Lg 47LH40-UA

[oldhippie100]

Re: Lg 47LH40-UA

ok got ya..thanks

[rickem3]

Re: Lg 47LH40-UA

I do not believe you will find them in local store since these are used mainly in high voltage circuit such as the backlights inverter. Mouser and Digikey, or EBAY will be the place to look. I will look at electronics recycle place to see if I can find them on old boards I collect.
So you need the 33 and 54, one each? If I find them this Sat I can mail them to you since they will fit into regular envelope.

I'm new here and have the same burnt 33 & 54. Hard to find them.

[rickem3]

Re: Lg 47LH40-UA

I'm so thankful this fix worked for me. Again thanks you.

[Larry_Ellison]

Re: Lg 47LH40-UA

Good Morning,

Can't make it out and can't find a spec on this board. Can anyone tell me the value of D605? It is located near the red circle in the first series of images.

Thank you.

[shawn84d]

Re: Lg 47LH40-UA

hi everyone i had the same problem as this but i have a lg 47LF11 i changed the 2 caps i now get a full picture and sound but the screen flashes about 3 times then the tv will shutoff has anyone had this issue before

[shawn84d]

Re: Lg 47LH40-UA

here is a pic of my board same as the others but rev 1.4 anyway my issue is i am getting 64.0 v from the yellow box and the 2 black disc caps get hot i was going to chance those as well but wanted to wait to order more parts so im just wanting to know if anyone has had issues with the box or not and where can i find one from

[budm]

Re: Lg 47LH40-UA

here is a pic of my board same as the others but rev 1.4 anyway my issue is i am getting 64.0 v from the yellow box and the 2 black disc caps get hot i was going to chance those as well but wanted to wait to order more parts so im just wanting to know if anyone has had issues with the box or not and where can i find one from

What GND point did you use to get the reading of 64V from the YELLOW BOX which by the way is the PFC INDUCTOR for producing boosted Voltage to run the main power supply and inverter circuits.
You should see >360VDC between the two legs of the main filter caps when TV is turned on.
Did you replace those two blue ballast caps?

[shawn84d]

Re: Lg 47LH40-UA

Ok I re tested the PFC INDUCTOR I'm getting 170dc v in standby when I power the tv on it goes down to 111 dc v also the 2 black temperature thermistor (Dsc 2.5d-15) are getting realy hot there is a faint buzzing sound when the power goes on I think it is from the PFC INDUCTOR

[budm]

Re: Lg 47LH40-UA

Ok I re tested the PFC INDUCTOR I'm getting 170dc v in standby when I power the tv on it goes down to 111 dc v also the 2 black temperature thermistor (Dsc 2.5d-15) are getting realy hot there is a faint buzzing sound when the power goes on I think it is from the PFC INDUCTOR

Are you measuring the DCV on the inductor? You need to test the DCV between the two legs of the main filter cap.
http://assets.shopjimmy.com/media/ca...ay57681601.jpg
Shopjimmy does not have picture of bottom side so you nee to provide us one with really well focused so we can easily see the traces.

[shawn84d]

Re: Lg 47LH40-UA

pics

[budm]

Re: Lg 47LH40-UA

OK, those 2 thermistors are connected in series to feed the PFC Voltage booster circuit and there is no bypass relay and as they get warm the resistance should go down to reduce the power dissipation.
So we need to find out if the PFC Voltage is working or not first.
Also you circled those two blue ballast caps, did you replace them?

[shawn84d]

Re: Lg 47LH40-UA

OK, those 2 thermistors are connected in series to feed the PFC Voltage booster circuit and there is no bypass relay and as they get warm the resistance should go down to reduce the power dissipation.
So we need to find out if the PFC Voltage is working or not first.
Also you circled those two blue ballast caps, did you replace them?

Yes I did replace the 2 blue caps the one was burnt that was the first thing I replaced I will check the pic voltage tomorrow

[shawn84d]

Re: Lg 47LH40-UA

Not sure where to go from here but now my tv won't power up at all I'm getting 120 + v through out the board

[newtothis]

Re: Lg 47LH40-UA

is that the voltage at the main cap?

We need to know this voltage, budm has asked for it a couple of times already

[budm]

Re: Lg 47LH40-UA

And I still do not get the answer as to what GND ref point is used for the measurement.
I just about had enough asking the same question over and over again, it has been happening a lot lately with lots of people I am trying help.
I am really getting really tired of it.

[newtothis]

Re: Lg 47LH40-UA

Yes I have noticed a lot of people who don't answer and come back with more questions and their own theories instead of following what is being asked.

[shawn84d]

Re: Lg 47LH40-UA

i was using a couple main one was the screw hole on the main board marked pg105 if thats not it where is the best gnd point should i use

[pigpen007]

Re: Lg 47LH40-UA

Removing both c402 and c407 caps and placing 100pf cap instead works.
My c407 was burnt to a crisp and it seemed smaller than the 33pf cap in parallel to it (side note that my 33pf is in the c402 spot). So I'm assuming that my c407 is a 22pf cap, unlike the 54pf which i'm seeing posted here.
None the less, I found a 100 pf 6kv cap locally for $1.50CAD and removed the 33pf.
Seems to be working fine. I've since ordered a few 22pf and 10pf caps if something doesnt feel right.

[topgun]

Re: Lg 47LH40-UA

I replaced c402 and c407 with 2 - 27pf and 1 - 33pf, both from Mouser.com. Soldered the legs of one of the 27pf to the other and then soldered to the board. Seems to be working good. I know this is an old post but this old unit is still working good.

[nomoresonys]

Re: Lg 47LH40-UA

Indeed, they made the ccfl tvs much better than the led and oleds that constantly have problems or are made to break right after warranty.