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• Q5A07 conducts
• VBLNK goes High, activating CRT Protect
Flash Protect Circuit
The Flash Protect circuit in Figure 8-7 is new. It
prevents the screen from flashing by removing HV:
• If AC Power is lost.
• When switching Power from On to Off
• If the 24V supply is lost.
IC5H00 is a one shot multivibrator and monitors the
AC-OFF line. When power is lost:
• The AC-OFF line momentarily goes High.
• IC5H00 is triggered an outputs a positive
pulse.
• Q4A02 conducts pulling pin 25 of the Jungle
IC Low.
• HV is removed.
This same action occurs when Power is switched from
On to Off.
• The P-ON1 line goes Low.
• Q5F01 stops conduction.
• Q5F01 collector voltage rises.
• Q4A02 conducts removing HV.
Loss of the 24V supply has the same effect.
• Q5F02 momentarily conducts due to the
charge on C5F02.
• Q4A02 conducts.
• HV is removed.
8-7
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