LG 37LC2D No picture, believe bad power supply

[tom66]

Re: LG 37LC2D No picture, believe bad power supply

If it helps, I think the two problems (low 3.4V and freezing) are unrelated. The freezing to me sounds like a bad BGA joint on a processor somewhere, or on the RAM for the video processor.

[godzzila]

Re: LG 37LC2D No picture, believe bad power supply

Hm theres not any BGAs components.

[tom66]

Re: LG 37LC2D No picture, believe bad power supply

I noticed that now, so I guess that idea is out of the window.
Sorry, I don't really know where else to look, other than completely new main board.

[KingKong]

Re: LG 37LC2D No picture, believe bad power supply

i have to just say before that ive only soldered a few times and i have a lg 37lcd2 UE , i have been having issues for a few months with it turning off after 20-40 mins of being on or having it not even come on at all.. i opened it up and saw 1 capacitor was popped, i got the repair kit from ebay, had all the same capacitors, swapped out the bad one, put the new one in it (pic 1), put everything together, turned it on, and there was a high pitch whine/hum coming from the tv, left it on for 45 mins, didnt turn on..

So i then take it apart again and proceed to replace all 12 that came in the repair kit, got them all in and soldered , i think i did a ok job for a guy who was only in electronics class for a month and only learned basics..

So i get it put back together and i turn it on, there is NO high pitch whine or hums, but the tv did not come on. the green light flashes like 5-8 times and then goes solid green but the screen wont come on now at all..

after pics shows the ones replaced except the ones with rubber coating on it

Any ideas/help would be greatly appreciated

[KingKong]

Re: LG 37LC2D No picture, believe bad power supply

i couldn't edit my post but i just bought a new multimeter from ebay and it should be here soon to check the voltages

[Savage_steve]

Re: LG 37LC2D No picture, believe bad power supply

i have to just say before that ive only soldered a few times and i have a lg 37lcd2 UE , i have been having issues for a few months with it turning off after 20-40 mins of being on or having it not even come on at all.. i opened it up and saw 1 capacitor was popped, i got the repair kit from ebay, had all the same capacitors, swapped out the bad one, put the new one in it (pic 1), put everything together, turned it on, and there was a high pitch whine/hum coming from the tv, left it on for 45 mins, didnt turn on..

So i then take it apart again and proceed to replace all 12 that came in the repair kit, got them all in and soldered , i think i did a ok job for a guy who was only in electronics class for a month and only learned basics..

So i get it put back together and i turn it on, there is NO high pitch whine or hums, but the tv did not come on. the green light flashes like 5-8 times and then goes solid green but the screen wont come on now at all..

after pics shows the ones replaced except the ones with rubber coating on it

Any ideas/help would be greatly appreciated

What's funny is that I fixed a 37 LC2D yesterday I got from a buddy I go to hockey games with, likely using the same capacitor kit you got off of eBay. Mine didn't initially work and had to get help to sort it out.

I didn't see pics of your solder joints; but assume that they looked like my original efforts that maybe had some solder balls and looked dull where I didn't flow enough of the solder into the joints well enough to make enough contact. So determining that I sucked at soldering and was afraid of burning up the board and my kitchen, I have the luxury of working at a university with an engineering school and found that to be indeed the case.

If the caps wiggle on the board at all, then there is not enough solder for a proper contact and won't turn on. Heat up the wires enough with a good soldering iron (that can weld joints) and dab enough flux core solder so that it flow and becomes shiny. Then recheck the caps on the board for wiggle. It also helps to have a second person dab the solder where you want it too.

The main lesson I learned in my 'solder lesson' was to have a really good soldering iron that won't dissipate it's heat quickly when trying to flow solder and to wait for that electronic burning smell before you get scared of burning the board. Also the Electrical Engineer that helped me out also said that sometimes if you really 'suck' all of the original solder from the joint, it tends to require a bit more effort and patience to get enough solder in place at the joints to make contact. The first time I tried, I was scared of burning down my kitchen and trying to get everything done before my kids got home, so I wasn't patient enough with the solder. Hope this rookie experience helps to give you some reference to trying it again...

[DakotaKid]

Re: LG 37LC2D No picture, believe bad power supply

What's funny is that I fixed a 37 LC2D yesterday I got from a buddy I go to hockey games with, likely using the same capacitor kit you got off of eBay. Mine didn't initially work and had to get help to sort it out.

I didn't see pics of your solder joints; but assume that they looked like my original efforts that maybe had some solder balls and looked dull where I didn't flow enough of the solder into the joints well enough to make enough contact. So determining that I sucked at soldering and was afraid of burning up the board and my kitchen, I have the luxury of working at a university with an engineering school and found that to be indeed the case.

If the caps wiggle on the board at all, then there is not enough solder for a proper contact and won't turn on. Heat up the wires enough with a good soldering iron (that can weld joints) and dab enough flux core solder so that it flow and becomes shiny. Then recheck the caps on the board for wiggle. It also helps to have a second person dab the solder where you want it too.

The main lesson I learned in my 'solder lesson' was to have a really good soldering iron that won't dissipate it's heat quickly when trying to flow solder and to wait for that electronic burning smell before you get scared of burning the board. Also the Electrical Engineer that helped me out also said that sometimes if you really 'suck' all of the original solder from the joint, it tends to require a bit more effort and patience to get enough solder in place at the joints to make contact. The first time I tried, I was scared of burning down my kitchen and trying to get everything done before my kids got home, so I wasn't patient enough with the solder. Hope this rookie experience helps to give you some reference to trying it again...

