EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: Skimask on April 27, 2014, 05:09:20 am
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Got a 55" Samsung TV for $0.00, didn't work.
Opened it up, found a blown cap and fuse. Replaced them. No fix. Found a guy. Sent the board out, got it back, put it in, worked. Looked at the PCB before I put it in, noticed a power transistor (right next to the blown cap of course) had been replaced. Also took my FLIR E4 to the circuit board after letting the TV run for about 1/2 hour that this particular transistor was running about 160F.
Q1) Do I dare put a small heat sink on that transistor? Taking care of course not to short out the case or anything...
Q2) Do I dare wire up a small-ish fan to push some air around in that area? Wouldn't mount it inside. I'd mount it on the outside, blow the air thru the cooling holes onto that particular transistor and pull a bit of power from the onboard USB ports.
Q3) The original transistor is a "KTD2060", triple diffused NPN power transistor. Can't buy them of course... Drilling down thru Digikey, the closest thing I can find to a sub is a 2SC4511.
Power ratings are similar, voltages are equal or greater, current ratings equal or greater. Main differences between the two are the DC current gain graphs (higher for the 2SC4511) and transition frequency (12Mhz for the 2SC4511 vs. 8Mhz for the KTD2060). I fully expect this transistor to blow again in the future, eventually. 2SC4511 suitable substitute or not? When the original transistor blows, slap the 2SC in and find out then?