Author Topic: LG 42LW450U  (Read 1378 times)

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EVILMRB

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LG 42LW450U
« on: November 03, 2018,21:44:35 »
Hi this tv is on standby and when I press the remote the standby led flashes a couple of times really slow then the led goes blue then a click can be heard from the back and the led goes straight back to red. I tested the voltages on the input from the mainboard and I get 12v and 3.5v as well as the 24v but the pin that says PWR-ON 24v reads at 3.4v and when I press the remote the voltage on that pin goes to zero then back to 3.4v. I have heard that these lg tvs have a problem with the mainboard and putting them in the oven.
I have put some pictures up to view

PSU Model No: EAX62865401/8   REV1/0

MAINBOARD Model No: EAX64113202 (0)

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LG 42LW450U
« on: November 03, 2018,21:44:35 »

jordan

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Re: LG 42LW450U
« Reply #1 on: November 04, 2018,02:10:41 »
Check coil L407 near the power connector, under the glue, on main board, for breaks.
Greeting from Slovenia
Jordan Čebron

downunder

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Re: LG 42LW450U
« Reply #2 on: November 04, 2018,05:35:24 »

That connector. P201 (on the power supply) that feeds the main board has 2 rows of pins, the ones you can see at the top of the socket, and a row below that you have to access from the back holes in the plug. So you're reading PWR-ON correctly, but 24V is the pin below.

Of most interest is the pin designated DRV-ON, which is the backlight-on signal, again 3.4V approx., which I suspect you'll find missing. The LW series all seem to fall down in this respect. A cook-up in the oven will likely sort it (bad ball joints under the micro) and on your model the heat-sink on the micro is just held on but a bit of silastic at the sides. One I cooked didn't respond, so I put a weight on the heat-sink and tried again, but still no luck.

Those that do recover only last about 5 months, and the customer goes head-hunting for guess who.                      Bruce

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Re: LG 42LW450U
« Reply #2 on: November 04, 2018,05:35:24 »

EVILMRB

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Re: LG 42LW450U
« Reply #3 on: November 04, 2018,12:09:13 »
Will I be able to use my rework station instead of oven.

Turnip

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Re: LG 42LW450U
« Reply #4 on: November 04, 2018,12:50:32 »
Hi EVILMRB,

Some folks use a preheater and a blast of hot air from the top. On the other hand the oven set to 200C for ten minutes usually sorts the problem without melting anything.

Admit had to replace a couple of melted Scart sockets before I used an oven thermometer.

When it gets to temperature, slip in the board. Turn the heating off, just using the fan to circulate heat. Pretty successful to date - Chris.

EVILMRB

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Re: LG 42LW450U
« Reply #5 on: November 04, 2018,14:42:43 »
Thanks for that, will try once I buy a thermometer. Will post results.

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Re: LG 42LW450U
« Reply #5 on: November 04, 2018,14:42:43 »

EVILMRB

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Re: LG 42LW450U
« Reply #6 on: November 04, 2018,15:25:46 »
To Jordan you was right, the fault was the L407 coil had a dry just under the glue resolderd tested for more drys in that area switched on all working. Big thank you to all who advised me but especially Jordan.

jordan

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Re: LG 42LW450U
« Reply #7 on: November 05, 2018,02:50:35 »
 :08:
Greeting from Slovenia
Jordan Čebron

Wirdy

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Re: LG 42LW450U
« Reply #8 on: October 18, 2019,06:49:38 »
Searched for a fix to this fault & I have registered purely to say thank you for this thread & in particular to Jordan, his advice above to look at L407 was my exact fault (cracked dry joint). I'd never have noticed it without the tip, so thank you very much.

 

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