Matsui 1410R, Service Manual

Page: 32 / 39

4.3- Protections
- Overload protection (pin 2): This is produced if T-on is increased till Vpin 2 voltage reaches the foldback
point (see signals 4.5). The IC will switch into overload mode (off and on continuously).
- Output voltage protections (pin 6): Limiting values of Vpin 6 voltage (7.25 and 16V.) provide under and
overvoltage protections for the circuit.
- Mains overvoltage (pin 3): The voltage at pin 3 IC7515 is a measure for the mains voltage and so the DC
voltage across C2505. As soon as the voltage Vpin 3 reaches 6.6V. the supply will stop running.
4.4- Secondary side
- Line supply: The value to adjust the supply is 101,5V. for 14" CPT’S, 102,5V. for 17" CPT’S and 107V. for
20"/21" CPT’S. This supply is also used to obtain the +33V. varicap voltage by D6602.
- Auxiliary supply (+11V.): This supply is used for sound output amplifier, for start up the line circuitry and
for the stand by of the microprocessor. +5STB is regulated by T7525 and D6575. A +5V. power on reset
signal (POR) is obtained during start up by R3573 till T7571 conducts by D6570.
4.5- Power supply signals
V cont
V pin 5 = V GS (7525)
I DS (7525)
V DS (7525)