Samsung UN55HU6840 No picture has sound and backlights

[dskall]

Re: Samsung UN55HU6840 No picture has sound and backlights

[dick_barton]

Re: Samsung UN55HU6840 No picture has sound and backlights

Thanks for the info.
So it looks like the Tcon is a 3.3V Tcon. What voltage is on pin 4 when you switch on and when you bring it out of standby?

[dskall]

Re: Samsung UN55HU6840 No picture has sound and backlights

Don't see how 55" could run off 3.3v. Looks like maybe trace runs to ic2602? 2802. Also see a 13v panel on legend.

[2smoovedaddy]

Re: Samsung UN55HU6840 No picture has sound and backlights

Looks like 4485D maybe you can make it out. Had to magnify it to see it.
Voltage on first 4 pins is 12.76 and 0 on the last 4.
Sorry didn't see it had been posted already.

[dick_barton]

Re: Samsung UN55HU6840 No picture has sound and backlights

OK so it looks as though its a 12V supply to the Tcon. Can you measure the resistance from pins 5,6,7 or 8 to 0V (ground) with the set off and meter set to ohms.

I suspect the chip is blown and is not switching the 12V input at pins 1,2 &3 to output pins 5,6,7 & 8 when Pin 4 goes to 12V

[2smoovedaddy]

Re: Samsung UN55HU6840 No picture has sound and backlights

All open(OL). By the way thanks for all you guys help.

[dick_barton]

Re: Samsung UN55HU6840 No picture has sound and backlights

If the resistance on the output pins 5,6,7, & 8 is high then it does not look like a short circuit causing the problem so I suspect the IC to be at fault.

[dskall]

Re: Samsung UN55HU6840 No picture has sound and backlights

I would replace it their inexpensive. It's a 4435 P-Channel 30-V MOSFET SOP-8

[2smoovedaddy]

Re: Samsung UN55HU6840 No picture has sound and backlights

Will do I'll keep you posted on the results.