Akai 21CTS92FS, Service Manual

Page: 4 / 19

3
v
li
b
re
v
b
v
p
h
v
Pin14: +8V power source supply.
Pin15: Using a capacitor of 220n in series to GND, This pin decouples the internal digital supply
oltage of the video processor and minimizes the disturbance to the sensitive analogue parts.
Pin16: PHI-2 control loop, this pin requires a capacitor at 2.2nF (C) in series to GND.
Pin17: PHI-1 control loop, the loop filter connected to pin 17 is suitable for various signal conditions
ke strong/weak and VCR signal. This is achieved by switching of the loop filter time constant
y changing the PHI-1 output current.
Pin18: GND.
Pin19: Bandgap decoupling, the bandgap circuit provides a very stable and temperature independent
ference voltage. This reference voltage (4.0 V) ensures optimal performance of the analogue
ideo processor part of the N301 and is used in almost all functional circuit blocks.
Pin20: East-west pillow signal output.
Pin21: Pin22 ： Vertical drive output.
Pin23: Pin24 ： IF input 。
Pin25: Reference current, This pin requires a resistor to ground. The optimal reference current is
100mA which is determined by this resistor. The 100mA reference current should not be changed
ecause the geometry processor is optimised for this current. Furthermore the output current of
ertical drive and EW are proportional to this current.
Pin26: Vertical sawtooth, This pin requires a capacitor to ground of 100nF
Pin27: AGC output. This output is used to control (reduce) the tuner gain for strong RF signals.
Pin28: Audio de-emphasis.
Pin29: Sound decoupling. This pin requires a capacitor connected to ground. The pin acts as a low
ass filter needed for the DC feedback loop.
Pin30: GND.
Pin31: Sound loop filter.
Pin32: AVL filter.
Pin33: Horizontal drive signal output, needs a resistor in series to +8V.
Pin34: Sandcastle output/flyback input,
Pin35: External audio input, this pin should be grounded in this chassis.
Pin36: EHT tracking/ overvoltage protection. If something is wrong, the anode high voltage rises, the
eater voltage will rise too. When the rising voltage arrive some limit, the VD461 works, the
oltage of pin 36 will exceed 3.9V, the N301will stop working.
Pin37: PLL loop filter.
Pin38: CVBS output. Monitor or RF videos can be selected.