Lg 42lf65 flashing red green light

[Ice203]

I've just had apart above TV and found one blown cap and faulty bridge rectifier. So replaced both and now TV red light flashes once and 4 green.
Anyone have any ideas what I can check next.

[Ice203]

Re: Lg 42lf65 flashing red green light

I'm getting 5v at the pwr. And when shorted I get 6.5v at the 6.5pin and 0 at the 3.4v on pin.

[tom66]

Re: Lg 42lf65 flashing red green light

Are you getting a power on signal from the main board? (Marked PS ON, or ON/OFF)

[Ice203]

Re: Lg 42lf65 flashing red green light

Yes 5v at the pwr pin

[tom66]

Re: Lg 42lf65 flashing red green light

So, that means the power board is faulty.
Got any pictures of it?

[Ice203]

Re: Lg 42lf65 flashing red green light

http://i989.photobucket.com/albums/a...oads/image.jpg
Won't let me add via attachments due to being on my phone

[tom66]

Re: Lg 42lf65 flashing red green light

Is that fuse near the big 450V caps OK?

[Ice203]

Re: Lg 42lf65 flashing red green light

Yeah tests ok.

[tom66]

Re: Lg 42lf65 flashing red green light

Ok, measure volts DC from each red point to the black recessed solder point, you may find you need to solder a wire to this point to make an accurate measurement. Use highest DC range. Expect around 380-400V when the power supply PWR signal is high (>2V)

Caution: High voltage! Do not touch any part of the primary side which you are testing while it is powered on! Discharge 450V caps before soldering. I recommend someone should watch you whenever you do primary side/high voltage testing.

[Ice203]

Re: Lg 42lf65 flashing red green light

I just plugged in to test what u said and the dam things working. Very weird.
So turned it off and bk on and I won't come back on.

[Ice203]

Re: Lg 42lf65 flashing red green light

Getting 874 at those points

[tom66]

Re: Lg 42lf65 flashing red green light

Check again, as that is definitely not correct.
If still high: Check meter is on DC range, and check meter battery is fresh.

[Ice203]

Re: Lg 42lf65 flashing red green light

What a noob. Had on wrong setting. Can tell I'm new to this.
This time I got 397.

[tom66]

Re: Lg 42lf65 flashing red green light

Good, that's correct then. PFC circuit is working (boosting 320VDC to 397VDC) and power board is registering power on signal from main board.

I take it's 397V both sides?

What's the part number of that device mounted on the heatsink just left and to the top of that fuse you were measuring from?

[Ice203]

Re: Lg 42lf65 flashing red green light

Pqnk65zfp
Gkdkn. Vw
Chn 710

I could be wrong as very hard to see.

[tom66]

Re: Lg 42lf65 flashing red green light

Just a MOSFET.
I'm going to need a pic of the board under that MOSFET.
Can you upload it to this site using Manage Attachments feature - tinypic is horrible.

[Ice203]

Re: Lg 42lf65 flashing red green light

turned it on this morning and it working fine, turned it off and again wont turn on, green light just flashes

[tom66]

Re: Lg 42lf65 flashing red green light

Sorry - I meant the underside, the green side of the board.

[Ice203]

Re: Lg 42lf65 flashing red green light

[tom66]

Re: Lg 42lf65 flashing red green light

Is there any way you could get a higher resolution - I need to be able to see the small circuit components.
And please use Manage Attachments or imgur if you have to use a file hosting site (Photobucket deletes files often)