Hi all. I've been trying to revive my old Samsung LE40A856S. It's pretty old now, but it's a shame to junk such a nice TV.
About a week or two ago it just stopped working completely while watching it. Previously we've had the picture freeze and other odd things, but a power cycle has always sorted it. This time it was well and truly dead.
First thing I thought was the power supply. Opened it up and checked a few lines which should have been power, and got nothing. So I assumed it was the power board which had died, so I replaced it.
Exactly the same problem, completely dead.
So next I replaced the main board. It now comes on and the buttons respond with a beep, but nothing else happens, then it shuts itself down again with all the front lights illuminated.
I tried disconnecting the TCON board and it did exactly the same. The light on the front right (I think its the remote control active signal light) flashes a few times and the TV shuts down again.
Ok, I'd read about flashing LED's and TCON comms problems, so that was my next guess. Although the TCON was getting power, all fuses were ok, and the 3v line was present. But that was my next guess...
Ok, so new TCON board. Still exactly the same.
So I'm a bit puzzled now.
The inverter board isnt getting an enable signal, it just floats around 200mv, so it doesnt look like the main board is even trying to power up the screen.
As disconnecting the TCON makes no odds, and as far as I'm aware comms failure on the TCON does result in a flashing light on this TV (although I think its the source led), I think the board is not getting as far as communicating with the TCON.
I'm not really sure where to go from here. Any ideas much appreciated. If this TV turns out to be dead, so be it, but I'd like to learn from the experience. I'm quite capable with electronics design and manufacture in my own little hobbyist field, but trouble shooting TV's is new to me.
About a week or two ago it just stopped working completely while watching it. Previously we've had the picture freeze and other odd things, but a power cycle has always sorted it. This time it was well and truly dead.
First thing I thought was the power supply. Opened it up and checked a few lines which should have been power, and got nothing. So I assumed it was the power board which had died, so I replaced it.
Exactly the same problem, completely dead.
So next I replaced the main board. It now comes on and the buttons respond with a beep, but nothing else happens, then it shuts itself down again with all the front lights illuminated.
I tried disconnecting the TCON board and it did exactly the same. The light on the front right (I think its the remote control active signal light) flashes a few times and the TV shuts down again.
Ok, I'd read about flashing LED's and TCON comms problems, so that was my next guess. Although the TCON was getting power, all fuses were ok, and the 3v line was present. But that was my next guess...
Ok, so new TCON board. Still exactly the same.
So I'm a bit puzzled now.
The inverter board isnt getting an enable signal, it just floats around 200mv, so it doesnt look like the main board is even trying to power up the screen.
As disconnecting the TCON makes no odds, and as far as I'm aware comms failure on the TCON does result in a flashing light on this TV (although I think its the source led), I think the board is not getting as far as communicating with the TCON.
I'm not really sure where to go from here. Any ideas much appreciated. If this TV turns out to be dead, so be it, but I'd like to learn from the experience. I'm quite capable with electronics design and manufacture in my own little hobbyist field, but trouble shooting TV's is new to me.
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