Service manual

Figure: Standby supply circuitry
To apply this on the N8 (diagram A2): replace switch 'S' by FET TS7102, coil L by
L5101, diode D by D6111 and C by C2104.
Time interval t0 - t1:
After switching the set on, the gate of MOSFET TS7102 will be high (max. 15V due to
zener diode D6105). This will drive the FET into saturation (UDS = 0V). The DC-voltage
UMAINS will be transposed across the primary winding of L5101 (Pins 3 & 5) resulting
in a linearly increasing current through this coil.
The voltage across the co-coupled coil (Pins 1 & 2) is also positive and will keep the
FET into conductivity via C2101, R3103, R3105, R3102 and R3117 for some time. The
slope of the primary current is determined by the self-induction of the coil and on the
magnitude of the supply voltage (+375 V).