8 of 9 people found the following review helpful
A good TV, but a TV w/o sound should not be shipped from the factory, failed 4-15-2014,
This review is from: LG INFINIA 47LE8500 47-Inch 1080p 120 Hz Full LED Slim LCD HDTV with Internet Applications (Electronics)
The TV failed April 15, 2014. I woke up that morning and found that the TV was turned on, LG logo appeared, but no picture and sound. As I could see logo, so back-light was OK. I have a service manual and necessary test equipment, so I poked around. All voltages from the power supply were correct per the spec. I checked outputs and waveforms of all DC-DC converters on the mainboard, everything was OK. All evidences indicated that I had a faulty mainboard (EBR66098201). I ordered the mainboard from LG part distributor (cost $240), put it in, and the TV worked again. My network log showed network activity between the TV and external site the night the TV failed, suggesting software update failure and bricking the TV.
I remembered a "software update" menu on the earlier software version on this TV. This menu was removed in the later version, the TV silently doing the software update by itself I supposed. My 27" CRT TV last for over 25 years. This $2,000 LG TV last for 4 years, so the rating for this TV and LG as a company is down to 1 star.
When I turned on the 47LE8500 I received, everything worked, except there was no sound from the speakers. After making sure that it was not the setup problem, I concluded that I received a defective unit. I was very upset, thinking about disassembling the stand re-packing the unit, obtaining the RMA, making an arrangement for pickup, and etc. This is a waste of time and money. The unit was shipped from Vanns. I have 14 days to return for a full refund, but I have to pay for shipping it back.
Thinking about the hassle of returning the unit, I thought I should open it up and see what I can do. I am an EE, done quite a bit of display designs from CRT to LCD. I know the manufacturing test process on product like this at the factory. It is unusual that a unit w/o sound could have passed without noticed. The unit w/o sound could have caused by intermittent connection that happened to be OK when it was at the factory, but became loose connection after that. With that in mind, I decided to open the back cover and look.
From what I saw, the 47LE8500 was very well designed. The main board is where nearly all external connectors are mounted. There are only 2 or 3 board assemblies and minimum wiring. The power supply, the most vunerable module in any electronic appliance, was well designed and thin. The only thing I don't like is that the power supply uses no-name cheap 105C electrolytic capacitors (e-cap). Given the 100,000 hours LED life, these e-caps could fail 10 times or more sooner. Other than that, I am impressed with the design and engineering of this TV.
Based on my assumption above, I looked at audio system starting from the speakers . There are 4 of them, 2 for left and 2 for right. I discovered that one of the speaker terminals touched the aluminum chassis. Even though there is a plastic insulator on the terminal, I noticed a burn mark on the aluminum caused by arcing from speaker's terminal. I bent the terminal away from the aluminum chassis and reinstalled the insulator. Before turning it on, I traced the speaker wiring to the audio amplifier located on the main board. The amplifier is a class-D amplifier (NTP-7000)using pulse width modulation (PWM) technique for better efficiency. I felt much better knowing that this kind of amplifier has internal output short circuit protection. The chip should not have been damaged by the short circuit I discovered. I put everything back together, turned it on, and voila...I had sound.
OK, here are my comments for all parties involved:
They did excellent job, TV arrived 3 days after ordering in good shape. They put the original LG box into another box, making it a double packing.
LG design Eng:
I would take away 1 star for giving a chance of short circuit to happen by design.
I would take away 4 stars for failing to catch this problem. Seeing the black mark, I knew that this problem was intermittent since it was at the factory.
The TV itself is of high quality and I love it. For the reflective front glass that many people don't like, I think this is a trade off of having a glass panel vs w/o glass. It is good if you can control light in your room, and could be annoying if you cannot.
As many other reviewers pointed out, there is a 0.5mm thick plastic attached to the front glass. I suspect that over 90% of owners do not notice this transparent plastic that covers the entire TV faceplate. It is not obvious for its purpose as it is not explained in the manual. I think it is for protecting the glass before reaching the end user. It seems like you could leave it on forever, but it could be an issue later when it get old, accumulating scratches, and becomes harder to remove. LG Customer Support had no clue, but suggested removing it. It is extremely difficult to reove. It took me 45 minutes to remove it. This is absolutely unacceptable. It is somehow the reflection of how LG works internally as an organization. Some groups are excellent, but some groups are so inferior. In this case, the 47LE8500 is their portrait. I hope that some bigwigs at LG will see my comments here and do something.
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Initial post: Apr 1, 2011 8:58:15 AM PDT
Last edited by the author on Apr 6, 2011 6:38:48 AM PDT
It is my understanding that the plastic film attached to the glass panel of the LE8500 is not intended to be removed.
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