Samsung LE40C535 dead. Backlights on when disconnecting mainboard.

[SirBlaBla]

Hi

I have This Samsung TV, whith the following spec.:
Model: LE40C535F1W
Type: LE40C535

Power Supply
Model: I40F1_ADY
CODE: BN44_00340B

Mainboard:
BN41-01331B 2010.02.10 (on top of PCB)
BN94-02616K 2010.06.09 F098(P08) (On sticker on PCB)

When I plug 230V AC to it, and try to turn it on, nothing happens. It's totally dark, and will not switch on.



Backcover off:

I measure the following on the Power Supply, when:

Nothing is connected to the Power Supply.
=====================
Connector: CN802 (The one to the Mainboard)
1,3,5: (B13V) 12,7v
2: (5V_DET) 0,0v
4: (BLU_ON) 2,0v
6: (E-PWM) 5,1v
8: (H_SYNC) 0,0v
7,9,10,12: (GND) OK
11,13,14: (B5V) 5,3v
15,17: (B13V) 12,7v
16: (A5V) 5,3v
18: (PS_ON) 1,5v

Connector: CNI802 (To the backlight)
1: (B12V) 12,7v
2,3: (FB) 0,0v
4,5: (GND) OK
6,7: (LD) 0,0v


Only CNI802 and CNI801 (Backlight) are connected to the Power Supply.
(Backlight turns on)
=================================================
CN802 (The one to the Mainboard)
1,3,5: 12,7v
2: 0,0v
4: 2,0v
6: 5,1v
8: 0,0v
7,9,10,12: GND = OK
11,13,14: 5,3v
15,17: 12,7v
16: 5,3v
18: 1,5v

CNI802:
1: 12,7v
2,3: 0,0v
4,5: GND = OK
6,7: 11,6v

Everything is connected to the Power Supply.
(Backlight turns off again and not possible to start TV)
========================
CN802 (The one to the Mainboard)
1,3,5: 0,0v
2: 0,0v
4: 0,0v
6: 0,0v
8: 0,0v
7,9,10,12: GND = OK
11,13,14: 0,0v
15,17: 0,0v
16: 5,3v
18: 0,0v

Connector: CNI802 (To the backlight)
1: 0,0v
2,3: 0,0v
4,5: GND = OK
6,7: 0,0V

I measure the following on the Mainboard, when everything is connected to it.
(Image shows what I measure on the bottom side test points of the Mainboard)

Since it seems that the problem is on the mainboard, and I can't find a diagram online, I was wondering if you could help me with some guidance og perhaps a diagram of the mainboard ?
Or where I can buy it online?

[budm]

Re: Samsung LE40C535 dead. Backlights on when disconnecting mainboard.

The problem is on the main board. There are 3-pin voltage regulator ICs on the main board that you should check the input and output voltages, that will be a start. Also try heating the board with hair dryer to see if it will start up.

[SirBlaBla]

Re: Samsung LE40C535 dead. Backlights on when disconnecting mainboard.

Hmm... Thanks
Then I'm of on a treasure hunt for 3-pin voltage regulators. Will be posting back negative or positive results.
I'll also try heating the board.

[budm]

Re: Samsung LE40C535 dead. Backlights on when disconnecting mainboard.

Read this post first:
https://www.badcaps.net/forum/showth...999#post300999

[SirBlaBla]

Re: Samsung LE40C535 dead. Backlights on when disconnecting mainboard.

Yes, I saw your post regarding "Voltage Regulator (LDO) testing"

I'v found some output Voltage which is shorted to ground on three of the 3-pin voltage regulators. I'v tested some capacitors and removed some, but I can not find the right one.
Anyone got a diagram of the board?

[SirBlaBla]

Re: Samsung LE40C535 dead. Backlights on when disconnecting mainboard.

But when I can't see where voltage to the different voltage regulators is supposed to come from, how can this help?
There are so many IC's which are missing voltage.

Anyone here who has a print layout/diagram of this main board or know where I could get it (buy it)?

[Electrocut]

Re: Samsung LE40C535 dead. Backlights on when disconnecting mainboard.

Hi!

I was having the same symptoms on my LE32C450. The standby voltages was as good as you, but the red standby LED was off.

For me, the Serial Flash content (IC402) was corrupted. I restored the content using a self made SPI flash programmer (Raspberry Pi with flashrom software installed on it).

See this thread.

[steviewonder]

Re: Samsung LE40C535 dead. Backlights on when disconnecting mainboard.

Seconded.A very common issue,is flash spi becoming corrupt.
Available at Ohm supplies!