Le32b530p7xxc

[nezocas]

Hi,

Need some help,
Tv boots up with Samsung startup sound, I have visible image in the back ground with flasligth and also sound, But NO backligth.

On the CN801 connector from the BN44-00261B all voltages are present:
Pin 1: OFF 0v. Out of standby 1.55v
pin 3: 5.24v
pin 7,8: 13v
pin 13,16: 5.2v
pin 19: 13v
pin 21,22: 13v
pin 23: 4.46v
pin 25: 2.15v
pin 27: 0v

I have tested:
DI823 DI811 and DI810
Got both transformers out and their are 5homs apart in all the secondary windings
Replaced the FAN7530
Change place of bolth KA431 present in the board ICM845 and ICS801
Dissassembled the lcd and checked the all the U shaped CCFL´s with an ccfl tester
If I disconnect the mainboard the backligth isnt present
PFC 390v present on tha mains cap
All caps not tested with ESR meter....but they dont seem bad

Not sure what to do next

Best regards
Nezocas

[nezocas]

Re: Le32b530p7xxc

Hello,

Any help?

Regards
Nezocas

[lotas]

Re: Le32b530p7xxc

BN44-00261B schematic

[cheeky2]

Re: Le32b530p7xxc

I had one of these the other day with the same symptoms. Looking at the power board and combined inverter the transformer on one of them was burn't out on the windings.
The windings input winding around 13 ohms the two secondary windings are around 1200 ohms on an original unit and around 800 ohms on a replacement winding.
That's where I would look first.

[nezocas]

Re: Le32b530p7xxc

I had one of these the other day with the same symptoms. Looking at the power board and combined inverter the transformer on one of them was burn't out on the windings.
The windings input winding around 13 ohms the two secondary windings are around 1200 ohms on an original unit and around 800 ohms on a replacement winding.
That's where I would look first.

Hi,

As stated in my first post, the transformers winding were tested, out of circuit.....Now I dessoldered them again to write values.... didnt find much diferences between them:

1º transformer:
Primary 12.35R
1º secondary 828R
2º secondary 830R

2º transformer
Primary 12.35R
1º secondary 841R
2º secondary 841R

Not sure if this diference will make any change.

[cheeky2]

Re: Le32b530p7xxc

Then I would look at the high voltage capacitors on the output side of the inverter 5pf 6KV for breakdown. I would imagine that the feedback circuit of the high voltage side is activating for whatever reason normally as a result of failed ccfl's however you state that you have checked these. So I would check all the components that activate this circuit. You can temporarily bypass the protection circuit by inserting 82k resistor see attached picture however do not use it as a solution to your issue.
Just be extremely careful to ensure you don't use it for long as can cause fatal damage to you as a result of the very high voltages on the combined inverter psu!