Panasonic KX-TDA100BX, Service Manual

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clock block power.
BAT401, which is a lithium battery for memory backup, is connected to the power supply of IC301, IC302 (SRAM) via D408,
D409.
IC411 compares BAT401 output voltage to the reference voltage (about 2.8V) and drives LED (BATALM) that indicates
dropping of backup voltage.
IP401 and IP402 block the line respectively when over current flows to +15V and +3.3V line.
10 BACK BOARD CIRCUIT OPERATION
The back board (BB) connects signals between all cards in main unit. It also supplies power from the power supply unit (PSU)
to the cards.
CONNECTORS EXPLANATION
(1) Power Supply Unit Connector: CN100
(2) Free Slot Connectors: CN103-CN106
(3) Option Card Slot Connector: CN107
(4) MPR Card Connector: CN112
(5) RS-232C Connector: CN113
CN113 is connected to D-Sub connector in front of the product.
(6) LED Connector: CN114
CN114 is connected to LED Board on the product.
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KX-TDA100BX