LG UF6450 half screen is black, half is blue/white

[budwich]

Re: LG UF6450 half screen is black, half is blue/white

The powering for the tcon is being "switched" thru the main board. As suggested, check to see if you are getting anything on the small cable going to the tcon. Go from the result.

[budm]

Re: LG UF6450 half screen is black, half is blue/white

See some of the Voltage test points.

[jskuyper]

Re: LG UF6450 half screen is black, half is blue/white

I have the same voltage on both sides of the fuse f1

[jskuyper]

Re: LG UF6450 half screen is black, half is blue/white

Tested each point in the image and have voltage on them

[dick_barton]

Re: LG UF6450 half screen is black, half is blue/white

Tested each point in the image and have voltage on them

But what were the readings at those points?

[jskuyper]

Re: LG UF6450 half screen is black, half is blue/white

All volts readings
Vcc 3.3
Hvdd 8.07
Vcc18 1.8
Vcor 1.215
Va2 8.2
Vin 13.1

[budm]

Re: LG UF6450 half screen is black, half is blue/white

How about VDD on the top left of the picture that I marked.
One of the important Voltage is the AVDD (~ 20V) which I cannot see the test point on the T-CON board, it may be around diode D3 located close to inductor L3 and U2, please check the Voltage there at D3 Cathode.
http://tvrepairsolution.blogspot.com...lcd-panel.html

[jskuyper]

Re: LG UF6450 half screen is black, half is blue/white

How about VDD on the top left of the picture that I marked.
One of the important Voltage is the AVDD (~ 20V) which I cannot see the test point on the T-CON board, it may be around diode D3 located close to inductor L3 and U2, please check the Voltage there at D3 Cathode.
http://tvrepairsolution.blogspot.com...lcd-panel.html

Vdd is 16.6
Could not find avdd including a close photo of the area you are speaking of

[budwich]

Re: LG UF6450 half screen is black, half is blue/white

The powering for the tcon is being "switched" thru the main board. As suggested, check to see if you are getting anything on the small cable going to the tcon. Go from the result.

I don't see where you did any checks around this connector? Check the labelling around the connector at either the tcon or main board and measure the pins (to ground).

[budwich]

Re: LG UF6450 half screen is black, half is blue/white

Here you go

it that picture (post 3) with all cabling attached / intact?

[jskuyper]

Re: LG UF6450 half screen is black, half is blue/white

it that picture (post 3) with all cabling attached / intact?

Yes

[budwich]

Re: LG UF6450 half screen is black, half is blue/white

thanks... not looking right with all cables attached. It would appear that the one on the left (looking at the set) is not connected.

further, i asked about getting you to measure the voltages at the small connector / cable coming from the main board to the tcon... no response to this. :-(

[jskuyper]

Re: LG UF6450 half screen is black, half is blue/white

thanks... not looking right with all cables attached. It would appear that the one on the left (looking at the set) is not connected.

further, i asked about getting you to measure the voltages at the small connector / cable coming from the main board to the tcon... no response to this. :-(

I added an image and checked voltage on each point and one was 3.5v rest were 1.7V is there another area I should be checking?

[budwich]

Re: LG UF6450 half screen is black, half is blue/white

ok... thanks... hmmm. I was expecting higher voltages there... maybe. Other types of sets usually have some form of 12v coming thru seperate connectors from the signal / large flat ribbons. Is there any labelling associated with those pins at the other end (ie. main board)?

[jskuyper]

Re: LG UF6450 half screen is black, half is blue/white

What are next steps. Tcon or main board?

[nomoresonys]

Re: LG UF6450 half screen is black, half is blue/white

There's a tcon if you want to throw one at it: https://www.tvpartstoday.com/6871L-3...871l-3851f.htm

[jskuyper]

Re: LG UF6450 half screen is black, half is blue/white

Put a new tcon and still has the same behavior. Any other suggestions?

[nomoresonys]

Re: LG UF6450 half screen is black, half is blue/white

Looks like the XDA engine BGA chips are failing pretty regularly, don't know that I would even trust a used mainboard, maybe a repair service with at least a 6 month guarantee, a good question to ask would be how they plan on repairing it but they might not want to tell their methods, seems there is some revised boards but didn't see any, in searching, looks like even the boards that cost as much as 200 dollars+ are sold out.

[nomoresonys]

Re: LG UF6450 half screen is black, half is blue/white

One site claims these parts will substitute but I would triple check that: Mfg Part Number: EBT64048903 Board Number(s): EAX66703203(10) Substitute Parts: CRB35036401, CRB35036501, EBT64048902, EBU63478202 Compatible Models: LG 55UF6450 UA BUSYLJR

[jskuyper]

Re: LG UF6450 half screen is black, half is blue/white

If the tcon board replacement had no effect. Is the next thing to go to is the main board or am I just throwing money away? I see the tcon ribbons attach to another board assuming that is the lcd. Could it just be a bad lcd?