LGOLED55B7V Clicking and dead screen.

[Donny2derby]

Re: LGOLED55B7V Clicking and dead screen.

Ok thanks Davi I will try that.

I did say that I don’t have any power at all on the P202 board which has all the 12VT and 24VD terminals on it.

And limited voltages on P201. But I will do as you ask and report back.

The board is disconnected and removed from the TV just now so I’m working on it as a bench job. I didn’t appear to have standby voltage on it when it was in situ.

Also the fact I’m not getting any voltage from certain inductors or capacitors on the primary side makes me think the issue is way before getting to the connectors for the tcon and video boards.

[Donny2derby]

Re: LGOLED55B7V Clicking and dead screen.

With a bench power supply set to 3v and negative connected to ground positive to DRV on, I get nothing. I only get a voltage drop when I connect my 3v to ground also. So there’s clearly a short on the circuit before my P201 connector which is for the main board I believe.

[Davi.p]

Re: LGOLED55B7V Clicking and dead screen.

i wonder why you tell different results in these tests, previously you had 8v at 12vm pins...

[Donny2derby]

Re: LGOLED55B7V Clicking and dead screen.

Ahh ok Davi I understand now.

I thought you wanted me to check what voltages I had on DRV ON etc not all pins.

Will test again later on and post findings.

[Donny2derby]

Re: LGOLED55B7V Clicking and dead screen.

Ok so to be clear Davi.

You want me to put 3vDc on 12VT on, DRV on and PWR on and test what voltages I have on all the other P202 pins to ground?

I’m at work in a couple of hours so will make the test as I believe you ask me to.

Do you want me to carry the test out with 240v mains plugged in or not?

[Davi.p]

Re: LGOLED55B7V Clicking and dead screen.

Answer to the second post, test both connectors, you wanna test entirely the ps board so obviously the mains in, right... remember, to minimize risks as you are not so expert, some control pins like pwr-on needs a small current so it's safer to get a small battery, or place a 2,2k or more ohm resistor in series to the bench supply.. it's an oled tv..

[Donny2derby]

Re: LGOLED55B7V Clicking and dead screen.

Ok Davi.

Connector P202. With 3.3vDC on DRV ON. There is 7.87vDC stable voltage on all 12VT pins. But completely dead on all 24VD pins.

With the 3.3vDC on 12VT on there is no voltage present at all.

With 3.3V on PWR ON. Also no voltage present at all.

Connector P201.

3.3V on DRV ON. 7.9V stable on all 12VM pins. Nothing elsewhere.

3.3V on PWR ON. There was an audible switching coming from the board immediately. On 20VS there is unstable voltage between 18v and 21v

On 12VM pins. Unstable voltage between 11&13v.

With 3.3v on 12VT ON.

Stable 7.7v on 12VS pins. Nothing on 20VM pins.

The audible switching when 3.3v was applied to PWR ON was totally new!

And there are voltages present now where I wasn’t getting them before applying the 3.3v as you asked so thanks very much for your input!

Is there hope yet haha?

[Davi.p]

Re: LGOLED55B7V Clicking and dead screen.

Bad test... i told you to make the three jumpers at same time...
12VS what it is? The unstable voltage is probably a bad contact on your jumpers..
don't hope much, a fault in ps board is much more suitable than one on screen, wait for the celebrations

[Donny2derby]

Re: LGOLED55B7V Clicking and dead screen.

Ok so I need 3.3vDC on PWR ON, DRV ON & 12VT on at the same time!!?

Yet you don’t sound so confident I’m going to get a success at all!

12VS is 7.7v stable.

[Davi.p]

Re: LGOLED55B7V Clicking and dead screen.

Yes at the question. 12VS doesn't exists if i'm right..

[Donny2derby]

Re: LGOLED55B7V Clicking and dead screen.

Yes Davi you are correct there is no 12VS

[Donny2derby]

Re: LGOLED55B7V Clicking and dead screen.

Davi something amazing has happened!

With those 3 pins linked and 3.3v applied all voltages on both connectors are present and stable!

This is exciting! What next?��

[Davi.p]

Re: LGOLED55B7V Clicking and dead screen.

Next i will try to make you do a screen test, remove the ribbons from main board to tcon bd, then with the 3 jumpers in place turn on current and watch if a video test starts, if you can film it... or photograph..

[Donny2derby]

Re: LGOLED55B7V Clicking and dead screen.

Ok Davi that’s great thanks.

I’m at work tonight so will try that tomorrow morning when I get up.

If this works and the TV is fixed we will get married and have babies together haha!

[Davi.p]

Re: LGOLED55B7V Clicking and dead screen.

Bleahhh!!!!

[Donny2derby]

Re: LGOLED55B7V Clicking and dead screen.

Does the fact that the voltages are all correct with the jumpers in place prove the power board is ok then Davi?

The fault could be coming back from the tcon?

And can you tell me what I should be observing during the screen test.

I’ll look on YouTube to see if I can find an example as well.

[Davi.p]

Re: LGOLED55B7V Clicking and dead screen.

1) is ok
2) i don't understand, back to what??
3) usually are screen filled with 1 colour and cycling colours.. you must check uniformity, don't be so doubtful, do it and see

[Donny2derby]

Re: LGOLED55B7V Clicking and dead screen.

Ok Davi the screen test has not performed well.

There is no change of image on screen. It remains black. There is an audible sound of a relay and 3 blinks of a the standby LED (approx 1 second intervals) then the relay switches again and no further change of state on screen.

[Davi.p]

Re: LGOLED55B7V Clicking and dead screen.

Sorry my mistake, you have to leave alone the main board if not the three jumper doesn't take effect, so detach it..

[Donny2derby]

Re: LGOLED55B7V Clicking and dead screen.

Ok Davi now I just have the power board plugged in and nothing has taken effect.

There is no ribbon cable to main board or tcon only the 3 jumpers in place.

Now I get nothing at all.

But I wouldn’t expect to surely? With no ribbon cables to either main board or tcon there can’t be an expectation to get an image on screen because there’s no 12 or 24v going to either board.

Have we got our wires crossed in translation here Davi?

Yes Davi my mistake. The ribbon cables from main board to tcon remove. The jumper cables from power board to tcon remain in yes!!??

Ok edit number 3. The same result. No change in state of the screen. An audible relay switching. The remote control knows it’s being used as the red power button illuminates when I press it but no LED standby light comes on and there’s nothing to observe on the screen at all.