No power LG 32LH20R

[sonyv1]

Hi,
Need some help here. I' been searching around and seem most LCD TV that have no power issue is due to capacitors problems. But mine is different, as you can see mine are all in good shape and no leaking as well.
The power board seem to be ok. I'm lost now, thinking of replacing the board which cost $100.

[randtek]

Re: No power LG 32LH20R

Is it completely dead, or is the Power LED Lit red? If the LED is not lit, check your power board to make sure it is putting out standby voltage, usually 3.3 or 5 volts. You can check this at the big power supply connector with lots of wires. A better photo would make it easier for someone to help you. Get a close up, so the numbers on the board can be read if possible.

[tom66]

Re: No power LG 32LH20R

Test the output voltages. These capacitors can fail without bulging.

[selldoor]

Re: No power LG 32LH20R

Hi - Welcome- I do not know much in the way of advising you re the tv but I can help you get help.
You need to post some information about yourself - electronic knowledge/soldering skills etc. How you came by the set -it makes a difference if you found it in a field or owned it for 2 years. Also what tools do you have, soldering iron /multimeter etc .Can you update your profile with at least the country you are in so that when it comes to buying parts you can be best advised. Read some of the other longer threads and see what other have done.

Your picture is not really good enough we need to be able to read the part numbers on the board and you need to post a picture of the other side and ideally an overall picture of the back of the set with the boards in place.

"But mine is different, as you can see mine are all in good shape and no leaking as well. "

If you had read anything much on this forum you would already know that a good looking capacitor is never a guarantee of its performance.

We need a full story as we cannot see what is happening. When you switch on do any lights come on - how long for- do the flash, does the screen flash at all, is there any sound, hum hiss crackle etc - have you tried with any input dvd/ pc.
Tell us what you have tried so far. Have you ever seen it working. Can you find a schematic for the Tv and or the power supply.

Have you checked the fuse?

[sonyv1]

Re: No power LG 32LH20R

Hi, thanks for replying back. There is no power led on at all when power up. Have try taken out the power board, no burning mark on the bottom surfare. The fuses are working fine.
I can easily get capacitors and replacement parts since I live in Singapore.
Might as well change the capacitors since it quite cheap in my country.
Will show more detail photos later on.

[tom66]

Re: No power LG 32LH20R

Hi, thanks for replying back. There is no power led on at all when power up. Have try taken out the power board, no burning mark on the bottom surfare. The fuses are working fine.
I can easily get capacitors and replacement parts since I live in Singapore.
Might as well change the capacitors since it quite cheap in my country.
Will show more detail photos later on.

Just make sure they are quality capacitors. Cheap market place ones might work for a few months then die again. Would highly recommend a low-ESR Rubycon, Chemicon, Nichicon, or Panasonic capacitor.

However, your problem is most likely a problem with another component such as a shorted diode. Do you have a digital multimeter?

[sonyv1]

Re: No power LG 32LH20R

You mention about the diode, is it the one nearest to the transfomer? When I measure with multimeter, there no beep sound but my mulitmeter is low in battery.

[retiredcaps]

Re: No power LG 32LH20R

Arrrrgghhh. Epic fail on the inline pictures. I'm out of this thread.

Reasons.

https://www.badcaps.net/forum/showpo...5&postcount=12

[tom66]

Re: No power LG 32LH20R

No; there are diodes on the secondary side. Can you post a picture of the bottom of your power supply (not inline!)

Also, it would be highly recommended to change the battery as a low battery may lead to inaccurate readings.

[sonyv1]

Re: No power LG 32LH20R

ok, need to resize the photo.

