Lg 60px950 no picture or sound

[winniliss]

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.

[tom66]

Re: Lg 60px950 no picture or sound

Can you post a clear picture of the ASIC board (I call it the Control board)? There is one simple test that will check if 3DF/Main Board are faulty.

[winniliss]

Re: Lg 60px950 no picture or sound

Can you post a clear picture of the ASIC board (I call it the Control board)? There is one simple test that will check if 3DF/Main Board are faulty.

Will this help otherwise I will have to wait until the weekend.

http://postimg.org/image/yazbbpq0j/

[tom66]

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?

[winniliss]

Re: Lg 60px950 no picture or sound

I can do that tomorrow night. In the repair process after checking Vy, Vsc and Vzb, where on the power board is check B+ voltage on the power board?

[tom66]

Re: Lg 60px950 no picture or sound

I am not entirely sure what LG mean by B+ voltage, as that is an old term relating to CRT TVs. I would take a guess they mean the voltage across the large 450V capacitors at the top of the PSU. When in standby you will get approx 160V and when running you should get around 380 to 420V.

[winniliss]

Re: Lg 60px950 no picture or sound

Sorry for the delay,
Between unpacking and shift work, today is the first time I have been able to look at the TV.
I placed the jumper in as instructed. No test patterns. Still the same result of when I turn the TV on the screen flicker on then off and nothing.

[tom66]

Re: Lg 60px950 no picture or sound

OK, do you have a digital multimeter available? Next step is to check some voltages. At the top right or middle of the plasma panel (the internal metal of the TV) there should be a sticker marked something like "LG Electronics PDP60K9##### Made in Mexico" or such. Can you get a picture of this sticker?

[winniliss]

Re: Lg 60px950 no picture or sound

I have a multimeter. My first post has all the pics you need and what voltages I got. There is that b+ voltage to check in the repair process chart but not sure where it is.

[tom66]

Re: Lg 60px950 no picture or sound

Sorry, missed that.
60R1. You beat me to it, testing -Vy and Vsc, getting mixed up with another guy.
So are these voltages steady or do they drop out?

[winniliss]

Re: Lg 60px950 no picture or sound

Voltages are steady. After checking y and z sus it goes on to check b+ voltage on the control board. If not good check power board.

[Alastair E]

Re: Lg 60px950 no picture or sound

I am not entirely sure what LG mean by B+ voltage, as that is an old term relating to CRT TVs. I would take a guess they mean the voltage across the large 450V capacitors at the top of the PSU. When in standby you will get approx 160V and when running you should get around 380 to 420V.

On a side-note-- +B was a generic term not only used for CRT TV sets. It was used for practically everything electronic.

+A was the term--not often used--but related to the Heater-Supply of Valves/Tubes. Firstly 2V then 4V and as technology progressed with Indirectly Heated valves the more normal 6.3V

Originally from the 'A-Battery' of early wireless sets of 20's and 30's often a lead-acid accumulator was used, hence +A.

+B was the term used for the Main supply voltage--normally the highest--from which other supplies were often derived, via regulators, resistor-droppers etc.

Origin from the 'B-Battery' of wireless sets, often called, the HT Battery, of up to 120V supplied by a non rechargeable dry-battery, so +B was then carried on as the main supply term.

+C. +D etc were lower supplies than +B and these terms not often used. I believe Philips used these designations the most as I recall....

[winniliss]

Re: Lg 60px950 no picture or sound

So in relation to the following flow chart ( http://postimg.org/image/68bc4liwj/ ) after checking Y Sus and Z sus what do I check on the control board in relation to voltages? and then the last step being:
Check control board
- Led on (LED light will light for about 2 sec then blink once repeating this once more. What does this mean ?)
- 1.8v, 3v, 5v FET
- ROM update.

Cheers

Winston.

[winniliss]

Re: Lg 60px950 no picture or sound

Hello,
Anyone got advice for my previous post. I would like to get this tv going (minimal cost) or sell the boards I brought and scrap the rest.

Cheers

Winston.

[Truncatedhose]

Re: Lg 60px950 no picture or sound

I can say that I recently followed this thread and performed the above test and indeed found that the main board was the culprit, but I have a problem: While the new main board repaired the set and it now comes on, it has no remote reception. I don't know whether I have a defective main board or if there is some other problem. Can anyone please help me troubleshoot this? I think I will start a new thread.

[ObsessedGeorge]

Re: Lg 60px950 no picture or sound

Hello, I have the same Plasma LG TV - 60PX950N, and the problem is:
Once you turn it on, the panel lights up for about 1 second then it goes off. The TV is still on but l have no sound.

- Voltages are OK (5V, Va:60V, Vs:203V, -Vy:-180V, Vsc:150V and Vzb:105V)
- The cycling test patterns work fine
- I get no picture to another TV by connecting them together with a scart cable
- Pressing the TV's front touch buttons light up the led indicating that they work

Any ideas to where the problem is?

[newtothis]

Re: Lg 60px950 no picture or sound

Hello, I have the same Plasma LG TV - 60PX950N, and the problem is:
Once you turn it on, the panel lights up for about 1 second then it goes off. The TV is still on but l have no sound.

- Voltages are OK (5V, Va:60V, Vs:203V, -Vy:-180V, Vsc:150V and Vzb:105V)
- The cycling test patterns work fine
- I get no picture to another TV by connecting them together with a scart cable
- Pressing the TV's front touch buttons light up the led indicating that they work

Any ideas to where the problem is?

Ignore this... Not thinking right today.

[ObsessedGeorge]

Re: Lg 60px950 no picture or sound

Ignore this... Not thinking right today.

Is there something wrong with my post?

[newtothis]

Re: Lg 60px950 no picture or sound

Is there something wrong with my post?

No was something wrong with mine LOL

[ObsessedGeorge]

Re: Lg 60px950 no picture or sound

No was something wrong with mine LOL

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