Sony PVM-20M4U

Question

I have this Sony PVM-20M4U pro monitor which blew the horizontal output transistor Q501 (2SD1878). I've replaced it and it seems to be working ok...exept that the transistor is getting almost hot on the heatsink. I've checked the waveforms on the base and collector and they seem to look clost to what the service manual shows.

My question is, do these transistor usually run that hot? Or is there supposedly something that's causing it to get that 'warm'?

Bob