Lg 60px950 no picture or sound

[newtothis]

Re: Lg 60px950 no picture or sound

I don't know, why you said ignore my post?

I am saying ignore mine *EDITED*

[tw2005]

Re: Lg 60px950 no picture or sound

I don't know, why you said ignore my post?

Nobody is saying ignore your post.

By what you describe sounds like it must be a faulty mainboard if the test patterns work ok using the jumpers on the logic ctrl board

[ObsessedGeorge]

Re: Lg 60px950 no picture or sound

Nobody is saying ignore your post.

By what you describe sounds like it must be a faulty mainboard if the test patterns work ok using the jumpers on the logic ctrl board

I'm sorry but English is not my native language, so l did not understand newtothis' post properly.

That's what l was thinking too.
I had some co-technicians in my store to see if they can help, and they said that Mainboards fail very rarely in Plasma TVs.
Can the Mainboard be repaired or do l have to order a new one?

[tw2005]

Re: Lg 60px950 no picture or sound

I'm sorry but English is not my native language, so l did not understand newtothis' post properly.

That's what l was thinking too.
I had some co-technicians in my store to see if they can help, and they said that Mainboards fail very rarely in Plasma TVs.

Can the Mainboard be repaired or do l have to order a new one?

I would say find a board, repair would be complex unless it's something simple like a bad cap or voltage reg. Could be corrupted eeprom or the BGA chips have faulty solder joints from thermal stress.

I think any board is suspect to failure, Buffers, ysus, Zsus, power supply main and logic control would be the common ones.

not much left after that list but sounds like you isolated the main and did the auto run test on the logic board and got the test patterns.

Afraid with that info i would say mainboard. I'm sure you'll get some other opinions.

[ObsessedGeorge]

Re: Lg 60px950 no picture or sound

I forgot to mention the Control board's LED behaviour.

It blinks 4 times and in the 4th blink it stays on for 2 seconds. Pauses and repeats.
After a while it does blinks different.
It stays on for 2 seconds, then blinks once. Repeats once and pauses.

I don't know if this helps you.

[ObsessedGeorge]

Re: Lg 60px950 no picture or sound

Any other suggestions?

[Anh116]

Re: Lg 60px950 no picture or sound

I have an LG 60PX950-AA plasma TV that I purchased in Feb 2011. When I turn mine on I will see a faint white picture across the whole screen for about a second then blacks out as if the TV is off. There is no sound. Prior to this my son told me when he was watching TV the screen flicked on and off a few times then stayed off. Volume also cut out.

The following picture is what the back of my TV is:

http://postimg.org/image/ajvcfv0fn/

The repair process for no picture or sound:

http://postimg.org/image/68bc4liwj/

Repair process no picture with sound

http://postimg.org/image/3uoszuf3n/

The following is the voltage label for my TV:

http://postimg.org/image/bdcjm7vub/

Tested voltage for Va is 59.6 and Vs is 202.3 using the following test points to earth:

http://postimg.org/image/76rp6vw8j/

Voltage for Vy is 179.4 and Vsc was 149.5 using the following test points:

http://postimg.org/image/accax3eur/

Voltage for Vzb is 104.6 using the following test point:

http://postimg.org/image/zfos3cn3n/

I tested voltages and the following connector on the power board and they where all 5v:

http://postimg.org/image/wqtzdbhmb/

The ASIC on board LED light will light for about 2 sec then blink once repeating this once more. ( http://postimg.org/image/asxijj2lv/ )

The Y board and Y buffers have been replaced with no success.

Where is the next test point in the repair process is "B+ voltage on the power board/control /Check B+(5V)" etc.

Is there anything else to check?

Cheers

Winston.

Hi,

I have an LG 50PA6500 with a similar problem. I have a standby light but no picture or sound. I want to test the PSU voltages at the plug going to the main board. Could someone tell me what these are meant to be?

[Davidl81]

Re: Lg 60px950 no picture or sound

I have a 60PX950 with a similar issue. My TV will power on, but I get no display at all on the screen. I can tell that I have power to the screen since it has that slight glow that the screen is on, but I get no display at all. I can press the volume or menu buttons and I see the light on the bottom flash, but nothing comes up on the display. It seems like a board that controls the display is out, but how would I test what board to replace?

Before this happen I would get tow vertical pink lines in my screen that would appear from time to time, but go away for no given reason.

[Arcadior]

Re: Lg 60px950 no picture or sound

Hello winniliss,
The links for the pics do not work.
Could you send new links.
Thank you so much.

[nobbnobb1]

Re: Lg 60px950 no picture or sound

Yes. Just realised I made this image for a different user so can use that anyway...

Unplug TV power
Jumper red holes with wire on the control board
Unplug the right hand ribbon cable on the control board
Turn the TV on

Do you get cycling test patterns?

I'm having the no picture problem on my TV. I tried this jumper test and my TV displays the test patterns properly! What does this mean? Bad main control board?

[tvtimmy]

Re: Lg 60px950 no picture or sound

Yes, bad mainboard.

[diif]

Re: Lg 60px950 no picture or sound

I'm having the no picture problem on my TV. I tried this jumper test and my TV displays the test patterns properly! What does this mean? Bad main control board?

Usually a failed/failing BGA under the processor on the mainboard, fixed with a reball or a reflow.

[nobbnobb1]

Re: Lg 60px950 no picture or sound

Usually a failed/failing BGA under the processor on the mainboard, fixed with a reball or a reflow.

Thanks. Is there a reason why people put the entire board into the oven and heat to 385F for 10 mins instead of just applying heat local to the processor via a heatgun? Seems overkill to zap the whole board and risks damage to other components. I've only performed a BGA repair once on an Onkyo where I heated up the failed chip to 200C via a heatgun and also added flux to help clean off any oxidation.

[diif]

Re: Lg 60px950 no picture or sound

Yes, they think it's a cake, they don't have anything else or don't know any better or think it's the right way as they've seen a YouTube video or two.

The thermal stresses of expansion and contraction over time crack some of the joints between the processor and board. This join needs to be remade. Ideally with brand new balls with lead to aid in the expansion and contraction. Ideally it needs to be done with the minimum amount of stress to the rest of the board.

Using an oven heats everything to around 220c, not an ideal situation with plastic parts and electrolytic caps. A heat gun used for stripping paint can easily reach over 220c so care must be taken. There is also the risk or damage due to the rest of the board being cold with part over 220c..

I would suggest some sort of compromise perhaps warming the board to around 100c, before quickly removing it and reflowing the processor with the heat gun and flux.

[nobbnobb1]

Re: Lg 60px950 no picture or sound

...

Thank you very much for the advice, I just fixed my TV!

I decided not to bake the entire board, but rather, I took out the heatsink and applied local heating (approx 200C) to the main processor that's under the heatsink. I also made sure to use flux around the chip to help clean things up. On the mainboard, this is the only chip that appears to use BGA soldering so that's why I targeted it. I also added a small 50mm fan over the heatsink (had to make a cutout in the rear metal panel) and powered it off the 5V from the power supply. Hoping this will keep things nice and cool.

[diif]

Re: Lg 60px950 no picture or sound

You're welcome, glad it worked.