E74778
Inactive User
Testing post.
LCD TV Help !!! No Picture, Sound ok
- Thread starter maarksparky
- Start date
E74778
Inactive User
Update.
Found out that the LHS inverter board (from the back of the TV) has no high voltage generated on the top 12 transformers.
Also found out that fuse F1, a 2 Amp PCB mounted fuse on the high voltage feed had blown.
Replaced the fuse with a 3 Amp fuse because it's the only one I had and then Q9 and a few other components around it started to get hot. Q9 is a 200 V Fairchild FQD7P20 MOSFET, can't read the other component markings even with a magnifying glass.
I suspect I have an issue with the circuit or transformers from 6 to 12 down on the LHS inverter board but without a circuit diagram it's difficult to say.
Having removed the MOSFET, lifted a diode D167 and disconnected the transformer outputs to the screen the overheating still persists so it's abandoned for now.
Looks like I will need to invest in a new inverter PCB but I hope it's this that's at fault because they retail at around £120 including delivery, it would be nice to be sure before investing that sort of money and then possibly finding out something else was contributing to my issue.
Alan……………..
Found out that the LHS inverter board (from the back of the TV) has no high voltage generated on the top 12 transformers.
Also found out that fuse F1, a 2 Amp PCB mounted fuse on the high voltage feed had blown.
Replaced the fuse with a 3 Amp fuse because it's the only one I had and then Q9 and a few other components around it started to get hot. Q9 is a 200 V Fairchild FQD7P20 MOSFET, can't read the other component markings even with a magnifying glass.
I suspect I have an issue with the circuit or transformers from 6 to 12 down on the LHS inverter board but without a circuit diagram it's difficult to say.
Having removed the MOSFET, lifted a diode D167 and disconnected the transformer outputs to the screen the overheating still persists so it's abandoned for now.
Looks like I will need to invest in a new inverter PCB but I hope it's this that's at fault because they retail at around £120 including delivery, it would be nice to be sure before investing that sort of money and then possibly finding out something else was contributing to my issue.
Alan……………..
E74778
Inactive User
The part number is 120V46W2B Rev13.
I have just purchased a complete Samsung TV exactly the same as mine off ebay with a phyisically damaged screen but I am told by the seller that everything else is OK, apparently the LCD is cracked and leaking ( I hope that's all that's wrong with it).
The plan is to replace the AV board, Power supply board and from the rear the LHS inverter board with the ones out of the TV off ebay.
Worst case is that it's cost me £90.00p and it still won't work :thumbdown:, best case is that the TV just works and then I will have my new one due on the 6th May for our main room and the repaired on in the bedroom :Clap:.
My eyes are starting to fail at 53 so I won't need to ask the wife what is says on the screen anymore because the text will be bigger! :Laugh:
Alan............
.
I have just purchased a complete Samsung TV exactly the same as mine off ebay with a phyisically damaged screen but I am told by the seller that everything else is OK, apparently the LCD is cracked and leaking ( I hope that's all that's wrong with it).
The plan is to replace the AV board, Power supply board and from the rear the LHS inverter board with the ones out of the TV off ebay.
Worst case is that it's cost me £90.00p and it still won't work :thumbdown:, best case is that the TV just works and then I will have my new one due on the 6th May for our main room and the repaired on in the bedroom :Clap:.
My eyes are starting to fail at 53 so I won't need to ask the wife what is says on the screen anymore because the text will be bigger! :Laugh:
Alan............
.
E74778
Inactive User
IT'S FIXED!!!!
Put in the inverter PCB from the doner TV and that cured the fault.
Thanks to everyone who gave me advice, especially Parker13.
Alan...........
Ps,
I have loads of bit's spare now, just in case.
Put in the inverter PCB from the doner TV and that cured the fault.
Thanks to everyone who gave me advice, especially Parker13.
Alan...........
Ps,
I have loads of bit's spare now, just in case.
