Crown Pulse 2X1100 Supplementary Manual page 10

6. Move the probe to monitor the waveform at the IGBT's marked E on Diagram 2. You should see a switching waveform
similar to that shown below.
7. Some examples of incorrect waveforms are shown below, along with the likely area of failure.
The waveform below is commonly caused by faulty ZTX650-ZTX750 transistors in the power supply.