50pt350

[fixerupper75]

I have this LG 50Pt350. It has standby light but i press the power on no picture.
I want to know what is ctrl_0E and what is the voltage on that pin.

[fixerupper75]

Re: 50pt350

I measured the va and vs voltages.

va 120vac
vs 450vac
Any suggestion?

[sordids999]

Re: 50pt350

you need to measure in DC then look at the panel sticker to see if VS/VA match up etc etc

[dick_barton]

Re: 50pt350

Those voltages are roughly double what they should be. Are you sure your meter is reading correctly. Have you measured some of the low dc voltages to see that your meter reads them correctly. CTRL_OE possibly "Control Output Enable" but just a guess.

Edit
+1 Sordids999 missed the "ac"

[fixerupper75]

Re: 50pt350

sordids999 thanks, vdc 200 vs and 53 va

[dick_barton]

Re: 50pt350

Slightly low but I don't think enough to stop it working. There will be other voltage test points on the boards. Vsc, VE etc. Can you find and measure the dc voltages at those points.

[ReeceyBurger123]

Re: 50pt350

On Lgs Ve is Zbias.

[fixerupper75]

Re: 50pt350

the vsc voltage is bouncing from 0 to 202.
vzbis 88

[ReeceyBurger123]

Re: 50pt350

Ysus or buffer issue then, remove buffer modules one at a time (upper first then lower) and and restest Vsc you might even get an image if one of the buffers is short and you remove it on one half of the screen.

[fixerupper75]

Re: 50pt350

Shouldn't there be two relays that click when you turn the set on?

[ReeceyBurger123]

Re: 50pt350

You have Vs meaning relays have turned on the fault is with Ysus or buffer.

[fixerupper75]

Re: 50pt350

Ok, I think it is the ysus and not the buffer. Cause the voltage still bounced around with the upper and lower buffers removed.
Thanks for your help.

[fixerupper75]

Re: 50pt350

Reeceyburger123, can you answer what is ctrl_0e it run from the control board to the ysus? I don't have any voltage at that pin.

[fixerupper75]

Re: 50pt350

Replaced the ysus board and there was a puff a smoke coming from lower buffer. still no picture top or bottom.

[fixerupper75]

Re: 50pt350

bump

[ReeceyBurger123]

Re: 50pt350

Ok so the buffer want bang with a replacement Y sus ? Keep both buffers out and recheck Vsc, what is that voltage doing ?

[fixerupper75]

Re: 50pt350

On the power board, fuses F302, F801 has bouncing voltage. Fuse 101 120vac.
Everywhere 15vdc is suppose to be Im getting a reading of 18.5.

[fixerupper75]

Re: 50pt350

with buffer removed the voltage is still bouncing.

[ReeceyBurger123]

Re: 50pt350

What about with the Ysus disconnected ? What does Vs do ?

[fixerupper75]

Re: 50pt350

hey the vs test point and va test point on the pbd never balanced. va 55vdc and vs 205vdc