EEVBlog #1145 - Dumpster Diving 4K TV

[EEVblog]

Dave finds a 65" 4K UHD LG LCD TV in the dumpster!
Will it work?
Bonus teardown included.

[ericloewe]

It would be interesting to see if inputs controlled by the big custom ASIC work. In other words, playing video from USB Mass Storage, Wireless Display and connecting to the internet. If those (and the tuner) all work, it should still be worth a couple hundred bucks, like for a business which just keeps some videos going in an infinite loop and really wants to do so on a huge panel.

It would also be interesting to see how it behaves if you use a native 4K input and maybe if you disable some of the image "enhancement" features. Maybe it's just the scaler and maybe it gets bypassed when not needed?

I assume the original remote for it is an expensive piece of crap, because the one they included with the 2015 models is an expensive piece of crap that seems only slightly more usable than the 2014 model. Fortunately, a generic LG IR remote probably works fine - if you can't get the Android remote control app to work without setting it up with a real remote, that is.

I might as well mention an occasional glitch that my 2015 LG 4K unit has: The image will occasionally end up with a nasty grey overlay (think analog TV static, but with no motion) until the TV is rebooted. IIRC, it affects both the input and the TV's menus/overlays, so it's probably unrelated.

[johnlsenchak]

Please  do more troubleshooting  on this 4K  television , once you get into the new lab 

[NiHaoMike]

Go back to the TV with the bad screen and get the motherboard from it?

[edy]

I picked up an old Sony Bravia looking relatively in good nick but it wouldn't power on fully. The red light gave some blink-pattern which you use to look up an error code. It turns out that when I unplugged a ribbon cable going from the main power supply to some other board (one of the inverter power boards on side of TV) by fluke as I was trouble-shooting the TV turned on and worked like a charm!!! 

As it turns out, that cable was being used to report back to the power supply any faults or errors in the other boards. Unplug the cable (I think it had like 9 pins, maybe more) and the supply no longer had any clue if there was a potential fault and powered up the entire system! I've tested it fully and there are no problems with performance whatsoever!!! 

However not wanting a potential overheating or fault to not be detected (now that I've defeated the safety circuit on the TV) I only use this TV for myself and it is not mounted on a wall. That way if I smell any sign of trouble I can cut the power. It is also on a powerbar which is off when I am not around (so not even on standby).

[SeoulBigChris]

I did some HDMI designs in that timeframe. Is the HDMI input processor an Analog Devices part by chance? If so, I might have a spare chip.

[-gb-]

It could be a connector. Looks like the HDMI Data is not captured right. HDMI has a differential pair for the clock and pairs for the colors. When a color is missing, the image just looks tinted, but when the clock is missing, you get garbage. I would suspect a connector, follow the signal path!
Greetings from Germany!

[Wan Huang Luo]

Hi Dave,

Big fan of your show. Last night I watched your episode with great interest. My wife loves the shows where you bring your little one to open fan mail! Anyway, I found that the mainboard can be sourced for $280 or so after looking up its part number, but that's not the EEVblog way. I'm looking forward to seeing what the issue is, if you find out the fix.

Echoing ericloewe's suggestion above; it has USB inputs. Presumably you can put a USB stick with video content into that monitor, and see if it plays anything. If it does, then you've got a real bobby dazzler digital picture frame and media player!

[thm_w]

I assume the original remote for it is an expensive piece of crap, because the one they included with the 2015 models is an expensive piece of crap that seems only slightly more usable than the 2014 model. Fortunately, a generic LG IR remote probably works fine - if you can't get the Android remote control app to work without setting it up with a real remote, that is.

Maybe dave/david has a phone with IR emitter, Its also possible to buy one that sticks into the headphone jack. That or a USB air mouse type remote should work. Many options.

Big fan of your show. Last night I watched your episode with great interest. My wife loves the shows where you bring your little one to open fan mail! Anyway, I found that the mainboard can be sourced for $280 or so after looking up its part number, but that's not the EEVblog way. I'm looking forward to seeing what the issue is, if you find out the fix.

Echoing ericloewe's suggestion above; it has USB inputs. Presumably you can put a USB stick with video content into that monitor, and see if it plays anything. If it does, then you've got a real bobby dazzler digital picture frame and media player!

Yeah hopefully USB or ethernet just works, then you don't really need HDMI in.
As a last resort a youtube commenter has offered their mainboard from a unit with a cracked panel.

[SeoulBigChris]

It could be a connector. Looks like the HDMI Data is not captured right.

Yes, I’ve seen a faulty connector cause this behavior, during factory testing of an hdmi product. But I lean towards the chip because Dave reported that other HDMI inputs didn’t work, either.

I’ve also seen this when the HDMI chip wasn’t initialized properly. For me, this was usually just a hiccup during development testing, say I reset the micro but not the HDMI chip during debugging. I suppose something similar could happen on a finished product, if the reset sequence was messed up for some reason - a bad voltage maybe?

[rx8pilot]

I have a $10k Sony OLED on my bench with a dead scaler chip. Took quite a bit of time to track it down too - but I don't think it is practical to repair the PCB at this time. Sony wants $1850 for the whole board.

Curious if this one has a decoder or scaler gone bad - if it is common enough to replace it.

[SeoulBigChris]

I have a $10k Sony OLED on my bench with a dead scaler chip. Took quite a bit of time to track it down too - but I don't think it is practical to repair the PCB at this time. Sony wants $1850 for the whole board.

Curious if this one has a decoder or scaler gone bad - if it is common enough to replace it.

Do you have a part number? Unlikely that I have it, but I might be able to steer you to one.

[rx8pilot]

I have a $10k Sony OLED on my bench with a dead scaler chip. Took quite a bit of time to track it down too - but I don't think it is practical to repair the PCB at this time. Sony wants $1850 for the whole board.

Curious if this one has a decoder or scaler gone bad - if it is common enough to replace it.

Do you have a part number? Unlikely that I have it, but I might be able to steer you to one.

It is a Pixelworks PW318C-30L
~600 Ball

Curious if some of these processors have EEPROM data that ties them to a specific system/serial#/part family/etc.
It would not surprise me at all if there was some effort in security from Sony.

[G0MJW]

In part 2, Dave takes it apart fault finds it, spends several late nights and then discovers his broken HDMI cable.

Mike

[jellytot]

Hi Dave. Do you still have that 65 inch telly? Have a look at the XD engine ic or ram chips surrounding it top left of mainboard. Try heat,  freeze  or apply pressure on it and see if anything changes....could be bad solder bga here. worth a try...

[aqarwaen]

i just wonder how long it will take then dave finds any 8k tv from dumpster  .i mean chances are very low for this,..but maybe that building  where dave got his office/lab has got enough rich companys who can dump 8k tv into dumpster..