Samsung LE26r71b power supply issue. Any thoughts ?
Greetings fellows, this is my first ever post here asking for help, so please don't be too rough on me if I mess anything up 
)
So I've got this small Samsung TV (model LE26r71b) with a bad power supply. The power supply board is a BN96-03058a (the one in the first picture - hope you guys can see it). I've repaired several of these before and all of them had either bad caps (the irony), or the IC in the second picture gone bad (or, of course, a combination of both). The IC is a F9222L and it's a pretty obscure thing, as I couldn't find a detailed datasheet about it. I do know that's it basically two MOSFETs with a control IC built it. On all of the supplies where I've encountered this F922L so far, the problem was the classic flashing red light or a completely dead set (blown mains fuse due to one of the FETs in the F922L becoming shorted, sometimes taking out the mains rectifier with it).
Replacing the F922L fixed the issue every time, however, the symptoms on this one are quite different: the set doesn't turn on (duuh), but the power light doesn't actually flash, it sort-of FLICKERS accompanied by a rhythmic whistling sound, indicating that the PSU is trying to power on but can't...strange.
Taking some basic measurements showed that the 5VSb line is Ok....and that was about it, since applying those 5 volts to the ON/OFF pin produced the same result: whistling sound and no power to the 12V rails (inverter and main board were disconnected). I checked the diodes in the secondary side for shorts and they all reported fine. So did the KIA278R and the 33167t (both in the upper left of the board: the KIA is a 12v voltage regulator and, while not showing any shorts, I can't exactly check whether it's working or not, since the 12V rail doesn't show any sign of life (the transformer is not supplying anything to the secondary). The 33167t is a transistor and it's part of what I'd identify as a buck converter that produces the 5Vsb, so that's definitely working. Now my question is: could this defect be caused by the F922L ? It's a fairly expensive part, so I wouldn't want to get it and realize it's not that (TVs not mine btw). I know there's a whole lot of other parts that can go bad on a SMPS, but maybe someone else has had this particular issue before and can at least guide me. I must admit, I haven't fully checked the PFC section, so maybe you could give me some pointers there too. Sorry for the wall of text, but I wanted to give as much info as possible. Cheers
)So I've got this small Samsung TV (model LE26r71b) with a bad power supply. The power supply board is a BN96-03058a (the one in the first picture - hope you guys can see it). I've repaired several of these before and all of them had either bad caps (the irony), or the IC in the second picture gone bad (or, of course, a combination of both). The IC is a F9222L and it's a pretty obscure thing, as I couldn't find a detailed datasheet about it. I do know that's it basically two MOSFETs with a control IC built it. On all of the supplies where I've encountered this F922L so far, the problem was the classic flashing red light or a completely dead set (blown mains fuse due to one of the FETs in the F922L becoming shorted, sometimes taking out the mains rectifier with it).
Replacing the F922L fixed the issue every time, however, the symptoms on this one are quite different: the set doesn't turn on (duuh), but the power light doesn't actually flash, it sort-of FLICKERS accompanied by a rhythmic whistling sound, indicating that the PSU is trying to power on but can't...strange.
Taking some basic measurements showed that the 5VSb line is Ok....and that was about it, since applying those 5 volts to the ON/OFF pin produced the same result: whistling sound and no power to the 12V rails (inverter and main board were disconnected). I checked the diodes in the secondary side for shorts and they all reported fine. So did the KIA278R and the 33167t (both in the upper left of the board: the KIA is a 12v voltage regulator and, while not showing any shorts, I can't exactly check whether it's working or not, since the 12V rail doesn't show any sign of life (the transformer is not supplying anything to the secondary). The 33167t is a transistor and it's part of what I'd identify as a buck converter that produces the 5Vsb, so that's definitely working. Now my question is: could this defect be caused by the F922L ? It's a fairly expensive part, so I wouldn't want to get it and realize it's not that (TVs not mine btw). I know there's a whole lot of other parts that can go bad on a SMPS, but maybe someone else has had this particular issue before and can at least guide me. I must admit, I haven't fully checked the PFC section, so maybe you could give me some pointers there too. Sorry for the wall of text, but I wanted to give as much info as possible. Cheers
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