Samsung LED/LCD model UA40C6200U

[snuggles]

Hello all,
My tv won't turn on.Power led solid red when ac supply connected.Starts flashing with audible relay clicking when turned on via remote.

I have read quite a few threads on here.My question is, with this model /sereis ( C) ,should the backlights come on with the connector lead between the mainboard and power supply disconnected? Or do I need to connect A5v to BL_ON

Am i correct in assuming BL_ON is a command line, and not a confirmation line.
Also P_DIM is a led supply dimming command?
I have checked for backlight operation by connecting LED- to ground,altough not full brightness,all series leds appear to light up.

The power supply used is a BN4400357A

I have standby 5v dc stable, and other voltage rails pulsing.Ther is also 160v on the led supply pins.

I am trying to isolate whether ai have 1 or more faulty boards.
Thanks,Robert

[budm]

Re: Samsung LED/LCD model UA40C6200U

BN44-00357A has pull-up resistor for the PS_ON and the BL_ON, the transistors on the main board will keep these two signal lines LO, it will release these two line to go HI when TV is ON. So if you disconnect the cables between the main and the Power supply board, the backlights should come on, and the PFC Voltage booster circuits to come on also.
If you do have backlights then the problem is in the main board is not allow those two signals to go HI.

[snuggles]

Re: Samsung LED/LCD model UA40C6200U

Thank-you for advice,and the psu schematic. This is also my understanding with the "C" series as well.
Disconnecting the 18 wire lead from the mainboard and reconnecting the ac supply produces nothing,which would indicate a faulty power supply.

However, connecting A5v to PS_ON and BL_ON produces backlights and led supply boosted to 188v.Also 12v and another 5v supply present.

Does this still indicate a faulty power supply?

[budm]

Re: Samsung LED/LCD model UA40C6200U

OK, I just look at the diagram again, the pull-up resistor (RB852) for the PS_ON is not used, that is why you have to use the external source to turn on the power supply. So it seems to me that the main board is not sending the PS_ON signal to turn on the power supply, it is the main board problem at this point.

[tibimakai]

Re: Samsung LED/LCD model UA40C6200U

I had/have two 46/40C6300 TV's with constantly clicking on and off relays and both had/have mainboard issues.

[snuggles]

Re: Samsung LED/LCD model UA40C6200U

Thank-you very much for your help.I had read that the mainboard was the achilles heel of this model

Samsung's policy of only selling replacement parts to their ASC and the price in New Zealand, make this an uneconomic repair.Even with just the main-board.
Unfortunately the main board appears to non-existant using most search engines

Power supplies.T-Con seem universal within model ,however main-boards appear to be country/market specific.

Once again, many thanks.

Cheers Robert.

[mmartell]

Re: Samsung LED/LCD model UA40C6200U

Maybe a long shot but try heating the main ic with a hair dryer. If it's faulty maybe you can attempt a reflow until a replacement board becomes available.