I have an LG 37LC2D that has no sound and picks up no channels. The HDMI works, but no sound from it either. The picture is great, and all the menu functions are working well. Any ideas on what could cause both of these to stop working? Any help is much appreciated!
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Re: LG 37LC2D No Sound, and No Channels
Seen it before - low 3.4V on PSU. Mine had loss of sound (everything), no Freeview channels (always "Weak signal"), intermittent HDMI, and intermittent RC control and side-buttons. Everything else worked so it had to be something common to these.
My fix was to replace the PSU (cost £30) because I was a bit stupid and burnt out a few other compoennts
but you might be able to replace a bad cap which sometimes goes bad.
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Re: LG 37LC2D No Sound, and No Channels
None of the caps look bad, so should I just replace all of them on the PSU?Comment
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Re: LG 37LC2D No Sound, and No Channels
First, do you have a digital multimeter?Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
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Re: LG 37LC2D No Sound, and No Channels
Yes, I have one.Comment
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Re: LG 37LC2D No Sound, and No Channels
Good... Can you post some pictures of the power supply, especially around the connectors going to the main boards. It's been a few months since I fixed mine so I can't remember where the 3.4V is output, but it is labelled.
BTW, are you in the UK or US or another country? The US version of the 37LC2D is very different to the UK version, although the PSU is the same.Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
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Re: LG 37LC2D No Sound, and No Channels
I'm in the US. I'll post some pics here in a min.Comment
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Re: LG 37LC2D No Sound, and No Channels
Here are two views of it. With and without the connectors.Attached FilesComment
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Re: LG 37LC2D No Sound, and No Channels
Thanks for those nice, clear pictures.
I've highlighted in RED some test points for 3.4V. (There are several.) I've also highlighted a connector in green.
Please set your meter to DC 20V if it is manually ranging, otherwise if it is autoranging use normal DC volts.
Then, place the black probe in the chassis of the TV.
Plug the TV in and put it into standby mode.
Check the 3.4V voltage on the red pins using the red probe. You should get from 3.2V to 3.4V.
Then turn it on (exit standby mode) and re-test 3.4V.
Turn off and unplug the TV.
Then, unplug the green connector which provides power to some audio processing logic, which is the most power hungry part of this TV.
Repeat the above 3.4V test with this connector unplugged; if 3.4V substantially rises the problem is probably with the 3.4V supply.
Note the above test MAY only be applicable for the UK version as that has a separate AV board with audio and a HDMI/video/scaler/DVB-T board.Attached FilesPlease do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
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Re: LG 37LC2D No Sound, and No Channels
Okay, I tested with the power on, and it reads 3.41. With the "green" unplugged, it reads 3.46. I do not have the remote to try standby mode. The green caps are definitely Samxon GF series caps.Comment
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Re: LG 37LC2D No Sound, and No Channels
Hmm. That is strange, because a low 3.4V voltage would normally cause the problem, as it has been on my set and a few other users.
There is also a 19V supply on this board and a 6V supply. Both use a similar circuit to the 3.4V so potentially they could go bad too. Can you please test both of these and see if they are reasonably close?Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
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Re: LG 37LC2D No Sound, and No Channels
The connector on the left was at 3.31, and the connector in the middle was at 3.41. I only tested the 3.4 points. Also the speakers have been making a loud static sound just since I've been testing the power board.Comment
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Re: LG 37LC2D No Sound, and No Channels
That is another symptom of the low 3.4V (crackling sound), but it's possible the US version is different, maybe moving the 3.4V power to the main boards.
On the connector can you see the markings for 6V and 19V?Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
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Re: LG 37LC2D No Sound, and No Channels
Yes, I see those.Comment
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Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
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Re: LG 37LC2D No Sound, and No Channels
All the points were reading
6v-11.78
12v-11.83
19v-18.8Comment
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Re: LG 37LC2D No Sound, and No Channels
That is a very high 6V; it could be causing a problem, though I'd normally expect something REALLY bad to happen if it was nearly double the voltage. Like smoke and flames from parts
. Double and triple check that is reading correctly.
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Re: LG 37LC2D No Sound, and No Channels
Its still reading at 11.78 for the 6v. I unplugged the middle connection, and then it dropped to 10.98, but that is still almost double. Its crazy because the tv works as far as picture goes. It just has no sound nor channels.Comment
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Re: LG 37LC2D No Sound, and No Channels
When you unplug that connection does 12V drop similarly?Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
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