LG 42LD560 PSU Problem? (stuck in standby)

[mostachio]

hoping you can help me out. I am a novice (but keen to learn!) so please dumb down stuff to the point a small furry animal could perhaps read it.

Trying to get a TV going for the garage and I have this faulty LG LCD so i'm hoping, with help, I can get it going without buying a replacement board.

Tools avail:
Multimeter
Soldering gear
Variable heat gun
Common sense around electricty
etc

TV: LG 42LD560
PSU: EAX61124201/15

Symptoms:
Will not boot. will not react to the remote. Is stuck in standby with its red light slowly pulsing.
Inverter Test Result: Working. When put into inverter test backlight stays on and does not go off.
Board looks physically OK, no domed caps and solder joins look fine.

Output voltages are incorrect (I can go through and test them again and post if needed) but very irregular, sometimes 0, sometimes I get weird voltages on *some* of the outputs (Like one 20V will test OK, one will test 3.5V). Power ON/OFF remains 0. I am not sure whether these voltages would be turned on once the TV turns on? Anyway there's a ebay repair kit that comes with all the capacitors (C220 C210 C218 C205 C217 C215 C208) beside the output to main plug. I do not have an ESD meter to test the caps. Could this be my issue? I don't mind doing a blanket change to check.

Thanks!!

Edit: Blanket changed all the capacitors (except 220uf 25v) between the volt regs & the output to main plug ($4-5 meh). No change in symptoms... Have not re-checked the DC outputs on main plug. TV still stuck in standby.

Should i just bite the bullet & buy a new PSU board?

[syaoran123]

Re: LG 42LD560 PSU Problem? (stuck in standby)

You have a heat gun which might come in handy. Use it on the large heatsink on the mainboard at 200C for 2 minutes and see if that works.

[CapLeaker]

Re: LG 42LD560 PSU Problem? (stuck in standby)

If PSon is 0 V DC, the PSU will not turn on. You have a main board problem.
If you force the PSU on manually you probably find that the PSU itself is working correctly.

[ReeceyBurger123]

Re: LG 42LD560 PSU Problem? (stuck in standby)

if pson is 0 v dc, the psu will not turn on. You have a main board problem.
If you force the psu on manually you probably find that the psu itself is working correctly.

+1

[mostachio]

Re: LG 42LD560 PSU Problem? (stuck in standby)

Oh praise you man, that fixed it. I'm guessing xbox style bga of the broadcom chip is dead. Thank god I didn't replace the PSU

I'll see how it goes & order a new main board if necessary.

P.S. For those that come across this,.. I may've done this at 250C for 2min 30... will keep this thread updated if/when it dies again.

Thank you syaoran123. Appreciated!

[CapLeaker]

Re: LG 42LD560 PSU Problem? (stuck in standby)

yw

[syaoran123]

Re: LG 42LD560 PSU Problem? (stuck in standby)

Oh praise you man, that fixed it. I'm guessing xbox style bga of the broadcom chip is dead. Thank god I didn't replace the PSU

I'll see how it goes & order a new main board if necessary.

P.S. For those that come across this,.. I may've done this at 250C for 2min 30... will keep this thread updated if/when it dies again.

Thank you syaoran123. Appreciated!

Indeed, it is a common probem with these models.

For a more permanent solution, you can use higher temperature. I use heatgun at 380C for 2-3 minutes to resolder the bga joints. Probably worth doing the same thing for the chip on the top left just incase. Make sure you keep the board flat and dont move it while its hot, or you could disturb the smd components.

[mostachio]

Re: LG 42LD560 PSU Problem? (stuck in standby)

Just saw this after having to repeat the process several times & looking up the number of the board from post to buy. Have tried a full 3min at 380C. TV works will keep updated. Cheers