Re: Samsung 193v backlight doesn't stay on
I used ccfl's that had been removed from another screen, so I could see the individual tubes and determine which bulbs were not lighting up. I connected these ccfls to all 4 connections and they would stay lit so I could easily tell which lamp wasn't lighting and therefore which transformer was bad.
A couple of points if you aren't able to do the above test - you have to have all 4 connectors connected to ccfl's, or it will turn off. Try connecting 3 wires from the original lcd and one from the external lcd (always use the same connector on the external one - as it is possible that one of those tubes could be bad), and test it, noting if the external lamp came on. Then move the external lcd connection to the next connection, reconnect the original, and test again, doing this at all four connectors. Then you should be able to determine if one or more of the transformers are bad. I usually only had one bad per board, but occasionally there were two that were bad. Also check the board in the inverter area. If you have dark spots above the components labeled U2 -U4 it is possible they are damaged, and replacing the transformer will not solve the problem.
After working on this model I ordered a Blue Ring Tester from Anatek and it is very nice for determining if a transformer is good or not.
I used ccfl's that had been removed from another screen, so I could see the individual tubes and determine which bulbs were not lighting up. I connected these ccfls to all 4 connections and they would stay lit so I could easily tell which lamp wasn't lighting and therefore which transformer was bad.
A couple of points if you aren't able to do the above test - you have to have all 4 connectors connected to ccfl's, or it will turn off. Try connecting 3 wires from the original lcd and one from the external lcd (always use the same connector on the external one - as it is possible that one of those tubes could be bad), and test it, noting if the external lamp came on. Then move the external lcd connection to the next connection, reconnect the original, and test again, doing this at all four connectors. Then you should be able to determine if one or more of the transformers are bad. I usually only had one bad per board, but occasionally there were two that were bad. Also check the board in the inverter area. If you have dark spots above the components labeled U2 -U4 it is possible they are damaged, and replacing the transformer will not solve the problem.
After working on this model I ordered a Blue Ring Tester from Anatek and it is very nice for determining if a transformer is good or not.
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