#1
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samsung lcd tv buzzing power supply/inverter
i have this samsung tv here with a buzzing BN44-00264A power / inverter board
it came to me dead . main fuse blown fs801s 6.3a also a shorted fet qp801s qp802s ... not sure which was shorted but changed both anyway . also changed up801s for good measure ..no other apparent faulty components in the area . i haven't pulled any caps to test yet .i thought i would ask here first if anyone had any clues as to what is causing the buzzing . noise seems to be coming from lp801s . an important thing i have noticed when i plugged it into my mains power meter / conditioner i see it looking like the tv is pulling 3kw .. i dont think it can be as it would be bloody hot . if i warm up that area with hair drier the noise almost disappears and the power meter drops a lot .if i freeze cp801s and cp802s the noise starts up again ... also if i turn the back-lights down the noise lowers quite a bit . brightness affect it slightly too . tv is le40b650t2w . not that it should matter right now . manual is here ... https://www.google.co.uk/url?sa=t&rc...42059868,d.bGg p.s i am usually at audiokarma ... Last edited by petehall347; 01-02-2017 at 12:39 PM. |
#2
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well this has got stranger ... been working on it all day and getting no further ahead . mainly reflowing joints and subbing caps .
i decided to try it powered up with my variac as our line voltage is low . set variac to 240v powered the tv on .it seemed to fire up ok until the back-lights came on .then at that point my variac was sounding like a kettle boiling . at this point i switched the variac off quickly . anyone have any ideas please ? this thing is driving me nuts |
#3
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for anyone in the future this problem is now solved .
i put in another new pfc controller chip fan7530 and the supply is now silent . power draw is normal . |
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