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6. CIRCUIT EXPLANATION
6-1. Power supply circuit
Q1 :
Transistor for controlling voltage (VP)
Q2 :
Transistor for voltage detection
Q3 :
Transistor for controlling power down (PWD) signal
ZD2 :
Zener diode for controlling base current of Q2
ZD3 :
Zener diode for detecting power down (PWD) signal
After plug the AC cord into the outlet, the AC voltage (23.8V) appears at CN1 connector.
Then this voltage is rectified by the diode brige and it become constant voltage through the capacitor C1.
[Voltage VP]
A constant voltage (31.4V) appears on the “ 2 “ position. This voltage made from the constant
voltage circuit consist of transistor Q1 and Q2, zener diode ZD2, resisror R7, R8, R12 and R13.
[Voltage VLED and VCC]
The voltage goes to pin No.1 of regurator IC1 and then it is out from pin No.2 of IC1 as stable
voltage (5.6V).
Then this voltage down to 5 volts through the diode.
It is used for VCC ( for logic) and VLED (for display drive).
Also, it goes to pin No.4 of IC1 and using to control the output voltage level.
Inductor L1 is used to stabilize the VCC voltage when the drawer opened.
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Summary of Contents for CE-235
Page 1: ...SERVICE MANUAL ELECTRONIC CASH REGISTER CE 2350 EX 259 JAN 1995...
Page 18: ...8 PCB LAYOUT 16...
Page 19: ...17...
Page 20: ...18...
Page 21: ...19...
Page 22: ...20...
Page 23: ...21...
Page 24: ...22...
Page 25: ...23...
Page 26: ...24...
Page 27: ...25...
Page 28: ...26...
Page 29: ...27...
Page 36: ...34 5 Button block 33 26 32 27 35 34 31 29 36 37 28 25 24 44 40 40 2 42 42 41 23 39 38 30 43 22...
Page 39: ...37 7 Upper case block 55 56 54 52 51 50 57 58 53 49...
Page 42: ...40 9 Printer unit...
Page 44: ...42 10 Drawer unit 10 1 DL 2417 for U S A...
Page 46: ...44 10 2 DL 2351 for Canada...