LG 47LC7DF no power

[selldoor]

Re: LG 47LC7DF no power

Hi Pictures are not really good enough for troubleshooting
remember that is all we have to work from. They need to be as follows and should not have the edges cut off.
The only in focus picture is the one of the meter dial.

Examples of what is needed
https://www.badcaps.net/forum/attach...1&d=1290283049

https://www.badcaps.net/forum/attach...7&d=1280167246



Attached is a picture of a cable connector with the legend
beside it showing what pin does what. If you can post in focus pictures of yours we will talk through testing.

[selldoor]

Re: LG 47LC7DF no power

Ok Please try that test again - ALL the connectors should be connected and then the set plugged in and the power button pressed. What happens when you do that - any lights or sounds- what does the power led do?

Put your meter on volts DC20 and put the black lead on the ground screw in the right hand corner of Mr Bills picture.
Use the red probe and check along connector p200 each pin in turn.

[kzan]

Re: LG 47LC7DF no power

Power plugged in, pushing the power buttong does nothing, no lights on the front or anything.
I tried testing the connectors like selldoor suggested but getting no readings at all.

[multimeter]

Re: LG 47LC7DF no power

Power plugged in, pushing the power buttong does nothing, no lights on the front or anything.
I tried testing the connectors like selldoor suggested but getting no readings at all.

what line voltage is your house supply?,seems your pfc front end circuit may not be working,what is the maximum voltage your meter can take?.

you need to be measuring the large filter cap,tv plugged in ,and then tv turned on from standby,the voltage on the large cap should be around 3-4 times your line voltage when powerd on,if you get a good stable high voltage (say 300 ish volts)then your pfc circuit is working,if you have had a power outage or surge,then you should be checking varistors,your bridge,and if there are some,the transient diodes

[multimeter]

Re: LG 47LC7DF no power

looking at your meter in your pics,DONT measure filter cap,your meter only goes to 250v dc,you will blow your meter,you really should have a dmm at least to 1000v cat 2

[selldoor]

Re: LG 47LC7DF no power

looking at your meter in your pics,DONT measure filter cap,your meter only goes to 250v dc,you will blow your meter,you really should have a dmm at least to 1000v cat 2

Whilst the scale goes to 250v the selector shows 500ac or 500dc so he should be ok? I think he will need a bit more guidance.

Kzan- can you post a picture of the bottom of the board so we can afvise better how to measure at the capacitors. -If you can mark it with the
+ and - legs of the two BIG caps

[multimeter]

Re: LG 47LC7DF no power

Whilst the scale goes to 250v the selector shows 500ac or 500dc so he should be ok? I think he will need a bit more guidance.

Kzan- can you post a picture of the bottom of the board so we can afvise better how to measure at the capacitors. -If you can mark it with the
+ and - legs of the two BIG caps

i only seen the actual scale ,the pic is a bit fuzzy so wasnt sure,so rather than go ahead and nuke his meter,id rather be on the safe side

[kzan]

Re: LG 47LC7DF no power

I just noticed these 2 caps on the main board. Do they look like they are getting ready to burst? All the other caps are smooth and seemless, those 2 have lines going down towards the center like the top is getting ready to split open.

[multimeter]

Re: LG 47LC7DF no power

I just noticed these 2 caps on the main board. Do they look like they are getting ready to burst? All the other caps are smooth and seemless, those 2 have lines going down towards the center like the top is getting ready to split open.

those are fine ,visualy

[kzan]

Re: LG 47LC7DF no power

Whilst the scale goes to 250v the selector shows 500ac or 500dc so he should be ok? I think he will need a bit more guidance.

Kzan- can you post a picture of the bottom of the board so we can afvise better how to measure at the capacitors. -If you can mark it with the
+ and - legs of the two BIG caps

Bottom of the board meaning the back side of the board? Just trying to be clear on what pictures to post.

[multimeter]

Re: LG 47LC7DF no power

Bottom of the board meaning the back side of the board? Just trying to be clear on what pictures to post.

yes on the solder side,and mark your picture in relation to where the main filter caps are,you will be measuring these with power on,HIGH VOLTAGE so be carefull your probes dont short out,it may be awkward ,sometimes on the filter caps there is a little of there legs showing so you can put your probes in,sometimes you have to lift the psu to measure on the solder side,if you do have to lift the psu clear to take measurments ensure the board remains grounded,even if you just use croc clips and length of wire,normally the screws that fix the psu down act as the grounding point.

