Samsung UE46EH5000W led flashes 5 times

[yoritomo]

Hello all

Model: Samsung UE46EH5000W
Main board: bn41-01795
Power board: BN44-00497A
T-Con board: BN41-01797

I could fin a picture on the net :


Unluckily i did n't find any schematic for this model.

I have a TV set with is blank screen, no backlight, when powering on the led is flashing continuously 5 times slowly .
The power supply looks working normally, i have the 13v and 5v, the main board command it to turn on as well, but no backlight at all, i could not hear any sound as well.
When i disconnect the cable from the power supply to the main board, the back light is turning on, when i disconnect the T-con board, no change.
On the main board i could find the following powers, 3.3v , 1.5v , 1.8v and a strange 0.12v on the coil L202, the one we can see under the MCU on the picture.

The customer suspects it has been a lightning strike by the HDMI then because he uses a digital decoder.

The micro-controller is getting hot

Thank you for your help

[Andrew F. Ali]

Re: Samsung UE46EH5000W led flashes 5 times

The micro-controller usually gets hot sometimes very hot when it is working and so some techs put an additional heat-sink on it. I think your T-CON Bd is attached to the Panel as the long board at the bottom side. Your PSU seems to be working. Locate a fuse to supply the T-CON Bd with power on that long board and check if you have power and if you have power on the both sides of the fuse. May be marked as F1 on the board.

[ducky29]

Re: Samsung UE46EH5000W led flashes 5 times

It cannot be repaired.Get a new mainboard

[yoritomo]

Re: Samsung UE46EH5000W led flashes 5 times

Hello, thank you for your replies.

Andrew:
The fuse is good on the T-con board, but i could find only 0.5V on it, unluckily i don't have any schematic to find where is coming this power from. The problem may occurs on the t-con board itself but if i disconnect it, i don't know where to check this power line.

ducky29
Is that not a bit early to make this conclusion ?


Edit: I found the area on the main board where it is going to the LVDS cable to provide the T-Con power, then i unplugged the LVDS cable to check, there is -4.6V on a pin of a small transistor Q201_NFRC in a 6 pin package. If i reconnect there is almost 1V.

[yoritomo]

Re: Samsung UE46EH5000W led flashes 5 times

On the fuse of the T-CON board should be 12V right ?

[mmartell]

Re: Samsung UE46EH5000W led flashes 5 times

12v or 5v depending on design.

[vinceroger69]

Re: Samsung UE46EH5000W led flashes 5 times

sounds like the tcon board has a short and loading down the voltage maybe time to check the board and see if you can locate anything getting hot or short circuit as a few people have had bad smd capacitors etc.

[yoritomo]

Re: Samsung UE46EH5000W led flashes 5 times

On one side of the small transistor i have 12V, it doe not looks like switched on by the MCU, As i could see it is 12V for this model of T-Con, disconnecting the fuse i tried to apply an external 12V with a current controlled power supply, nothing still change, the led is flashing and no backlight at all.

[vinceroger69]

Re: Samsung UE46EH5000W led flashes 5 times

so could be a mainboard fault then if not turning the backlights on and did not realise you had said its a lighting strike set

[yoritomo]

Re: Samsung UE46EH5000W led flashes 5 times

Not sure about the lightning strike, the owner said it but ...

I forgot how to turn on the t-con board in test mode, need to disconnect LVDS, to feed with the 12V panel power, and force back light on disconnecting the command of course, then it has a 5v or GND to apply somewhere on the T-CON board to display the internal test pattern, but i forgot which test point needs to be connected.

Any one knows this procedure ?

[yoritomo]

Re: Samsung UE46EH5000W led flashes 5 times

Vinceroger69

I tested all the caps on the t-con , none shorted, diodes are good too, the fuse is OK.

I still wonder about the power 0.12V coming from the regulator IC201 i don't know what should i read there, it is a missing power which may be necessary for the motherboard to work, i found 13V , 12V, 5V, 3.3, 1.8, 1.5 , perhaps a 1.2V power as i could see on some russki forums. No one know where to find this schematic to clear it ?

[Andrew F. Ali]

Re: Samsung UE46EH5000W led flashes 5 times

The transistor itself may be bad. Not sure if you can test it off the board. But I will agree with ducky29...Main Bd issue....since a lightning strike is suspected and several other components may be destroyed, continue to search for a replacement.

[ducky29]

Re: Samsung UE46EH5000W led flashes 5 times

ducky29
Is that not a bit early to make this conclusion ?

I had the same TV in my shop. Same conditions: Lightning strike and 5 flashes. Replacing the main board fixed it.

[yoritomo]

Re: Samsung UE46EH5000W led flashes 5 times

Hello

Anyway even if the transistor is bad, i tested applying the 12V panel power directly to the t-con without success, if i would have some schematics i would check with the oscilloscope the input and outputs of the MCU, but as i don't have it, i should give up and try to find a good board on the net, not always lucky, thank you for all your advice.

[vinceroger69]

Re: Samsung UE46EH5000W led flashes 5 times

i would try a replacement mainboard just get one that accepts returns if faulty and make sure it matches the lcd panel thats used in your tv other wise it may cause problems

[yoritomo]

Re: Samsung UE46EH5000W led flashes 5 times

Do you have a good website for salvaged boards in Europe ?

[ducky29]

Re: Samsung UE46EH5000W led flashes 5 times

Do you have a good website for salvaged boards in Europe ?

Check ebay, ohmsupplies, spares2repair

[yoritomo]

Re: Samsung UE46EH5000W led flashes 5 times

Thanks a lot, spares2repair i knew already but the other one looks nice too.