LG 47LV5500 Troubleshooting

[DivingRhino]

I was just given a non-functional LG 47LV5500.

The power button light will respond to being turned on (from the remote or touch), and light up white, but nothing else happens, it does not appear as the backlight even comes on.

I have tried a meter on a fuse on the TCON (I know very little, but have read some posts here) and I get zero. Image attached of what I tested and how the meter was set... again, I am a noob with this kind of stuff, but can follow instructions

Does this mean I'm not getting power beyond the initial board, and should get a TCON (that what this board is called?) or am I doing something wrong.

Thanks!
Ryan

[CapLeaker]

Re: LG 47LV5500 Troubleshooting

No, you don't measure voltage on the fuse like that. I see you need a crash course in how electronics work.
But before we get to that, I do have to ask for some high resolution, straight shot pictures of your power supply, main board and tcon. Maybe an extra pic of the PSU area where the ribbon cable goes to the main board. So we can see the pin out names.

[DivingRhino]

Re: LG 47LV5500 Troubleshooting

Well, thanks for helping a noob out!

Here are some pics...

[DivingRhino]

Re: LG 47LV5500 Troubleshooting

Disregard this pic... got it in the prior post.

[Andrew F. Ali]

Re: LG 47LV5500 Troubleshooting

You have a Main Bd problem. Since the Power light comes on but no other response, you should be getting 5V-Stby but no PS-ON signal to the Pwr Bd.

[CapLeaker]

Re: LG 47LV5500 Troubleshooting

could we have another picture of the top right of the power supply, showing the 2 connectors and the pin outs? I can't read it.

[DivingRhino]

Re: LG 47LV5500 Troubleshooting

Here's another shot...

[CapLeaker]

Re: LG 47LV5500 Troubleshooting

On connector P201: check the DC voltages on the PWR on pin and the DRV on pin, while the tv is on.

[DivingRhino]

Re: LG 47LV5500 Troubleshooting

.

[DivingRhino]

Re: LG 47LV5500 Troubleshooting

Pwr gets me 3.44v
and DRV gets me 11.91

[budm]

Re: LG 47LV5500 Troubleshooting

"and DRV gets me 11.91" Are you sure you are on the right pin? The DRVON has to be measured from the bottom side of the board or at the back side of the female connector. The exposed pins you see on the top side of the board are for the LEFT column pins (odd number) of the pinout chart.
BTW, what DCV do you have on the ERROR pin?

LG Power supply-LED driver board EAY62169801
http://www.shopjimmy.com/catalogsear...?q=EAY62169801
Pictures provided by SJ.

[DivingRhino]

Re: LG 47LV5500 Troubleshooting

Ok, doing it from the back (hey look at that, they're labeled there... )

PRV ON - 24.46
DRV ON - 0.033
Error - .000

[CapLeaker]

Re: LG 47LV5500 Troubleshooting

That measurement isn't right either. Those pins have usually something in between 2v and 5v. There are some weird TV that do things a bis different, but none have 12v or 24v on the PSON/BLOn pins.
How about you turn on the tv and measure each pin and use the pin out name.

[budm]

Re: LG 47LV5500 Troubleshooting

Ok, doing it from the back (hey look at that, they're labeled there... )

PRV ON - 24.46
DRV ON - 0.033
Error - .000

What did you use for ref. GND for the meter? Those readings are wrong.

[DivingRhino]

Re: LG 47LV5500 Troubleshooting

Sorry, haven't been back to this for a couple of days.

I used the chassis of the TV for ground.

Image of where and how I was testing as well as a reading for each pin (left and right) provided in the attached chart image as well.

Note, as far as the TV being "ON", I click the on button on the remote and the lower right light goes steady white. I presume that's on, but given no sound or picture, I don't know.

[budm]

Re: LG 47LV5500 Troubleshooting

PRV ON - 24.46
DRV ON - 0.033
Error - .000

https://www.badcaps.net/forum/attach...1&d=1476247393

So the PWR ON is NOT 24.46V after all, it is 3.37VDC.
DRV ON = BL-ON which you are not getting from the main board to turn on the backlights circuits.

[pott0120]

Re: LG 47LV5500 Troubleshooting

PRV ON - 24.46
DRV ON - 0.033
Error - .000

https://www.badcaps.net/forum/attach...1&d=1476247393

So the PWR ON is NOT 24.46V after all, it is 3.37VDC.
DRV ON = BL-ON which you are not getting from the main board to turn on the backlights circuits.

I am having the same exact problem with my TV, I even got 3V when I measured the power on which should be 24V. How do I correct this? My friend recommended replacing capacitors. Thoughts?

[budm]

Re: LG 47LV5500 Troubleshooting

The PWR_ON is the control signal and will never be 24V there, please report what Voltages you are getting on ALL the pin as shown in post #15 chart.

[nomoresonys]

Re: LG 47LV5500 Troubleshooting

There's a legend/map near top of board for connector P201, there are TWO rows of pins for testing, in this case 24 pins. Here's a video of powerboard testing, HEED ALL HIGH VOLTAGE CAN BE DEADLY WARNINGS. https://www.youtube.com/watch?v=4v8DcqCNG4A