[Mongor62]

Re: LG 47LC7DF no power

Hello all i am new here so my posting abilities are very limited but i also have a LG 47LC7DF but i cannot find any post about my sub model number which is instead of it being 47LC7DF-UB mine is a 47LC7DF-UK and finding a service manual seems impossible. The reason why this is important is because my TV looks different from any other 46LC7DF that i see on the inside.

I don't mean to be high-jacking someone else post But like i said i am very limited.

My problem isn't total power loss because my TV will turn on and have sound just no picture but how i acquired my TV is something that is important and some of the reason why i will be asking a few questions.

I got my TV from a yard sale as a freebie if i bought something else. I was buying a vase anyways so it was only the cost of transport.

I have been reading and searching about this problem in other LCD TVs and just about all of them say its the power supply or the inverter board but as i am a novice i cannot locate the inverter board on this TV for the life of me.

I replaced the 2 large caps that were clearly blown (450v 150uf) & the fuse(250v 5a) that was blown near it and after starting it up again the problem remained and the fuse was blown again but how to trouble shoot this i don't quite know what my first step should be. I was thinking the Voltage Regulators but this once again i don't quite know because my lack of experience. I do own a Fluke 87 DMM but i and very new to it.

This TV appears to have been tinkered with a little before i opened it up so i have to ask is this TV missing something?

Any help is greatly appreciated and if this post is in the wrong spot or my questioning is out of order i apologize.

[JoeyJoe]

Re: LG 47LC7DF no power

That will be the first fuse to check. Make sure to unplug the TV first, the resistance reading should be less than one Ohm.
Any pictures of the boards?

Wouldn't the first fuse to check be in the plug? If it is a plug with a fuse.

[Mongor62]

Re: LG 47LC7DF no power

Please forgive my picture quality but i only had a phone and had to re-size them which degraded them. I am not too good with Photoshop but i drew some lines in to help direct attention to the areas of concern.

The picture of the left side is basically the same as the right but i put some outlines of where screw hole posts are where it looks like an inverter board could go but the problem is in the UB versions of my TV it has 4 boards and if you look at the picture there clearly isn't screw holes for all those boards

The picture of the Power Supply has the fuse missing because i took it out as it is blown. I circled the area of the fuse and the area where there is nothing plugged in.

The picture of the Main Board i have numbered 1 & 2, 1 is an open port where nothing is plugged in 2 is where i believe a chip/driver would be located.

The reason i showed the missing driver is to maybe ask if the power supply & main board are used in many different models and they only used the ports needed for this TV

checking to see if a fuse is blown is one of the things i do know how to do and it was well over 1 ohm and i doubled checked this with the lower fuse on the board which measured .2 and even triple checked it and turned on the buzzer part and it beeped for the lower and nothing for the upper (blown).

Power supply model = P/N : 2300KEG021A-F
Main board model = LA75A EAX38059704 (0) 071129 H.Y.H.

I didn't think anyone would respond so fast but i thank you for that and any help is always appreciated.

[budm]

Re: LG 47LC7DF no power

This may help:
http://www.shopjimmy.com/lg-eay36781...upply-unit.htm
http://www.shopjimmy.com/catalogsear.../?q=LG+47LC7DF
Your version uses power supply-inverter board combo instead of separate power supply and inverter board. There are more than one version of your TV model.

[Mongor62]

Re: LG 47LC7DF no power

This is good to hear and to hear it from you is good to i read some of you PDFs from a previous posts and i am getting it is just so overwhelming.

[joehezzer]

Re: LG 47LC7DF no power

Wouldn't the first fuse to check be in the plug? If it is a plug with a fuse.

lol i was thinking the same to

[Mongor62]

Re: LG 47LC7DF no power

I misread that did you say there is a fuse within the plug, meaning the cord? My cord looks like any old cord same as the one used for my computers PSU as a matter of fact.

[joehezzer]

Re: LG 47LC7DF no power

I misread that did you say there is a fuse within the plug, meaning the cord? My cord looks like any old cord same as the one used for my computers PSU as a matter of fact.

i forget your in the states lol i think all plugs in the uk have a fuse in

[joehezzer]

Re: LG 47LC7DF no power