Another dump find, so someone must have given up on it already.
The list price was $700, so I figure it's worth giving it a try.
When I plug it in, the display briefly says Hello, then the volume level, the scrolls Please Wait. There are 4 LEDs under the display words that go in a three second loop of 2 inner on, all 4 on, all 4 off.
From the remote, the volume level changes on the display, but that seems to be the only activity.
The owners manual says to hold the microphone mute button for 5 seconds to reset, but nothing there.
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pauldow
Senior Member
Last Activity: 10-22-2023, 07:58 AM
Joined: 10-07-2012
Location: CT
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LG SN9YG Soundbar - Stuck with Please Wait
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Re: LG 55LM6400-UA Standby LED Blinks off. No sound or Picture
This was a dump find, so I don't know its history.
It didn't smell of smoke. Tar should have good electrical insulating resistance. :-) It's like in the days when smoking was allowed on airplanes. The tar would seal the seams in the pressurized fuselage joints. It was a maintenance headache, but it was easier on the pressurization systems.
And cats too. I've opened up computers that have sat on the floor for years, and I was able to peel the dust and fur off the heat sinks. Those were easy to diagnose why... -
Re: LG 55LM6400-UA Standby LED Blinks off. No sound or Picture
I tried heating it again up to 225 deg C, and there's still no change. I do use a separate toaster oven from the dump for this kind of thing.
I have had some success with other devices with reheating, but as you say, it looks like someone already tried and failed with this one.
From the top, I don't see any cracks in the IC, but there could be something bad underneath, or internally.
Looks like another learning experience.Leave a comment:
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Re: LG 55LM6400-UA Standby LED Blinks off. No sound or Picture
OK. You guys have convinced me to give it a couple more tries. I'll work on it again Friday.
Thanks,
PaulLeave a comment:
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Re: LG 55LM6400-UA Standby LED Blinks off. No sound or Picture
Thanks for diagnostic suggestions.
I removed the cables between the power supply and main board, and I just get the 3.5 volts on the appropriate pins. All others are 0.
I removed the heat sink, wrapped the board in aluminum foil, and cut out a hole where that IC is. I put in in a toaster oven for 10 minutes, and then gave it a brief shot from my heat gun. I was able to see 200 deg. C. There is no change in the symptoms though.
This was a dump find, so it is entirely possible that the main board...Leave a comment:
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Re: LG 55LM6400-UA Standby LED Blinks off. No sound or Picture
Thanks for the reply Vince,
I tried my heat gun, but no change in symptoms. I may not have gotten it fully up to 200 deg C though. It's tough getting a temperature reading off the reflective label. It seems to never go up that last 25 deg. I'll give it one more try.Leave a comment:
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LG 55LM6400-UA Standby LED Blinks off. No sound or Picture
On this TV, the standby LED is lit. When I press the power button, the LED goes out for 1 second, and it comes back on.
I tested the LED strips, and they're all OK. I checked the larger capacitors on the power supply along with the fuses.
I disconnected the cable between the power supply and main board, and no LEDs illuminate.
Here's the voltage readings I got. The second column is the reading I get when pressing the power button. Any voltage in that column changes back to the first column value after about a second.
I don't think it's worth spending a lot...Last edited by pauldow; 11-16-2021, 12:37 PM. -
Re: LG 55LB5900-UV Smeary Image
Oh no! I thought IC403 was the EEPROM. I got rid of the set already, so I don't have the ability to get a detailed photo to check the part numbers again. I thought IC403 was a memory circuit.
On the photo I took, I thought it looked like IC403 showed 4625. That would be the audio amplifier. (Which would be a strange place to put it on the board.) Now taking a closer look, I now see that is it 4[B]G[/B]25, which is the EEPROM.
I did try to power it on, and I only got the backlights. No image on the screen.
I also...Leave a comment:
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Re: LG 55LB5900-UV Smeary Image
I got a tiny resistor back in place, but I wasn't able to put a capacitor back. It just wouldn't stay in place, and it doesn't look good after all the time it spent with the tip of my soldering iron.
I think I'm going to have to give up on this one.
Thank you Diah and Davi.P for all your help on this. I have two other LG televisions in my repair queue, so I think the lessons you passed on to me won't go to waste.
