8. CIRCUIT OPERATION (HANDSET)
8.1. MAIN BOARD
8.1.1. POWER SUPPLY CIRCUIT
The power supply circuit consists of 4 regulators. IC314 supplies the power to the CPU(IC307).
IC301, IC305 and IC308 are controlled by the CPU(IC307). Each output voltage is 3.0V.
8.1.2. RINGER CIRCUIT
When the Ring signal is received with the power switch of the handset ON, the ringer is
activated. When the ring signal is received, IC307(45) and IC307(46) are, set High or Low.
(Depends on Ringer Vol setting) After Q302 and Q305 are set High or Low, Q304 and Q300 are
switched on by the ringer frequency in IC307(45) (Q300 is a High Current Driver) and the buzzer
is then ON.
8.1.3. RECEIVED VOICE SIGNAL
Summary of Contents for KX-TD7895 - Digital Spread Spedtrum Telephone
Page 3: ...3 2 CONNECTIONS OF HANDSET ...
Page 4: ...3 3 BASE UNIT ...
Page 5: ...4 DISASSEMBLY INSTRUCTIONS 4 1 BASE UNIT ...
Page 6: ...1 Remove the four screws A and remove the Bottom Cabinet ...
Page 9: ...2 Take the Battery out of the Rear Cabinet after disconnecting the Connector ...
Page 10: ...3 Remove two Screws D from the Rear Cabinet ...
Page 12: ...6 Remove the Antenna from the Front Cabinet after removing the Screw E ...
Page 13: ...7 Remove the RF unit from the Main Board ...
Page 20: ...34 CHARGE I ON OFF ...
Page 23: ...6 4 RF UNIT FREQUENCY TABLE ...
Page 32: ...10 TROUBLESHOOTING GUIDE 10 1 NO VOICE RECEPTION 10 2 NO VOICE TRANSMISSION ...
Page 33: ...10 3 NO LINK BASE UNIT ...
Page 39: ...12 CABINET AND ELECTRICAL PARTS LOCATION 12 1 BASE UNIT ...
Page 40: ...12 2 HANDSET ...
Page 41: ...12 3 CHARGER ...
Page 42: ...13 ACCESSORIES AND PACKING MATERIALS ...
Page 46: ... CAPACITORS ...
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Page 64: ......