Mulja tv repair portal
Equipment Repairs => LCD TV forum => Topic started by: EVILMRB on November 03, 2018,21:44:35
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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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Check coil L407 near the power connector, under the glue, on main board, for breaks.
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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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Will I be able to use my rework station instead of oven.
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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.
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Thanks for that, will try once I buy a thermometer. Will post results.
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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.
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:08:
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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.