lg 60pb660v plasma tv

[thuss]

]Hi

Has anyone worked on a 60pb660v?

It turns on and displays a grey/grainy screen with some purple hazing and lasts for about two seconds the screen is grey white with some purple haze.

But then I disconnected the x sus (which also provides the power to the y sus) from the psu, the power supply hits its voltages repeatedly but go back down- I think its the main board? Any suggestions thanks.

The voltages keep reaching vs and va (205/55)and then reduce as the power supply clicks. Thanks in advance

[chrismurphy]

Re: lg 60pb660v plasma tv

The fault you describe points to Z SUS being faulty faulty

[maxvalutech]

Re: lg 60pb660v plasma tv

You should try for power board voltages all coming and staying up without main board connected. Short rl-on to gnd on main board side of connector using small resistor preferably. This check is covered pretty well in many posts herein. Keep x connected for first check.

[thuss]

Re: lg 60pb660v plasma tv

Thank you for the response.

But if it was a faulty z sus-then upon disconnecting the z sus I would have expected the power supply to stay on (with main board connected)?

I thought its the main board just continually rebooting?

(With a faulty z sus as well.)

But I will try and using a small resistor. Thanks

(I have attached a few photos of the display but its hard to catch a proper picture)

[maxvalutech]

Re: lg 60pb660v plasma tv

On later models from around 2012 on disconnecting y or x prompts power shut down. You would need to research this before reaching a conclusion - I was caught out on a Samsung recently and spent money for no gain.

[Hamie]

Re: lg 60pb660v plasma tv

I've had loads of problems on this model with a faulty y-sustain and buffers.
With the buffers unplugged does the tv stay on and give -vy voltage.

[thuss]

Re: lg 60pb660v plasma tv

Thanks I will unplug the buffers from the tv and keep you updated. But when you mean unplugged do you mean removed from screen ribbons and Y sus?

[maxvalutech]

Re: lg 60pb660v plasma tv

The idea here is elimination so if main board is only one disconnected from power board and the voltages all coke and stay up when powerboard is jumpered to start then main is culprit but as y-sus is more likely source of problem if you separate the sus from the buffers with all other connection in place then if voltage vs stays up the buffer bad otherwise vice versa and sus very sus!

[Hamie]

Re: lg 60pb660v plasma tv

No unplug the buffers from the y-sustain.

Don't run the buffers when they are not connected to the orange panel ribbons as you can damage them.

[thuss]

Re: lg 60pb660v plasma tv

I got carried away and removed the buffers totally.

The vy voltage on the y sus does the same i.e hits 186v and then goes down when the power supply clicks, which is every several seconds.

Its the same as when only the psu and main board were connected.

should I now disconnect the main board from the psu and put a jumper wire/resister (resistor value?) main board plugside from the RL onto ground?

Can I use a paper clip as a jumper?

[maxvalutech]

Re: lg 60pb660v plasma tv

As the main board is continually trying to do its job and turn the power board on it would seem the fault is either with the power board itself (protection circuit finding fault) or more likely the y-sus as first choice given result with buffers off - x boards least likely usually. I'm a novice but you can check y and x for shorts with dmm measuring I understand from main voltage input point to ground using ohm setting and recording results here for the experienced guys to interpret.

[thuss]

Re: lg 60pb660v plasma tv

I thought I 'dmention this in the past my led tv did the same i.e voltages continuously repeating themselves and that was cured by a main board replacement. But in this case I will bypass the mainboard and inspect the psu.

[Hamie]

Re: lg 60pb660v plasma tv

To jump the smps on its RL-On to 3.5v (or similar)

Grounding RL-on won't work.

[thuss]

Re: lg 60pb660v plasma tv

Thanks Hamie you are right .After disconnecting the plug from the main board I put a jumper from the 5.2v to the RL-on and the psu stayed on.
All the following voltages were stable I suppose I can turn the vs down a little bit

the vy on the ysus is 187v
the vzb on x sus (I cant remember ) I think 125v
the vs was 236 ( 205v)
the va was 55v

so would it fair to conclude that it is the main board?the Tcon green led is flashing every 2/3 seconds.

[thuss]

Re: lg 60pb660v plasma tv

Forgot to ask could it be a eeprom failure on the main board?

[Hamie]

Re: lg 60pb660v plasma tv

You need to run test patterns on the control board.

[thuss]

Re: lg 60pb660v plasma tv

Can anyone please give me a link to running the test patterns?

When I dont need the info I cant help finding it - now I cant find the page.

If memory serves me right on the tcon board I have to link autogen...........

thats all I can remember

[thuss]

Re: lg 60pb660v plasma tv

Then locate 2 holes marked ext auto gen on the control board an put a wire jumper across them.


Ive never done this before shall I leave the jumper on between the the Rl on 5.2v secondly ext and autogen.

Is there any other jumpers I need to install?

[thuss]

Re: lg 60pb660v plasma tv

I am totally confused, I did the following

1. connected main board back to psu and installed a link between ext and auto gen and diconnected the lvds ribbon - result tv stays on for about two seconds displays a grey white screen with a purple hint and turns of.

2. I disconnected psu to main board and placed a jumper between rl-on and 5.2v main board side of plug. I installed a link between ext and autogen and I get the same display as above but the all the voltages are there.

Any advice would be appreciated

I didnt get any test patterns

[maxvalutech]

Re: lg 60pb660v plasma tv

With the main board completely isolated and the jumper in place you should get test patterns and screen should stay on as voltages remain stable. No test patterns indicate there are at least two faults to chase being main board not switching and display side no picture. For myself would check all connections to x and y are firmly seated, also on control board, that buffers properly reconnected, lvds straps all OK and clean, no moisture on any pads behind boards (have had sweating of these on one set), and generally assure yourself all is right to work properly when if same outcome and as previously said then y-sus is prime suspect but don't discount control board. Also does main turn on PSU with control board disconnected from main - the screen you said stayed on for a couple of seconds and this is a bit different to the y-sus problems I have seen where there is just a brief flash before turn off.