Thank you for all your help on this.
PaulLeave a comment:
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Re: LG 55LB5900-UV Smeary Image
OK. I misunderstood what you were recommending I do with the EEPROM.
I put the original EEPROM on my replacement board, and the TV wouldn't turn on. I took a closer look, and while the soldering looks good around the integrated circuit, unfortunately I pulled off a couple of very small SMD components nearby. I did find them, but I don't know if I'll be able to get them back in place since they are so small.
I'll be back to let you know what happens.
Thanks
PaulLeave a comment:
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Re: LG 55LB5900-UV Smeary Image
I changed the items in Tool Option 1 as I said in my message of March 14, but I put them back the way I started. I also changed the serial number, but I don't think that affects anything.
The right side of the screen is straight. I think it was just the angle I was holding my camera.
I'm having trouble finding old firmware. The LG support site only has the current version, and other pages that I've found for firmware downgrades so far are for WebOS and network connected televisions. This one has no data connectivity.
I'll...Leave a comment:
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Re: LG 55LB5900-UV Smeary Image
Thanks for the reply.
When I removed each side of the T-Con to panel cable, the panel showed on side disconnected as solid grey. The side that was still connected still had the bad image.Leave a comment:
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Re: LG 55LB5900-UV Smeary Image
Thank you again for the help.
Here are the photos you asked for. The board on the white background is the original.
I've read some of these boards may have the old Ball Grid Array solder problem. Do you think it would be worthwhile to do the ol' toaster oven procedure on it?...Leave a comment:
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Re: LG 55LB5900-UV Smeary Image
First let me give you a very belated Thank You for pointing me in the right direction.
Too many projects put this TV on the back burner. (Actually way back.)
I also had difficulty getting the software together on my old Galaxy S4 phone. Looking through other instructions, I saw that I could use a Logitech Harmony remote. I had one that was already set for a LG television, so I'm able to get into the EZ-Adjust, In-Start and In-Stop menus and change things.
I have the panel set to 55", set the serial number (if that makes...Leave a comment:
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LG 55LB5900-UV Smeary Image
Hello,
I've got the subject TV. When I got it, it only had the Power indicator light, but no activity when pushing the joystick style button.
I replaced the main board, and it powers up, and looks to properly function, but the image isn't clear. It kinda looks like an old IBM CGA quality screen.
Before putting more time and money into this, does anyone know if the initial indication for this problem points to a bad T-Con board, or something within the electronics of the panel? (or something else)
Thanks,
Paul... -
Re: Sharp LC-40LE550U no Backlights due to bad connector
I came across one of these too. Had the image on the screen if the flashlight was shining on it. I opened up the panel as you suggested, and two of those connectors linking the LED strips fell off in my hand.
Resoldered them, got it back together, and it lights up!
See, I do search here before posting a question. :-)
Thanks again.
PaulLeave a comment:
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Re: Samsung UN46FH6030F Vertical Lines Across Screen During Movement
The T-Con board was the problem.
The recycler will need to wait until they get this one
Thank you very much for all your advice.Leave a comment:
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Re: Samsung UN46FH6030F Vertical Lines Across Screen During Movement
Thank you for the replies.
It looks like SJ is out of stock, so I ordered one through eBay.
I tried a couple searches here, but didn't see anything that was very similar to the symptom I have. Nice find budm.
I'll reply in a few days when it comes in.
Thanks again,
PaulLeave a comment:
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Re: Samsung UN46FH6030F Vertical Lines Across Screen During Movement
Thanks for the suggestion, but there was no change after I removed the ribbon cables, wiped them with an alcohol swab, and reconnected.
I also pulled the heat sink off the T-CON, to see if pressing on the BGA mounted chip under there would cause any change, but it didn't.Leave a comment:
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Samsung UN46FH6030F Vertical Lines Across Screen During Movement
My neighbor asked me to look at this problem. I thought it might be a BGA problem, but I get no change when pressing on the circuits with that attachment on the main board, and on the T-Con.
The problem doesn't seem to appear on images without movement, such as a DVD or setup menu. The lines appear on both antenna and HDMI inputs.
Does anyone have a suggestion on what I can look at next?
Thanks...
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