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Service Manual CP-785F
When the power switch is pushed on, VIN increases slowly. During this time, C806 is charged
through R802.
As soon as VIN reaches 16V, the STR-F665X control circuit starts operating. Then, VIN is
obtained by smoothing the winding voltage which appears between pin6 and pin7 of the SMPS
transformer.
As this winding voltage does not increase to the set voltage immediately after the control circuit
starts operating, VIN starts dropping. However, as this winding voltage reaches the set value
before VIN voltage drops to the shutdown voltage (at 11V), the control circuit continues
operating (see below VIN voltage at start-up). R805 resistor prevents that VIN pin voltage varies
according to the secondary side output current.
VIN must be set higher than the shutdown voltage (VIN (off) = 11Vmax) and lower than the
O.V.P. (overvoltage protection) operating voltage (VOVP = 20.5Vmin)
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