Pioneer PN50951-22U Backlight On, No Image

[x_orange90_x]

I get backlights that stay on not there is no image. The tv does not automatically power on when plugged in either which I generally see happen when there is a fault. It responds as it should to the power button.

I checked the test points on the TCON and I have proper voltages except for at 1P15V. I don't know if that is supposed to be 15V or 5V, but either way I only get 1.134V on that point. I have 12V, 8V, VCC, and a small amount on the CKV point.

I tried heating up the SoC on the main board but that made no difference. Disconnecting either ribbon from the TCON also makes no difference.

[EazyBone]

Disconnect one ribbon from tcon to panel at a time and see if you get half image

[x_orange90_x]

Disconnect one ribbon from tcon to panel at a time and see if you get half image

That was the last thing I said in my post. No difference. I reseated the lvds ribbon too.

[lotas]

I wonder where the supply voltages VGH, VGL, VCOM, AVDD are...

[lotas]

At this test point there is 1.8v?
1P15V - 1.15V

[x_orange90_x]

At this test point there is 1.8v?
1P15V - 1.15V

1P15V - 1.123v
12V - 12v
VCC - 10.32v
SCL -3.28v
SDA - 3.27v
CK2-TCON - 1.356v

Those are the only labeled points I see besides TEST and that starts out negative mV and slowly rises into the positive mV.

[lotas]

1P8V -- 1.8V ?

[x_orange90_x]

1P8V -- 1.8V ?

Oh sorry. In my first post when I said 8v was 8v that was the point I meant. So 1P8V - 8v

[lotas]

Why 8v and not 1.8v.
3P3V - 3.3V
1P8V - 1.8V
1P15V - 1.15V

[x_orange90_x]

Why 8v and not 1.8v.
3P3V - 3.3V
1P8V - 1.8V
1P15V - 1.15V

I will recheck it.

[EazyBone]

That was the last thing I said in my post. No difference. I reseated the lvds ribbon too.

I see that now whoops, read differently.

[x_orange90_x]

Why 8v and not 1.8v.
3P3V - 3.3V
1P8V - 1.8V
1P15V - 1.15V

3P3V - 3.25v
1P8V - 1.78v
1P15V - 1.14v

[lotas]

3P3V - 3.25v
1P8V - 1.78v
1P15V - 1.14v

Well, everything matches, now we need to get to the buffer strips and see what is soldered on them...

[x_orange90_x]

I noticed there's a buzzing that comes from the main board when the power is off but plugged in, and it turns into a lower hum when power is on. It comes from the lower part of the main.

[x_orange90_x]

Well, everything matches, now we need to get to the buffer strips and see what is soldered on them...

What would the chances be that something is wrong on ONE of them that causes both sides not to work, or something being wrong on BOTH sides? I get zero image on either side with TCON ribbons removed, alternately.

[lotas]

Your second part of the t-con is soldered to the strip, where all the main voltages for powering the panel are formed.

[Diah]

its is MB issue.. check after the soc low voltage id there TESTED OK--- WE HAVE IN THIS FORUM SAME ISSUE:: ::

[lotas]

https://www.badcaps.net/forum/troubl...50951-22u-dead

[x_orange90_x]

I reviewed that thread before making my own post. I have backlights though so my issue is somewhat different I think. Nonetheless I'm still suspecting the main board. Is there anything I can/should check on the main?

[x_orange90_x]

Your second part of the t-con is soldered to the strip, where all the main voltages for powering the panel are formed.

I looked at the strips and see several more test points, but didn't see VGH, VGL, etc. I did see VCC however. I will recheck later today when I am home.