Newbie with LG 37LH5000 (PS?) problem.

[MickyLuv]

Re: Newbie with LG 37LH5000 (PS?) problem.

Back of TV and individual boards.

[MickyLuv]

Re: Newbie with LG 37LH5000 (PS?) problem.

Unfortunately this is not an exact science. Trial and error. Have you also taken cover off t-con and heated and tested voltages on it? Could also be a panel issue. Try flexing panel a little see if it has effect.

Thanks for the tips dskall,
I've tested the voltages on the power supply board now and they seem to be OK.

So according to the flowchart and what you already suggested, I'm looking to testing the t-con board now.

I'll remove the cover and heat the board as you say, then I'll go and look for info on the correct voltages.

Is it worth cleaning the ends of the t-con ribbon cables?
I have seen this mentioned elsewhere but I don't know if it applies in this situation.

Regards,

MickyLuv

[vinceroger69]

Re: Newbie with LG 37LH5000 (PS?) problem.

did you check the voltages when there is no picture and also when the picture is working fine certaily worth cleaning the ribbon cable cable ends but also remember there are some more ribbon cables on the top of the tcon board that goes too the lcd panel pcb on that pcb are the lcd panel tab bonds that are bonded to the panel pcb and lcd panel any one of these connectons can give you this issue you have i guess.On the mainboard you can see a heat sink if you heat that area up does that make the picture alter?

[MickyLuv]

Re: Newbie with LG 37LH5000 (PS?) problem.

did you check the voltages when there is no picture and also when the picture is working fine certaily worth cleaning the ribbon cable cable ends but also remember there are some more ribbon cables on the top of the tcon board that goes too the lcd panel pcb on that pcb are the lcd panel tab bonds that are bonded to the panel pcb and lcd panel any one of these connectons can give you this issue you have i guess.On the mainboard you can see a heat sink if you heat that area up does that make the picture alter?

Thanks, I'll try those things next.

[MickyLuv]

Re: Newbie with LG 37LH5000 (PS?) problem.

did you check the voltages when there is no picture and also when the picture is working fine certaily worth cleaning the ribbon cable cable ends but also remember there are some more ribbon cables on the top of the tcon board that goes too the lcd panel pcb on that pcb are the lcd panel tab bonds that are bonded to the panel pcb and lcd panel any one of these connectons can give you this issue you have i guess.On the mainboard you can see a heat sink if you heat that area up does that make the picture alter?

I took the cover off the t-con board, switched the TV on and wiggled the cables around the board. The picture came on immediately, then froze, then a new effect which was the screen divided in half vertically with some coloured vertical bars on one side and and a blank screen on the other.

[dick_barton]

Re: Newbie with LG 37LH5000 (PS?) problem.

Hope you haven't blown your tcon board. Reseat the ribbons carefully with the power off. You may also need to check you still have voltage at the fuse on the board.

[MickyLuv]

Re: Newbie with LG 37LH5000 (PS?) problem.

Hope you haven't blown your tcon board.

Me too! Do the symptoms indicate that I might've?

Reseat the ribbons carefully with the power off. You may also need to check you still have voltage at the fuse on the board.

On closer inspection the t-con board end of one of the cables from the mainboard, keeps slipping out. It looks like part of the plastic locking button at the side is missing. This cable has a metal mating part to connect to the metal socket on the board.

[vinceroger69]

Re: Newbie with LG 37LH5000 (PS?) problem.

Me too! Do the symptoms indicate that I might've?


On closer inspection the t-con board end of one of the cables from the mainboard, keeps slipping out. It looks like part of the plastic locking button at the side is missing. This cable has a metal mating part to connect to the metal socket on the board.

can you upload a picture of the area you think is broke/missing i wonder if this was causing your initial problem

[MickyLuv]

Re: Newbie with LG 37LH5000 (PS?) problem.

can you upload a picture of the area you think is broke/missing i wonder if this was causing your initial problem

I'll send pictures this morning.

The connector is broken because I found the bit of plastic that came off it.

I'm pretty sure I broke it myself, trying to work out how to release the ribbon cables, so that I could clean the ends.

Every set of connectors is a different design. I still have one more set from the t-con board to the panel to figure out the release of.

At least I've now found the problem area.

[MickyLuv]

Re: Newbie with LG 37LH5000 (PS?) problem.

