the TV source, but the remote's signals don't seem to get through.
I have to unplug HDMI 2 completely for the remote to reach the PI over the HDMI switch.
Joel_Mckay wrote:
Thu Jan 03, 2019 8:10 pm
The pi3/pi3b+ ATX PC infinity motherboard offer is still valid if you are interested in covering the shipping from Canada.
You can contact me though the online form if you like: https://www.micrometer.xyz/cdn/node/2
I asked my tech-savy friend if he has use for this board, but he is busy with other projects right now and I find myself unable to utilize such a think.
But thank you for the offer.


Details:

The labels on the HDMI switcher read:
VIVANCO
47078 / 47/80 01
Vivanco GmbH, Ewige Weise 15,
22926 Ahrensburg/Germany, www.vivanco.com
47-37315
MADE IN GERMANY

T77568
Posts: 11
Joined: Sat Sep 22, 2018 4:25 pm

Re: No HDMI Output Although TV is recognized by RPi 3 B+

Sun Jan 06, 2019 4:52 pm

When I was reading the labels from the VIVANCO 47/80 01 Automatic HDMI 2>1 switcher, I noticed something:

As a touched the unconnected HDMI 2 female port, I got electrocuted... twice!

The setup is as follows: The Pi is connected to HDMI 1 of the switcher, HDMI 2 of the switcher is unplugged, the switcher itself is connected to the TV. The Pi is powered on and sending some signal to the TV.

It appears that some voltage builds up on HDMI 2's shield during operation.
If I discharge it, it takes a few minutes to build again.

mkz
Posts: 1
Joined: Sun Mar 17, 2019 7:44 pm

Re: No HDMI Output Although TV is recognized by RPi 3 B+

Sun Mar 17, 2019 7:56 pm

Had to register just to ask if your setup is still working? I have LG TV and just ordered my third pi. Sounds like I have exact the same issue. One day the hdmi signal is just lost. I can SSH to the pi, but nothing works. EDID info is there and the tv recognizes the device.

Dynamho
Posts: 1
Joined: Sat May 25, 2019 1:23 pm

Re: No HDMI Output Although TV is recognized by RPi 3 B+

Sat May 25, 2019 1:48 pm

This is a grounding issue that occurs due to SMPS emi filter.
This filter only works if it is grounded, and if it is missing the circuits ground will develop an AC potential that will contaminate HDMI and USB signaling.
The fix is to first ground the TV, this can be done by using a powerbar that has coax connetors and running a cable from the output connector to the TV cable input.
The raspberry can be grounded buy buying a power adapter that is grounded, or you could run a ground wire from the circuit pcb, but that would require soldering and a cable ground block.

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