LG 32LD490: dead then alive

Seems like a while since I last put a post up on here. Over the past few years I've posted something about my Mondeo when sorting it ready for its MOT each October. Unfortunately, over the past 12 months the rot had got the better of it and it fatally failed its last MOT. It's now scrapped and has been replaced with a Mk7.5 Fiesta ST Line. I've got some plans for that next Spring and no doubt will be making some posts on here about that.

Anyway, on to tonight's project. I was asked to look at this LG TV.

I'm not sure how old it is but when powered up presented with a solid red stand-by light. The TV was otherwise dead, though, and could not be switched on. First thoughts were the caps on the power board but they all looked OK. The ones I could get to with my ESR meter were fine. I also checked the diodes on the power board which were all good. Finally, appropriate voltages were present at the connection to the main board.

I therefore turned my attention to the main board, in particular the BGA chips. In this TV, the two chips both have fairly large heatsinks so I wondered whether a little hot air reflow might help things.

In order to do that I had to remove the heatsinks which were on with sticky tape and hot-melt glue. The heatsinks came off easily enough with some warm air blown over them. I then ran some liquid flux under each chip and warmed them both to 200c for about five minutes.

Before refitting the heatsinks I checked whether the TV worked. On pressing the "on" button I could see that the LED backlight was now working and the standby light was now blue.

That was good enough for me. I cleaned the sticky tape from the back of the heatsinks and refitted them. Instead of more sticky tape I used some proper thermal paste and more hot glue to hold them in place.

And the TV now works. It's been on for a couple of hours playing some recorded TV programmes from a USB stick. Sorted ;)

More soon, no doubt....

D