Samsung LE32M51B S black screen

[intenzive]

Re: Samsung LE32M51B S black screen

On the input side of the CP101 I have 0.24V WTF?! Soldering a temporary bridge on the CP101 didn't do the work.

[intenzive]

Re: Samsung LE32M51B S black screen

So do you get the 12V on the input side of the fuse? The TV is on when you make the measurement?
If there is no 12V on the input side of the pin then the main board is not sending the Voltage to run the T-CON.

On the input side of the CP101 I have 0.24V WTF?!

I have this Tv and I found the fuse to give a reading of about 70 ohms, simply removing it and replacing with a temporary solder bridge rectified the issue, I'm not saying this will help you but your symptoms are pretty much what I was having.

Soldering a temporary bridge on the CP101 didn't do the work.

The blue s/n sticker to the left of the LVDS connector looks melted on one end, is there anything obvious around that area?

It looks melted because I reballed this part of the PCB.

[Dang]

Re: Samsung LE32M51B S black screen

I think you would have to say, if you have 0.25v @ V-in and 0.24v on the input side of the fuse, then this may point to an output problem with the main board, try to find which pins output the 12v feed and take some measurements, with both the LVDS cable connected and disconnected, let us know what you find, some close ups of both the front and rear of the main board would be useful.

[Dang]

Re: Samsung LE32M51B S black screen

Just out of curiosity, what was it that you reballed and why?

[nomoresonys]

Re: Samsung LE32M51B S black screen

maybe try a different mainboard.

[intenzive]

Re: Samsung LE32M51B S black screen

I am stuck guys... obviously the mainboard is not sending 12V to the T-CON... I did some measurments from the mainboard to the T-CON and the voltage is 0.24V. Do you have any idea what can cause the problem?

Just out of curiosity, what was it that you reballed and why?

I was hoping there is a loose connection on the T-CON. That is why

[budm]

Re: Samsung LE32M51B S black screen

You will need to locate the switched MOSFET that supplies the 12V to the T-CON fuse when the processor sends out the on command to turn on the switched MOSFET.
We will need really really good clear pictures around the LVDS connector on the main board to see if we can locate the MOSFET.
You should also try removing the LVDS cable from the main board and check and see if the power pins on the LVDS will have 12V.
You can also check the resistance between the chassis and the T-CON fuse to see if it shows very low resistance.

[intenzive]

Re: Samsung LE32M51B S black screen

OK. Here are some good photos of the mainboard near LVDS connector front and back:

[budm]

Re: Samsung LE32M51B S black screen

What is the P/N of that IC 805 to the right of the LVDS connector?

[nomoresonys]

Re: Samsung LE32M51B S black screen

looks like you have 5 fuses there by the connector, did you check those?

[budm]

Re: Samsung LE32M51B S black screen

Those 5 'FT' are Ferrite beads.

[intenzive]

Re: Samsung LE32M51B S black screen

what is the p/n of that ic 805 to the right of the lvds connector?

ic 805 - 9933b w548

[budm]

Re: Samsung LE32M51B S black screen

MOSFET FDS9933.
Put the LVDS cable back in place then check the resistance between either end of the SMD fuse on the T-CON against pin 1 through pin 8 to see if any one of those pins have direct connection to the fuse on the T-CON.

[intenzive]

Re: Samsung LE32M51B S black screen

MOSFET FDS9933.
Put the LVDS cable back in place then check the resistance between either end of the SMD fuse on the T-CON against pin 1 through pin 8 to see if any one of those pins have direct connection to the fuse on the T-CON.

I have direct connection between the fuse on t-con and the MOSFET on pins 7 and 8 on both sides of the fuse.

[nomoresonys]

Re: Samsung LE32M51B S black screen

Those 5 'FT' are Ferrite beads.

oh, ok, didnt think they looked like fuses.

[intenzive]

Re: Samsung LE32M51B S black screen

Oh, and someting else I measured the voltage on pins 1 and 2 and it's around 6.35V if this matters. On pins 7 and 8 which are directly connected with the fuse on the t-con I have the same voltage 0.24V

[budm]

Re: Samsung LE32M51B S black screen

OK so that FDS9933 DUAL P-CH MOSFET, and it is the switched MOSFET for feeding the B+ to the T-CON.
You also need to take the reading without the LVDS cabel connected to the T-CON to see what you have on pin 7/8 (Drain D2).
I need Voltage reading of all 8 pins when TV is OFF and when TV is ON.
Per spec sheet of the LCD panel LTA320W2-L03, the typical DCV for the T-CON is 5VDC.

[intenzive]

Re: Samsung LE32M51B S black screen

Well finally I took the measurments as you adviced me to do and here are the results:

[intenzive]

Re: Samsung LE32M51B S black screen

up

[budm]

Re: Samsung LE32M51B S black screen

up

What does that mean?