Service manual

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1 X-IN I
A crystal oscillator (4.5MHz) is connected between these pins.
22 X-OUT O
2 NC  Not connected.
3 CE I To enable the IC. Active "H".
4DII
Digital data input from CPU (LC87F65C8G-SAN1) when relevant key is operated.
Active "H".
5 CL I To clock in the data DI.
6 DO O Digital data output to CPU (LC87F65C8G-SAN1).
7 T-BASE O Outputs a reference clock signal (8Hz) for the clock.
8 MONO / BEAT O Outputs "H" when MONO / BEAT is switched.
Output "L" or "H" as follows:
9 FM / SW O
2 BAND 3 BAND 3 BAND
AM FM LW MW FM MW SW FM
HLHHLHLL
Outputs "L" or "H" as follows:
10 MW / SW O
2 BAND 3 BAND 3 BAND
AM FM LW MW FM MW SW FM
LLHLLLHL
11 IF-MUTE O To control internal counter.
12 IF-IN I General purpose counter input.
13 TUNE I Receives "L" when station is tuned.
14 NC  Not connected.
15 AM-IN I Receives the AM local oscillator frequency signal.
16 FM-IN I Receives the FM local oscillator frequency signal.
17 VDD  Supply power to IC (+5V).
18 PD O PLL charge pump output.
19 A-IN I
The MOS transistor used for PLL active low pass filter.
20 A-OUT O
21 VSS  Ground.
Pin No. Pin Name I/O Description
IC, LC72131D