The base voltage of Q230/231 is nearly identical and close to 0V. The plate output is alive (not 0 or 30V), but unbalanced. o the problem must be in the driving of the output stage.
Base-emitter voltage of Q255 is nearly 3V (-3.657 - (-6.47)), should act as a diode and be close to 0.7V. So if your measurements are correct, I conclude the transistor is defect (or not correctly connected).