Matsui 1410R, Service Manual

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- Secam reference (pin 32): Pal or Secam signals are recognized using a DC level by bi-directional
communication line between this pin and pin 1 of IC7250.
-If IC7015/6C has detected a Pal signal, Vpin 32 is made 1,5V. By then the demodulated R-Y and B-
Y outputs (pins 30, 31) are applied to delay line IC7271.
-If IC7015/6C has not detected a Pal signal, Vpin 32 is made 5V. By then the demodulated R-Y and
B-Y at outputs (pins 30, 31) are not used.
-If IC7250 has detected a Secam signal, Vpin 1 IC7250 becomes low, sinking typical 150µA. current
from pin 32 (5V.) of IC7015/6C, which one detect this current to know that a Secam signal has been
detected. In this case R-Y and B-Y signals are applied to the delay line IC7271 via outputs of
IC7250 (pins 9 and 10).
This bi-directional communication line uses AC level to calibrate the 4,43MHz. between the PLL and chroma
cloche filter of IC7250.
1.4- RGB-dematrixing(IC7015/6D)
- R-Y, B-Y inputs (pins 28, 29): The R-Y and B-Y signals come from delay line (IC7271) and the Y signal
comes (internally) from IC7015/6B.
The sandcastle pulse coming (internally) from the IC7015/6E (pin 38) synchronizes RGB dematrixing and
suppresses the RGB signals during line and frame flyback.
- Video controls (pins 17, 25, 26): These inputs for contrast, brightness and saturation can be adjusted
from 0,5V to 4,5V by the µC. If beam current is limited reducing contrast with D6289 circuit.
- RGB inputs (pins 22, 23, 24): External RGB inputs come from Euroconnector and are switched by fast
blanking.
- Fast blanking (pin 21): When voltage of pin 21 is 0,4V. internal RGB is used. For a pin 21 voltage between
0,4V. and 3,5V. the set switch to external RGB.
If voltage of pin 21 is 4V. both internal and external are deleted. The up uses this status to insert RGB signals
from OSD generator directly to RGB outputs.
Fast blanking can switch signals for full screen (by a DC voltage) or for a part of the screen (by a pulse
voltage).
- RGB outputs (pins 18, 19, 20): See RGB amplifier.
1.5- Horizontal synchro (IC7015/6E)
- Start up (pin 36): When the set is switched on, voltage at pin 36 rises and when exceeds 7V. the horizontal
oscillator starts running at approx. 25 KHz. (slow start). After the line starts, main supply of IC7015 (pin 10)
comes up to 8V. and the line frequency changes to 15625 Hz.
- Standby (pin 36): This pin is used also for standby function. In this case the voltage is reduced to 3V. by
the uP and so the line is shut down.
- Hor. oscillator: This oscillator is fully integrated and internally calibrated. Frequency is obtained derived of
chroma oscillator on pin 35 of IC7015/6C.
- Hor. sync separator: This circuit (fully integrated) separates hor. pulses of CVBS proceeding from 7051/6B.
- Oscillator synchro (pin 40): Oscillator is synchronized with video signal by a first control loop circuit. The
control voltage is present at pin 39.
- Hor. phase control (pin 39): Line fly-back (pin 38) is synchronized with oscillator by a second control loop
circuit. The control voltage is present at pin 39. Phase can be adjusted by 3354.
- Hor. output (pin 37): Oscillator is converted in square wave voltage at this pin.
- Sandcastle (pin 38): This pin is used as line fly-back input and also as sandcastle output. Levels of
sandcastle pulse are 5,3V for burst detection, 3V. for line blanking and 2V. for frame blanking.
1.6- Vertical synchro (IC7015/6E)
- Vertical oscillator (pin 42): Frequency is obtained dividing frequency of chroma oscillator on pin 35
IC7015/6C. At pin 42 a sawtooth signal is present. Resistor 3342 is used to correct vertical amplitude with
beam current.
- Vert. sync. separator: It separates frame sync. pulses from CVBS and so synchronizes frame oscillator.
- Vert. drive (pin 43): This out-put is used to drive the vertical amplifier (7400)
- Vert. feedback (pin 41): this feedback is proportional to deflection current and is used to correct the vert.
drive signal.