[selldoor]

Re: No power LG 32LH20R

Ok- First thing get your meter sorted out. Second or maybe first we need to get Retiredcaps back onside. Your pictures are posted correctly but the content is not good.
The reverse sides I think will do but we ask for you not to use flash. It still needs a full picture of the front of the board, in focus, so we can read the numbers. Close ups only required if you have spotted a potential problem or we ask for them. (I dont think Randtek meant you to take a close up of parts of the board he meant get close to the board to take a picture of the full board.) We also need pictures of the Main board.
You need to try and answer all the questions that are asked. Both Randtek and Tom66 asked you to test the output voltages.TAKE CARE AS PARTS OF THE BOARD WILL HAVE LETHAL VOLTAGES ( With the mains attached and switched on test the voltages at the connector which leads to the main board. Probably with your meter on 200vdc put one pin to a ground near the connector then check each pin of the connector ) You may have done that but you need to post what they are, in a table. for example:

Pin Designation actual

1 ........... gnd ........ 0
2 ........... 12v ...... 13.20
3.............. 5v ........ 3.36

Then do it again just to check they are nearly the same in case you have mixed up a pin.

Another test you can do VERY CAREFULLY is with the mains connected and your meter on 600v DC, test what voltages there are across the legs of the 2 large capacitors. I think Singapore is same mains as uk so reading should be around 320 voltsDC

When you originally said "The power board seem to be ok"was that just based on visual inspection?

[sonyv1]

Re: No power LG 32LH20R

Sorry for the bad photo, my room is full of light so this is the best what I can get. And yes I judge the board by only based on visual inspection. Have to replace the battery and ground the board first.

[selldoor]

Re: No power LG 32LH20R

Hi - thats a good picture. The voltages you are testing are on socket P201 ( Easy when I can read it) When I said "put one pin to ground" It just means on the board
In this case the metal tag surrounding the fixing hole in the corner labelled PG102.

Can you also say what is the make of the capacitors on this board.

[sonyv1]

Re: No power LG 32LH20R

Just tested all the zene diodes, found 2 zene diodes have 2 readings. While others have 1 reading which mean the other reading is 0 ohms. Are these 2 diodes faulty?
Circle A= 2 reading almost 0 ohm at 20k ohm test. 0.2 ohm at 2k ohm test.
Circle B= Both reading at higher ohm.

[tom66]

Re: No power LG 32LH20R

Before jumping to conclusions, it is best to test the output. If there is an output voltage that is stable and within tolerance, the power supply is likely okay. However, if those zeners truly measured 200 ohms they are dodgy, to say the least - they could be failed. If you are getting zero or very low outputs (1-2V on 5V for example) they could be the cause.

[sonyv1]

Re: No power LG 32LH20R

Thank guys, fix the problem and save big bucks.
Its the diodes circle B 5252 that cause the problem.
Spend less than $1 and buy 2 piece of 5227 diodes Circle A and 2 piece of 5252 diodes Circle B.
Almost spend $100 for replacement of this power board, glad I found this web site
Thanks again.

[tom66]

Re: No power LG 32LH20R

Thank guys, fix the problem and save big bucks.
Its the diodes circle B 5252 that cause the problem.
Spend less than $1 and buy 2 piece of 5227 diodes Circle A and 2 piece of 5252 diodes Circle B.
Almost spend $100 for replacement of this power board, glad I found this web site
Thanks again.

Enjoy your TV!

[selldoor]

Re: No power LG 32LH20R

Well done - nice to hear a fix and not left wondering.

[duvanngoc]

Re: No power LG 32LH20R

Hi all,
I have same problem.
Here is detail: 2 parts have been exploded

i notice that i dont have experience in this field, so i want you let me know the name of those parts (have been explodeed) so that i can buy and replace them by myself, i think i can do it
anothe question: do you have the shematic for this one
The original image made by me but the quality is not good


Thank you.

[killian6pk]

Re: No power LG 32LH20R

Hi all,
I have same problem.
Here is detail: 2 parts have been exploded

i notice that i dont have experience in this field, so i want you let me know the name of those parts (have been explodeed) so that i can buy and replace them by myself, i think i can do it
anothe question: do you have the shematic for this one
The original image made by me but the quality is not good


Thank you.

The top green part is a Resistor. You need to tell us the color bands in order from left to right. From 1st color to gold band on right side in order. The component with 8 legs is going to be much harder. Take some alcohol and a cotton swab and gently try to clean off as much of the exploded material as you can. Then try to read the numbers from the top of that component. Report back to us all of this information. For informations sake you by by far do not have the same problem as the previous guy had. Tell us your background. Do you know how to solder. Do you have soldering equipment and a Digital Multi Meter? Do you know how to use the Meter?