LG 42LD560 TV problem

**sdrambo** · 21-03-17, 05:00 PM

My neighbours TV comes on with the LG logo and a clock face with -- -- on the screen. Nothing further happens. Would appreciate any help you can give. I have not split it apart as at least it is sort of starting, this to me meant that PSU could be OK. I have repaired switch mode power supplies with bulging caps before so have the basic tools. ie Soldering iron and multimeter. Thank you

**sdrambo** · 22-03-17, 10:57 AM

Are there any forum members servicing the Sunshine Coast area, please pm me. Thanks

**tristen** · 22-03-17, 12:01 PM

If it's any help, you will find a service manual at the jordansmanuals website .

**loopyloo** · 22-03-17, 04:33 PM

It will more than likely be the video chip on the main board.

**sdrambo** · 22-03-17, 07:53 PM

Well YouTube search suggested cooking the motherboard at 200C for 10 minutes in the oven(). What have I got to lose. And it worked, the TV fired up. For how long? well we shall see.

**bob_m_54** · 23-03-17, 11:34 AM

Ya gotta love Youtube eh? LOL. I wonder if it actually reflowed solder under one of the chips, or got a dying electrolytic cap to start working again. Was the board completely cooled down by the time it was switched on? If it dies again, try playing some hot air from a hair drier over any electrolytic caps on the board, or even other components, and see if it comes good again. Try and be selective, so that you can localise the component/s causing the problem. Cold or cool air from an air compressor on low pressure can also help to find similar faults.

**sdrambo** · 23-03-17, 06:31 PM

Originally Posted by bob_m_54

Ya gotta love Youtube eh? LOL. I wonder if it actually reflowed solder under one of the chips, or got a dying electrolytic cap to start working again. Was the board completely cooled down by the time it was switched on? If it dies again, try playing some hot air from a hair drier over any electrolytic caps on the board, or even other components, and see if it comes good again. Try and be selective, so that you can localise the component/s causing the problem. Cold or cool air from an air compressor on low pressure can also help to find similar faults.

A couple of forums had the same solution. 200c is not going to reflow solder AFAIK. The board was cool before switch on. The TV is still going 24 hours later. I have no faith in this technique being a fix however, although it has worked temporarily at least for quite a few people, if you can believe the posts!

**bob_m_54** · 23-03-17, 10:01 PM

Eutectic solder (63-37) melts at 183degC, but for 10 mins, it's hard to say if the solder would reflow or not. See how it goes I guess.

**sdrambo** · 24-03-17, 08:21 PM

Originally Posted by bob_m_54

Eutectic solder (63-37) melts at 183degC, but for 10 mins, it's hard to say if the solder would reflow or not. See how it goes I guess.

That low I did not know that. I preheated the oven to 200 and then put the board in on a thin piece of cardboard, the oven light came back on and stayed on till the timer went off. Meaning its unlikely that the temp got to 200. TV is still working BTW.

**tristen** · 24-03-17, 10:15 PM

Originally Posted by sdrambo

That low I did not know that. I preheated the oven to 200 and then put the board in on a thin piece of cardboard, the oven light came back on and stayed on till the timer went off. Meaning its unlikely that the temp got to 200. TV is still working BTW.

Actual oven temperature also depends on how accurate the thermostat is. ( I suspect not very accurate).

**loopyloo** · 24-03-17, 11:55 PM

The chip will often fail again if you don't use flux so if it does, go to Jaycar and buy a liquid flux pen (it releases the flux by briefly pressing the tip), use it around the chip until you have flooded underneath the chip with the flux, then leave it at least 10 mins to dry. Do your oven trick at say 230c and it should be good for a long time.

**aarty** · 04-04-17, 09:54 PM

Originally Posted by loopyloo

The chip will often fail again if you don't use flux so if it does, go to Jaycar and buy a liquid flux pen (it releases the flux by briefly pressing the tip), use it around the chip until you have flooded underneath the chip with the flux, then leave it at least 10 mins to dry. Do your oven trick at say 230c and it should be good for a long time.

I have the same issue with this TV set.
I reheated the main CPU on the main board and the unit worked for 5 days then packed up again.
I'm thinking now doing the flux as you described above and giving it another go with the hot air heat gun.

I hope it works longer.