Samsung RB195BSSB Service Manual - Page 47

Source Power Circuit, 2 Oscillation Circuit

Page 47 highlights

OPERATION PRINCIPLES BY PARTS OF CIRCUIT 12-1) SOURCE POWER CIRCUIT Power Vcc(DC 5V) +12V(DC 12V) Circuit MICOM POWER AND SENSORS RELAY,PANEL DRIVING CIRCUIT 1) When the power is supplied,AC voltage stepped down on the 2nd transformer flows between ①and ③at about AC 16V and changes to DC voltage when it goes through the diode D101 and D108,and constant 12V will be output via regulator REG1(7812).And,it will supply DC5V to MICOM and power to other circuits via regulator REG2 (MC7805ACT),and make entire PCB operate. 12-2) OSCILLATION CIRCUIT Terminal Xin(#19) Xout(#18) Oscillation Freq. 8MHz 8MHz 1) It is an Oscillation Circuit for synchronism clock generation and time calculation on the information sending &receiving of the MICOM internal logic elements and when specifications for Resonator change,the timing system of MICOM changes resulting in errors. (Rated parts must be used) 47

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47
OPERATION PRINCIPLES BY PARTS OF CIRCUIT
Power
Vcc(DC 5V)
+12V(DC 12V)
Circuit
MICOM POWER AND SENSORS
RELAY,PANEL DRIVING CIRCUIT
1) When the power is supplied,AC voltage stepped down on the 2nd transformer flows between
and
at about AC 16V and changes to DC voltage when it goes through the diode D101 and D108,and
constant 12V will be output via regulator REG1(7812).And,it will supply DC5V to MICOM and power
to other circuits via regulator REG2 (MC7805ACT),and make entire PCB operate.
1) It is an Oscillation Circuit for synchronism clock generation and time calculation on the information
sending &receiving of the MICOM internal logic elements and when specifications for Resonator
change,the timing system of MICOM changes resulting in errors. (Rated parts must be used)
Terminal
Xin(#19)
Xout(#18)
Oscillation Freq.
8MHz
8MHz
12-1) SOURCE POWER CIRCUIT
12-2) OSCILLATION CIRCUIT