Chigo CS-25V3A-MA114A, Service Manual

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d), if all above are normal,then replace the main chip.
(2) display bad or indicator light does not shine
Showing bad or light does not shine
a), check whether the voltage of display board is normal (5V);
b), check whether the resistance of display lamp is normal(light-emitting diode forward resistance is a
few hundred ohms,)
c), check whether chip is cold solder joint, short circuit, or replace the chip.
(3) Buzzer does not ring or abnormal:
a), check whether the voltage of Buzzer is normal(about 12V),if normal,then check the next step ;
b), check whether the Buzzer is noiselessly..
(4) Not receive or receiving is insensitive
a), check whether the wire of receiver is normal, or replace the connecting wires;
b), check whether the voltage of receiver is normal(5V), or check the power supply circuit;
c), check whether the receiver is normal.if normal,check whether the main chip is normal, otherwise,
replace it.
(5) sensor failure
a), check whether the voltage of room temperature sensor and pipe temperature sensor is normal (make
sure at the same temperature conditions,the voltage difference between these two sensors can not be
greater than 0.1V, otherwise need to replace).
b), take down the sensor and measure the resistance, its resistance should be within standard deviation.
(6) Indoor fan failure
a), check whether capacitance of fan is the same with nominal value.or replace the capacitor or check
the next step.
b), for the tap fan,check voltage of high, medium and low wind relay.the normal voltage is DC12V.
c), for the tap fan,check whether the relay is normal.or may replace relay;
d), check whether the AC power supply circuit is normal, or replace related devices.
e), for the PG fan,check whether SCR (C1815) is cold solder joint, loose, this circuit is normal or not.
f), for the PG fan,check whether voltage of SCR (C1815) is normal (Point C is about 0.3V,Point b is
about 0.7V ,point e is 0V), or replace the C1815.
(7) step motor does not run or not good at running.
a), check whether solder joint of step motor is cold solder joint, loose and short-circuit for rosin, the
main chip, the output voltage of control pin is about 2V,or check whether the main chip is normal or
checking the next step;
b), check 4-pin voltage which connect the step motor with 2003 is normal(10 ~ 12V), or check the
2003 or the connecting wire.
C), check whether the connecting wire of step motor and the motor is normal.
(8) The relay does not work
a), check whether the voltage of the relay coil is normal (usually about 12V), otherwise check whether
the relays is normal or checking the next step;
b), check whether the relay is good, otherwise replace of relay;
c), check whether the output pin of the main chip is high (5V), or check whether the main chip is
normal or checking the next step.
d), check whether the power supply circuit, transformer input and output voltage is normal,or checking
the next step;
e), checking whether the piezoresistor and temperature insurance are normal.( the resistance of
piezoresistor is infinite.the resistance of temperature Insurance is 0) otherwise, check related