Hope you haven't blown your tcon board. Reseat the ribbons carefully with the power off. You may also need to check you still have voltage at the fuse on the board.

Thanks, I'll do what I can of that.
Looks like I'll have to buy a set of cables from EBay unless it's possible to buy just the replacement metal connector by itself.

[MickyLuv]

Re: Newbie with LG 37LH5000 (PS?) problem.

Just cleaned the ribbon cables.
After 1 hour fairly good picture. Some feint horizontal lines near top of panel.
But at this point, picture freezes. Giving the panel a wiggle, picture animates, then freezes again. This is since I took the cover off the t-con board and disturbed the cable ends to clean them.

I can see where the ribbon cables go from the t-con board to the panel but visual or other access to the LCD panel tab bonds is not available at this level of strip down. Maybe I need to go further in.

the heatsinks are just warm on the power supply board. After waiting 90 minutes to see how the picture develops, I'll heat those heatsinks with the hair dryer.

Also, after the 90 minute wait I'll check the voltages on the power supply while the picture is at it's "best".

Thanks for all the good advice.

[MickyLuv]

Re: Newbie with LG 37LH5000 (PS?) problem.

After 3 hours, great picture, no lines, no freezing.
Display now seems faultless.
Seems identical to the same problem I started with.

As the repair flowchart pinpointed the t-con board as the problem can anyone please point me to t-con board component testing procedures?
Further advice of any type would be most welcome.

[dskall]

Re: Newbie with LG 37LH5000 (PS?) problem.

If you can flex panel and effect it then it is probably panel fault.

[MickyLuv]

Re: Newbie with LG 37LH5000 (PS?) problem.

Tested the voltages from the power supply after the TV has been running for 4 hours. The heatsinks on the power supply board are now hot.
All the voltages are as they should be and were when the the test was done at initial switch on.

Those pins and wires that have labels describing other than a specific voltage,or ground,
such as:

NC
BRI
NC

on the left side

&

PWM-DIM
Error
INV
ON/OFF
P0WER ON

on the right


These have readings but I don't know what they should be.

[vinceroger69]

Re: Newbie with LG 37LH5000 (PS?) problem.

as above if you flexed the lcd panel/surround and the picture camo on ok it does sound like a lcd pnel/tab bond issue i hate faults like this as very hard to pin point the exact fault location/part, on the back metal tc chassis theres usually a white sticker saying what lcd panel is used in this set.

[MickyLuv]

Re: Newbie with LG 37LH5000 (PS?) problem.

If you can flex panel and effect it then it is probably panel fault.

I've flexed the panel as much as I'm able, which is some, considering the rigidity of the metal chassis. It had no effect on the panel display, which is currently very good to excellent, because the tv has been on for a few hours.

[MickyLuv]

Re: Newbie with LG 37LH5000 (PS?) problem.

as above if you flexed the lcd panel/surround and the picture camo on ok it does sound like a lcd pnel/tab bond issue i hate faults like this as very hard to pin point the exact fault location/part, on the back metal tc chassis theres usually a white sticker saying what lcd panel is used in this set.

Thanks Vince,
I didn't flex the panel to get the picture to come on, I wiggled the t-con cables.

After several hours the picture is "perfect" and flexing the panel as much as I'm able doesn't adversely affect the quality of the picture.

I'm considering putting the back on the TV and just leaving it switched on all the time. Better still, leaving it in standby alone might do the trick but I somehow doubt that that will maintain enough heat in the boards.

Photo of label attached.

[dskall]

Re: Newbie with LG 37LH5000 (PS?) problem.

You might want to look through these. The gamma checker can help you with t-con voltages

[MickyLuv]

Re: Newbie with LG 37LH5000 (PS?) problem.

You might want to look through these. The gamma checker can help you with t-con voltages

Thanks dskall,

I'll read these while I'm on holiday in Newquay next week.
I was worried that I was going to be stuck with a novel for a while there.

[stefan94stefan]

Re: Newbie with LG 37LH5000 (PS?) problem.

Thanks dskall,

I'll read these while I'm on holiday in Newquay next week.
I was worried that I was going to be stuck with a novel for a while there.

Hi, try to heat with a hairdryer top right corner or top left corner from screen there is a problem with panel it will turn on in seconds.