New Project VIZIO D55-2 No Backlights..

[attainteddragon]

Re: New Project VIZIO D55-2 No Backlights..

Do you have all the voltages on the large white connector, PS_ON, ACD, 5VSB, 12V etc

you need to start at the beginning.
is ps\on present. and all other voltages.
if pfc present.is boosted pfc present if it powers on.

from the info so far, it was looking like a main board issue to me.

[budm]

Re: New Project VIZIO D55-2 No Backlights..

VIZIO D55-D2
ACD Voltage = ????, and other Voltages????

Your main board has two Boost converter circuits:
Booster #1: L8064, Q2409, D105. Check Booster output test point TP 89 (by LED connector CN8010) when TV is first turned on.
Booster #2: L8066, Q2410, D107. Check Booster output test point TP 118 (by LED connector CN8011) when TV is first turned on.
The boosted should be higher than the inout Voltage of 20V feeding the boost converter.
You have 12LED strings controlled by 12 PWM control MOSFETs (4 on the top side, 8 on the bottom side).
Pictures provided by shopjimmy.
Your main board?
http://www.shopjimmy.com/vizio-755-0...ar-serial.htm#

Power supply board: http://www.shopjimmy.com/vizio-056-0...upply-unit.htm

[Michale32086]

Re: New Project VIZIO D55-2 No Backlights..

OK Back on this.. Let me catch up..

[Michale32086]

Re: New Project VIZIO D55-2 No Backlights..

OK I did a little outside the box thinking..

Got in nice comparable SHARP yesterday.. Same type (LED, SMART etc etc) but with a cracked screen... The Main Board even had identical ports on the Main Board. At least externally..

So thinking I may have just gotten lucky, I cracked open the case. Nope.. Internally, the parts are different. Way different..

But then I noticed that both are 55" Panels.. Check the tab bond boards and the TCON and they are identical as well.

So I am thinking to myself, I think "Hmmmmmmm Might it be??"...

So I pull of the cracked panel from the SHARP and took the panel from the VIZIO (which was already tore down... Placed the panel on the SHARP. Everything lined up..

Hooked it all up and powered up.. NO joy... Scrambled red bar down the center.. Well, crap, I think.. Then it occurs to me that the TCON and the panel might be a set and have to go together. Pulled the TCON off the Vizio and put it on the SHARP...

Long story short.. (too late ) it worked!!!

Thanx for all the help on the VIZIO.. Sorry ta wastes everyone's time, but I got some good info for future VIZIO works..

Thanx again...

[Michale32086]

Re: New Project VIZIO D55-2 No Backlights..

VIZIO D55-D2
ACD Voltage = ????, and other Voltages????

Your main board has two Boost converter circuits:
Booster #1: L8064, Q2409, D105. Check Booster output test point TP 89 (by LED connector CN8010) when TV is first turned on.
Booster #2: L8066, Q2410, D107. Check Booster output test point TP 118 (by LED connector CN8011) when TV is first turned on.
The boosted should be higher than the inout Voltage of 20V feeding the boost converter.
You have 12LED strings controlled by 12 PWM control MOSFETs (4 on the top side, 8 on the bottom side).
Pictures provided by shopjimmy.
Your main board?
http://www.shopjimmy.com/vizio-755-0...ar-serial.htm#

Power supply board: http://www.shopjimmy.com/vizio-056-0...upply-unit.htm

Yep.. That's the main board..

[budm]

Re: New Project VIZIO D55-2 No Backlights..

So did you take the Voltage readings for future reference?

[Michale32086]

Re: New Project VIZIO D55-2 No Backlights..

So did you take the Voltage readings for future reference?

Yea, I can do that.. Have ta be when I come in on Tuesday....

Thanx for the info..

[Michale32086]

Re: New Project VIZIO D55-2 No Backlights..

Pulling the CN202 on the PSU to disconnect it from the main Bd. was not intended to see if you would get backlights. It was intended for you to measure the pins to see if the 20Vdc came up. With the TV off disconnect CN202 then power on the TV and measure the voltage.

I do get 24v with the CN202 disconnected from the main video board

[Michale32086]

Re: New Project VIZIO D55-2 No Backlights..

VIZIO D55-D2
ACD Voltage = ????, and other Voltages????

Your main board has two Boost converter circuits:
Booster #1: L8064, Q2409, D105. Check Booster output test point TP 89 (by LED connector CN8010) when TV is first turned on.
Booster #2: L8066, Q2410, D107. Check Booster output test point TP 118 (by LED connector CN8011) when TV is first turned on.
The boosted should be higher than the inout Voltage of 20V feeding the boost converter.
You have 12LED strings controlled by 12 PWM control MOSFETs (4 on the top side, 8 on the bottom side).
Pictures provided by shopjimmy.
Your main board?
http://www.shopjimmy.com/vizio-755-0...ar-serial.htm#

Power supply board: http://www.shopjimmy.com/vizio-056-0...upply-unit.htm

Can't find the Test Points..