Hardware Introduction 
2-18 
 
  Voltage Waveform of U1.7 
 
In the figure of GS Voltage Waveform of Q14, the duty ratio of drive waveform varies with the 
AC input voltage. In the figure of DS Voltage Waveform of Q1, the amplitude of switch 
waveform varies with the HV output. Besides the two waveforms describes before, the 
amplitude, frequency and duty ratio of all waveforms tested during the service must be the 
same with the figures above. 
  Warning: Take extreme caution when testing and 
servicing boards to avoid damage of measurement 
devices and boards and even body injury. Never touch any 
parts on boards especially the primary circuit and the high 
voltage part of secondary circuit.
 
2.4.  Principle of the LCD   
2.4.1. Operating  Principle  of the Inverter Module   
The block diagram and functional diagram are shown in the following figures.