— 33 —5-5. Power down detection circuitIC48 : Detection ICThe power is supplied at CN16 from switching power supply unit.When the VP voltage become more than 22V, the voltage appears at pin No.2 of IC48 throughthe zener diode ZD2.The detection IC outputs "High" signal from pin No.6 and its signal going to IC45.Then, the signal "INTPWD" becomes "High" and going to GA2.The GA2 outputs "Reset" signal and reset the all GAs.