LG 42LK450 no sound or hdmi

[Bigredram87]

Hi guys I'm considering picking up my second broken tv to attempt to repair. You guys did a great job helping me fix my first. Anyways I want to see of this problem has been heard of or if it's most deffinately going to be a logic board replacement LG 42LK450. Has no hdmi sound or video . Component video works but still no sound. Thanks for any input

[newtothis]

Re: LG 42LK450 no sound or hdmi

I would point my finger at the mainboard as the HDMI wont work but component will. Hang fire and see what others think too though.

[Bigredram87]

Re: LG 42LK450 no sound or hdmi

Ok I'd love to fix it component level if possible Id love the experience

[newtothis]

Re: LG 42LK450 no sound or hdmi

Mainboards are not easy repairs unlike PSU's

[rawsy]

Re: LG 42LK450 no sound or hdmi

hello i have a very similar issue to the op. i managed to source a mainboard and the sound now works. i have found however my picture has very strange colour. i know that the reason for this is that the board i have is programmed for a 37lk450 and the not the 42lk450 i need. i have found how to get in the instart service menu but am beign asked for a password. please help i have spent a day messing around only to be defeated by a 4 digit number lol.

i have tried

0000
1234
0413
7777
8 7 4 1
8 7 4 3
8 8 7 8

many thanks

[multimeter]

Re: LG 42LK450 no sound or hdmi

hello i have a very similar issue to the op. i managed to source a mainboard and the sound now works. i have found however my picture has very strange colour. i know that the reason for this is that the board i have is programmed for a 37lk450 and the not the 42lk450 i need. i have found how to get in the instart service menu but am beign asked for a password. please help i have spent a day messing around only to be defeated by a 4 digit number lol.

i have tried

0000
1234
0413
7777
8 7 4 1
8 7 4 3
8 8 7 8

many thanks

try this for a reset,and then get into service menu,and set your screen size to 42", Hold MENU on TV and MENU on remote for around 10 seconds, then select the reset option

[rawsy]

Re: LG 42LK450 no sound or hdmi

thanks for responding. i was just about to post how i did it. the only way i could get n to the menu was buy programming a one4all remote i found the instructions herefor future reference.
all the other methods i tried would not work. none of the passwords would work so i updated the firmware and all of a sudden they worked. if anyone is to try this it isnt just a case of changing the screen size in the options all the other settings need to be changed too. its fairly easy though as the tool options are listed 1 - 5 and have a code next to them which denominate all of the settings. so just change them to what the origional board was set to and away you go.

thanks for trying to help , i managed to sort it after 7 hours of messing around.

[tibimakai]

Re: LG 42LK450 no sound or hdmi

I have installed the same 37LK450 board in a 42LV3500 TV and it works great, except the screen is upside down.
Did you see any setting in there, with that I could flip the screen?
I can't get to the service menu.
The LV3500 doesn't even has a Menu button on the TV itself, just Home, Enter, Input, Channel up/down and Volume up/down.
I'm scared to update the firmware, because it may not work with this screen. Which firmware should I use, the 37LK450 or the 42LV3500?
What would you do in my situation?

[budm]

Re: LG 42LK450 no sound or hdmi

@tibimakai, what is the screen model number, some panel has one control pin for the picture rotation.

[tibimakai]

Re: LG 42LK450 no sound or hdmi

OK, here is the panel model # T420HW08 V.1. It's an AUO panel.

[budm]

Re: LG 42LK450 no sound or hdmi

See page 10 pin 6

[tibimakai]

Re: LG 42LK450 no sound or hdmi

Wow, that is amazing find. Thank you for that.
Now, where is this located and how do I do that switch to GND?
It is between the T-Con board and thin panel board, or the LCD's thin board and panel?

[budm]

Re: LG 42LK450 no sound or hdmi

If you look at the details, it is the pin on the LVDS connector on the T-CON board, see pin 6 if it is High or low.

[tibimakai]

Re: LG 42LK450 no sound or hdmi

Pin 6 is low(0V).

[budm]

Re: LG 42LK450 no sound or hdmi

High (3.3V) = ROTATE ENABLE. is there cable connected to that pin 6?, if not, use 3.3V power supply (3AA may work) to feed that pin through 1K, if there is wire connected to that pin 6, you will have to cut it so it will allow the pin 6 to go HI.

[tibimakai]

Re: LG 42LK450 no sound or hdmi

There is no wire there.
On the T-Con I see a pass through(that is how you call those? looks like a tube rivet) going through the through hole, at those pins, I could solder a resistor to it.
The question is if it works, from where can I get a permanent 3.3V?

[budm]

Re: LG 42LK450 no sound or hdmi

They are called VIAS, I am sure there are 3.3V power supply on the T-CON, just have to look for 3.3V regulator IC.

[tibimakai]

Re: LG 42LK450 no sound or hdmi

I have managed to solder a 1K resistor to via 6 and applied 3.3V to it, but nothing happened.
I have a ribbon cable and not wires.
The datasheet is for V 5.0 and mine is V 1.0, the version 5 could have different pinout, no? I can't find a V 1.0 datasheet.

[tibimakai]

Re: LG 42LK450 no sound or hdmi

Actually, I have just found it and it's the same:
http://wenku.baidu.com/view/e4db3926482fb4daa58d4b83

[tibimakai]

Re: LG 42LK450 no sound or hdmi

Pin #6 is grounded right now and it's no point in supplying it with 3.3V, no?