'Active Off' And 'Suspend/Standby' Operation - Sony CPD-420GS Training Manual

'Active Off' and 'Suspend/Standby' Operation

The power supply enters the 'Active Off' and 'Suspend/Standby' mode
under the following conditions...
1. Loss of H and/or V Input Sync signals
· LED illuminates Orange
2. Loss of Horizontal Deflection feedback
· LED illuminates Orange (1.5 seconds) / Off (0.5 seconds)
3. Loss of Vertical Deflection feedback
· LED illuminates Orange (1.5 seconds) / Off (0.5 seconds)
4. If Beam current (ABL) becomes excessive
· LED illuminates Orange (0.5 seconds) / Off (1.5 seconds)
5. If HV becomes excessive
· LED illuminates Orange (0.5 seconds) / Off (0.5 seconds)
6. Loss of secondary voltages
· LED illuminates Orange (0.5 seconds) / Off (0.5 seconds)
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The 'Active Off' and 'Suspend/Standby' modes are controlled by the 'RE-
MOTE ON/OFF' signal from the Micro IC1001/7 (N Board). Feedback is
provided by circuit elements IC603, D631, D632, R662, Q656 and Q658.
During 'Active Off' and 'Suspend/Standby' modes, the 'REMOTE ON/OFF'
signal from IC1001/7 is L (0V) and is applied to Q656 turning it OFF, thus
turning Q658 on to disable IC652. Current flows through Q658 (E - B),
R662 and D632 biasing Q658. This allows standby current to flow through
IC603 pin 1 and pin 2, D631 and Q658 (C - E). The output of IC603/4
outputs sink current from IC601/9 (FB). As a result, IC601/6 responds
accordingly to adjust the duty cycle and frequency output applied to Q602
in order to produce the reduced unregulated output voltages.
IC601/6 PWM
Q602/Drain