Check all the other components related with this power transistor, particularly to the free-wheeling capacitor, connected to its collector to ground. Replace it with a new one of same capacitance value, before replacing the transistor again. Check whether there is a short circuit to horizontal winding section at the deflection coil. If LOT has any fault, BU won't last for long. Will get overheated within seconds after the set is switched ON. If you wish to get some details, check the site linked here. http://electronicshelponline.blogspot.com/ Pull up older posts.
Answers & Comments
Check all the other components related with this power transistor, particularly to the free-wheeling capacitor, connected to its collector to ground. Replace it with a new one of same capacitance value, before replacing the transistor again. Check whether there is a short circuit to horizontal winding section at the deflection coil. If LOT has any fault, BU won't last for long. Will get overheated within seconds after the set is switched ON. If you wish to get some details, check the site linked here. http://electronicshelponline.blogspot.com/ Pull up older posts.