LG 42ld450 repair tips

[shopyd]

hello every one

i need help on repairing this tv board . P42-10LF Board EAX61124201/15 ver 1.2 t the Tv 42ld450 by LG
i disasemled the board and start it fron jumpering the conector and then started the ccfl this way too .but the problem is that it lights for 2-3 seconds and go dark .if i disconect the power and conect again it is doing the same.i checked all the component with the right instruments and did not find any defected components.

is some one deal this problem and have any sagestions.

thanks

 

[Turnip]

Hi,

Note power supply includes inverter. Would think that if caps are not bulging, it might be a duff CCFL issue, but unsure as to go about testing them as guess they're all connected in parallel so can't check individual tubes without dismantling screen, maybe - Good Luck - Chris.

Notice several P/I boards for your model on Ebay.

[shopyd]

thanks
i tested the inverter with an other ccfl that i have out of the tv and the symptom is the same.

i changed all the caps and did not solve the isue.

do not know what to check more?

[Turnip]

Hi,

Guess if you've checked with another screen, as you seem to have, why not replace the Power/Inverter, as they're cheap on Ebay at this moment - Chris.

[shopyd]

yes this is what i will do at the last option

i see that aliexpress sell this boards for 40$ including shipping (used)

i wonder if to buy them or look for new ones?

[Turnip]

Hi There,

Don't you have Ebay where boards are OK or refundable ? - Chris

[shopyd]

 hi chris

yes i do have but i buy from aliexpres and for your knoladge they have a similar system of refund like ebay
your money is safe there if somthing wrong you can open a dispute and discuse with the seller the isue

but i think i will buy a new one not a used .it is beter for the long way using the TV

 

[downunder]

Hi shopyd,

I assume you need to start this tv by connecting PS-ON to the Standby Volts. Is it not possible then that it's

the Main board that's faulty.....not supplying PS-ON to activate the power supply. Have you stuck a meter

on the PS-ON pin to see it remains high after power-on?               Bruce

[shopyd]

thanks bruce

i did this by jumpering the standby pin and the pson on the power suply and jumpered the standby pin and the inverter on .i disconected the main board and do it only on the power board .but when i conect the power to the board the ccfl light for few seconds and shut down.so i assume the problem is the inverter.

what you think

david

[downunder]

OK. I think I understand now. It definitely appears to be the I/P board that's faulty. Unfortunately

I have never diagnosed one of these to component level, so I can't advise which component may

be causing it.            Bruce

[OldLes]

You say the CCFL tubes come on for 2-3 seconds. ALL of them?
OK, I know it is LG, not Sharp, but my experiance with the latter has been lockout due to failed tubes, where just one, or maybe more fail to light.
I bought a tester, but they all test OK, though they are not quite right.
Just a thought.
Les.

[Turnip]

Hi Les,

Remember your Sharp well, as I had one with a similar problem - sorted by hard wiring every tube to the inverter panel, as edge connector/panel print - mostly cremated.

Had a look at the LG Power/Inverter board on the Flea, and noticed just two connections to the backlights.

Had similar screen in a while ago and discovered that tubes were connected in parallel. My tube tester can only manage one tube at a time, so guess it's a matter of taking the screen apart to check, if keen.

Other thought is - Wonder if the P/I could notice if just a tube or two wasn't firing up when perhaps the other 10 were - All fun - Chris.