LG 50PK590 No Display

[speedypro]

In regards to this post, I have tried everything. I get all voltages that matches on the panel (Vs etc)... all ok.

The issue is, powers on, got normal power on clicks but screen remains black. No light on panel. How do I test the ysus board?

[Hamie]

Re: LG 50PK590 No Display

just repaired one of these.

On the y-sus there are 2 resistors marked VSC and -VY. What is the voltage accross them?

Also the test points marked VZB. What's the voltage accross the 2 test points?

[Hamie]

Re: LG 50PK590 No Display

VZB is on the z-sus

[speedypro]

Re: LG 50PK590 No Display

Thanks for few pointers. I've just left work so I'll confirm tomorrow.

[speedypro]

Re: LG 50PK590 No Display

just repaired one of these.

On the y-sus there are 2 resistors marked VSC and -VY. What is the voltage accross them?

Also the test points marked VZB. What's the voltage accross the 2 test points?

VSC: 148Vdc / 0Vac
VY: 188Vdc / 0Vac

Are those correct?

[tom66]

Re: LG 50PK590 No Display

That's about right.
VZB?

[speedypro]

Re: LG 50PK590 No Display

That's about right.
VZB?

108.9Vdc

Note, When TV powers on, the screen lights up then goes out in a split of a second.

[Hamie]

Re: LG 50PK590 No Display

Check the 2 or 3 resistors on the power supply.

If it has 2 resistors they will be 22ohm 5watt
If it has 3 resistors the will be 10ohm 5watt.

You can check them in circuit.

[Hamie]

Re: LG 50PK590 No Display

Resistors located top right of the supply. Close to the z-sus connector.

[speedypro]

Re: LG 50PK590 No Display

Check the 2 or 3 resistors on the power supply.

If it has 2 resistors they will be 22ohm 5watt
If it has 3 resistors the will be 10ohm 5watt.

You can check them in circuit.

All three read 10ohms

[tom66]

Re: LG 50PK590 No Display

Does the Vs from the power supply (around 200V) stay up or collapse after the flash? What about the other voltages, Vsc, -Vy etc.?

[Hamie]

Re: LG 50PK590 No Display

If like Tom says all the voltages are staying up and not dropping.

Connect these 2 holes on the control board and disconnect the LVDS cable to the mainboard.

If you get test patterns on screen you have a bad mainboard.

[speedypro]

Re: LG 50PK590 No Display

If like Tom says all the voltages are staying up and not dropping.

Connect these 2 holes on the control board and disconnect the LVDS cable to the mainboard.

If you get test patterns on screen you have a bad mainboard.

Got test patterns. Well done. Thanks both of you. So main board is at fault. I'll see what's on eBay's.

[Hamie]

Re: LG 50PK590 No Display

You will probably struggle to get a mainboard as the are scarce.

However you will get a mainboard for a 50pk350.
The board will work (I've done it)

But the back cover will need to be modified to fit the board as it has 2 Scart connections and only 2 HDMI.

If you choose this option, It will lose the netcast and HD Freeview unfortunately.
But last I checked the 350 mainboard are only £20.

[speedypro]

Re: LG 50PK590 No Display

I know. I'll dig around and consult the customer. Thanks.

[omendata]

Re: LG 50PK590 No Display

http://www.ebay.com/itm/LG-EBT610394...item3a82d46f8d

If I dont get my 50pk590 fixed you are welcome to all the parts that are working.

[speedypro]

Re: LG 50PK590 No Display

Bringing up this post again. Do you think that if I flash this tv bios, it would solve the issue? I still have not sorted this tv...I may just keep it for personal use.

[sordids999]

Re: LG 50PK590 No Display

Whats your main board number ?
Recently stripped one these cracked screen

[lgplasma350]

Re: LG 50PK590 No Display

hello. I am new to this forum, I do not know anything about tvs. as l have been reading the above this is exactly what happened to my tv. can anybody show me a picture where the main board is. My tv is LG-50pk350. I am willing to have a go at it.

[vinceroger69]

Re: LG 50PK590 No Display

Maybe have a read of this thread too and what seems to be the problem with your set?
https://www.badcaps.net/forum/showth...hlight=50PK590