it would be good to get an original transistor, there are transistors that are sold in stores that bring the same number we are looking for but are different from the original because sometimes they bring the damper diode and sometimes not, of course there are TV models that use TSH without damper but it seems that it should take then make sure you bring it, otherwise check the RF capacitors those that are close to the fly back and leave with the TSH collector, if after reviewing these capacitors they are fine you would need to check if the source is delivering the correct voltage to the fly back, check the state of the yoke if it is short that may be the cause and finally the cause could also be the fly back.