It certainly sounds like you have a bad solder joint in one of the repaired caps. Also, check and make sure you got the polarity correct on all of the caps. The problem you are describing is the same indication as when the caps are bad so it is highly likely you just need to go back and double check everything and reflow your solder joints.

[birdog]

Re: LG 37LC2D No picture, believe bad power supply

Does anybody still come to this thread?

I had a bad PSU on a LG 37lc2d so I ordered a board from River Valley Electronics. They sent a board and the black and yellow box with the numbers LM-001 on it was melted. I installed it and when I plugged it in that part made a high pitched whining sound and the tv still did not work. I put the old board back in and the tv works for about ten minutes and then shuts off. Two capacitors are bulged on the old board. I tried calling River Valley but they are closed at 5pm. Does anybody know what that black and yellow box is in the PSU? Low voltage regulator?? Can I take that part off the old board and put it on the new board if they won't send me a good board? Thanks

[tom66]

Re: LG 37LC2D No picture, believe bad power supply

It's probably a transformer, I doubt it is melted, but there is probably something else wrong on the board.

[Porta Party]

Re: LG 37LC2D No picture, believe bad power supply

First, I would like to say thank you for all that I have learned from this forum so far, I have been browsing it for a few days and you all are very knowledgeable on this!!
I am having pretty much the same issue that has been going on this thread...turn on the TV Green light flashes several times and goes solid, backlight comes on, green light on main board comes on red led under power supply are comes on also... here are the readings i have measured.

P201 Measurements in ()
3.4V- (3.35v)
Gnd- (0v)
6V- (6.11v)
Dim- (5.13v)
Gnd- (0v)
st 5V- (5.15v)
BRI- ( .18v)
BRR- (5.12v)
IC- (5.03v)
GND- (0v)
st 5V- (5.15v)
on- (4.38v)
acd- (5.14v)

P202
Gnd- (0v)
12V- (11.71v)
Gnd- (0v)
3.4V- (3.07v)
Gnd- (0v)
6V- (6.11v)
Gnd- (0v)
Gnd- (0v)
19V- (18.82v)
19V- (18.82v)

P203
Gnd- (0v)
Gnd- (0v)
12V- (11.71v)
12V- (11.71v)
Gnd- (0v)
Gnd- (0v)
6V- (6.11v)
6V- (6.11v)
Gnd- (0v)
Gnd- (0v)
3.4V- (3.02v)
3.4V- (3.02v)

about me- I have been in the Air Force for 12 years this month, I have been working avionics systems during that time, mostly part swapping but has helped me with basic to advanced troubleshooting skills.
I have also been installing car stereo's as a hobby since I was 13 years old...I am now 32... I have soldering skills, in the Air Force one of the classes I teach is basic soldering... if there is anything else you need to know just ask.
Thanks in advance!

[ajshoe]

Re: LG 37LC2D No picture, believe bad power supply

post a pic of power supply.

[bev]

Re: LG 37LC2D No picture, believe bad power supply

Hi

[bev]

Re: LG 37LC2D No picture, believe bad power supply

Hi
Had same problem, buzz, no picture and 'no signal' , wouldn't recognised HDMI input. Changed caps in power supply, and now all works fine.

info for others
ref for caps on PCB nomininal value measured value off board
c201 and c202 3300uF 3220 -not replaced
c208 680 602
c210 680 602
c211 470 419
c228 1000 874
c238 470 441
c226 1000 922
Thanks everyone for posting solutions
Bev

[pecani]

Re: LG 37LC2D No picture, believe bad power supply

I to have an LG37LC2D where bottom 2 inch of picture will distorts when first turned ON. After about an hour, the picture gradually gets better. I have ordered power supply replacement capacitors as per members previous posts and will let you know how I make out later.

[cm12]

Re: LG 37LC2D No picture, believe bad power supply

I offered to fix my folk's LG 37LCD2 based on the common symptoms that pointed to capacitor replacements for the power supply, and I figured hey, I have a soldering iron and took Electronics 101 20 years ago, I can help them. I went ahead and bought the capacitors for all but the 2 largest (C500 and C150).

I went ahead and desoldered everything, without thinking to diagram which needs to go where. Ignorant newbie mistake I guess.

Does anyone have a listing or diagram which could help me with which specific capacitors go where?

[rlega]

Re: LG 37LC2D No picture, believe bad power supply

Hello everyone,

I got an LG 37LC2D for $20 because after 30mins of being on, it would turn off, then it would not come back on. I found this post online and I wanted to say thank you all that have provide enough info and cooperated to help others with issues.

So far what I noticed is 1 cap that is bulge (1000uF 16v). I have an in-circuit tester that allows me to test the rest of the caps. I know I won't get the correct reading all the time if caps are parallel, so I will have to remove them and check them with the Supco MFD10 Digital Capacitor Tester I have.

@cm12 - I have added a picture with the caps location, hope it helps.

Thank you all for such a GREAT site

[cm12]

Re: LG 37LC2D No picture, believe bad power supply

rlega - Thanks so much!

Looking forward to my attempt.

[cm12]

Re: LG 37LC2D No picture, believe bad power supply

Finally put the TV back together and it's working like new once again. Thanks all who have contributed to this helpful thread and helped!

[rlega]

Re: LG 37LC2D No picture, believe bad power supply

@cm12 - I'm glad you got it working.

Movie and time

[minikoopa]

Re: LG 37LC2D No picture, believe bad power supply

Hi there,

Just wondering how long caps in this PSU would hold a charge after being disconnected. Scared of killing myself.