Got this TV in the other day, was set out by the owner as dead, figured i would take a stab at fixing it since its in nice shape otherwise. Here is what i know and have tried..
Plug in the power cord and the blue LED on the front comes on for about 5-6 seconds then goes off. Will not turn on with the side button or the remote.
Took it apart checked the power supply, there is 5v standby, showing 4.97v there, the 12v and 24v rails are dead, no output, not even a brief showing of voltage when plugging it in or trying to turn it on.
Checked all the caps on the secondary side with my ESR tester, a few were iffy, only one had a very very slight bulge to the top, so i got out my assortment of Nichicon's that i always keep on hand, i fix a lot of LCD monitors, and i repopulated the board, replacing the caps in the secondary rails. The caps on the primary side all tested good no problems.
Tried it again, still the same results. So i checked the Mosfet's, there is two 12N50T's and two K3568's, one of the 12N50T's tested as bad, the other passed, the K3568's were totally dead. Since they aren't a commonly available part i crossed them to TK12A50D's as recommended replacements. Ordered them and got them today and replaced all of them, tried the TV again and still the exact same behavior as before!!
I'm stumped, i can't find any info on this power supply board online so i'm trying to trace things out, but so far i'm coming up with nothing. There is a single IC on there, IC001, which is a VIPer22A that i was thinking of replacing since its a cheap part, but otherwise i don't know what else to try.
The Bridge Rectifier is fine, and seeing voltage across the primary cap, so now i'm going to pull it back apart and trace out the connections to the IC and see if that's the failure.
Any other suggestions??
Plug in the power cord and the blue LED on the front comes on for about 5-6 seconds then goes off. Will not turn on with the side button or the remote.
Took it apart checked the power supply, there is 5v standby, showing 4.97v there, the 12v and 24v rails are dead, no output, not even a brief showing of voltage when plugging it in or trying to turn it on.
Checked all the caps on the secondary side with my ESR tester, a few were iffy, only one had a very very slight bulge to the top, so i got out my assortment of Nichicon's that i always keep on hand, i fix a lot of LCD monitors, and i repopulated the board, replacing the caps in the secondary rails. The caps on the primary side all tested good no problems.
Tried it again, still the same results. So i checked the Mosfet's, there is two 12N50T's and two K3568's, one of the 12N50T's tested as bad, the other passed, the K3568's were totally dead. Since they aren't a commonly available part i crossed them to TK12A50D's as recommended replacements. Ordered them and got them today and replaced all of them, tried the TV again and still the exact same behavior as before!!
I'm stumped, i can't find any info on this power supply board online so i'm trying to trace things out, but so far i'm coming up with nothing. There is a single IC on there, IC001, which is a VIPer22A that i was thinking of replacing since its a cheap part, but otherwise i don't know what else to try.
The Bridge Rectifier is fine, and seeing voltage across the primary cap, so now i'm going to pull it back apart and trace out the connections to the IC and see if that's the failure.
Any other suggestions??
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