While running, you can press the WHITE button to see the internal system diagnostics. This tells you the internal voltages (x 10), the internal temperature, and an estimate of the coil status (OK, NO COIL, or SHORT). If you see NO COIL or SHORT, you might want to check the coils: properly inserted, etc. But this is just an estimate and everything can still be OK even if it says SHORT or NO COIL, so do panic and call for service. If you have concerns, use the coil life tester.
While running you can also press the RED button. This will alternate between the two screens on the left. The top screen displays the model number, the firmware revision, a copyright statement, and the number of times the device has been powered ON.