LG TV MainBoard Solder Reflow
Whilst most issues relating to LCD TV sets not turning on tend to be caused by faulty capacitors on the power board, it seems that a lot of LG LCD TVs are also suffering from cold solder joins on the mainboard, which can lead to:
- Refusing to turn on
- Turning on then turning off after a short amount of time
- Getting stuck on the LG Logo boot screen
- HDMI Inputs not working
- AV Inputs not working
- And lots of other random glitches.....
If you are out of warranty and want to attempt a repair yourself, then continue reading for a possible fix:
Please only attempt this technique with an electric convection oven, microwaves, gas ovens or any other heat source will be a fire hazard, and will permanently ruin your board.
- Unplug the TV, and lay it down on a nice soft surface so that the screen can not be damaged or cracked whilst you work on the set.
- Remove the screws in the back of the TV, so that you can remove the rear plastic cover of the set.
- Identify the Mainboard - this will be the board that typically has HDMI inputs, Composite, Scart inputs. (Now is a good time to take a photo of the back of the set, for later reference)
- Gently remove all of the cables that are connected to the Mainboard - most of the connectors will just unplug - in some cases you will need to lift up the plastic latch on the ribbon connectors before you can slide the ribbon cables.
- Remove the screws holding the mainboard to the back of the TV set - and remove the mainboard from the set completely. In some cases the main board will be attached to a small piece of plastic housing, remove this too.
- Preheat your oven to 385 °F (196 °C) - if you are not sure that your oven is accurate it's probably worthwhile to get a cheap thermometer to check. Make sure the oven is well ventilated, open your windows, as the solder and board will smell a little bit.
- Place the board face up on something nonmetallic, balanced on an upturned ceramic oven pan is fine. (IT MUST BE NON METALLIC, otherwise your board will get stuck)
- Place into the oven on the middle shelf, and leave to cook for 10 minutes.
- Turn off the oven, and leave to cool - do not move or bump the board at this stage, as you risk permanently damaging the board. You may open the oven door slightly to speed up the cooling process.
- Once cooled you are now ready to install back into the set.
Please note that the above technique will void any warranty you have, you are essentially heating the board up to a temperature where all of the solder on the board becomes liquid again, and any cold/broken joins will be reformed.
Reflow Technique Video