Sharp DA-50W chassis, problem with horizontal output stage

[torbjorn]

Horizontal output transistor Q601, BUH515 was shorted and resistor RA611 showed signs of overheating. Both those components were replaced and several bad solder joints repaired. When switching on the set, it worked normally for 1-2 minutes, then Q601 failed again. Q601 does not get hot prior to failing. A suggestion from another forum was that this could be caused by insufficient base drive to Q601 due to a bad C607. This capacitor has been replaced without success.
A strange thing is that the set runs so well before Q601 fails. If it had been, for example, a flyback capacitor problem, then the picture width would not have been correct and it would probably have shown E/W distortion.

[bbp1]

Check/change LOPT!I assume you have checked everything elseB+, electros, djs etc. And not to forget yoke.