Sony MD Walkman MZ-E25, Service Manual

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5-4. IC PIN FUNCTION DESCRIPTION
•
MAIN BOARD IC501 SN761050A (RF AMPLIFIER)
Pin No. Pin Name I/O Function
1 to 4 IE, ID, IC, IF I Signal input from the optical pick-up detector
5 AGND —
Ground terminal (analog system)
6 VI I
I-V converted RF signal I input from the optical pick-up block detector
7 VJ I I-V converted RF signal J input from the optical pick-up block detector
8 AVCC —
Power supply terminal (+2.5V) (analog system)
9, 10 IB, IA I
Signal input from the optical pick-up detector
11 PD-IN + I Light amount monitor input terminal (non-invert input)
12 PD-IN – I
Light amount monitor input terminal (invert input)
13 PD-OUT O
Light amount monitor output terminal
14 LD-DRV O Laser amplifier output terminal to the automatic power control circuit
15 LD-SNS I
Laser drive current detector input terminal
16 LD-VDD I
Laser power supply voltage detector input terminal
17 DVA1 I Serial device code A1 (fixed at “L” in this set)
18 VTEMP O
Temperature sensor detection signal output to the system controller (IC801)
19 REXT1 —
Connected to external resistor for the temperature sensor control
20 DVDD —
Power supply terminal (+3V) (digital system)
21 SBUS I
Serial data input from the system controller (IC801)
22 SCK I
Serial data transfer clock signal input from the system controller (IC801)
23 DGND —
Ground terminal (digital system)
24 RESET I
System reset signal input from the MPC1830VMEL (IC901) “L”: reset
For several hundreds msec. after the power supply rises, “L” is input, then it changes to “H”
25 OFTRK O
Oftrack detection signal output to the D.S.P. (IC601)
26 DFCT O
Defect detection signal output to the D.S.P. (IC601)
27 EXT-IN I
External timing count signal input terminal Not used (open)
28 T-COUNT O
Timing count signal output to the D.S.P. (IC601)
29 ADIP O
ADIP duplex signal (22.05 kHz
±
1 kHz) output to the D.S.P. (IC601)
30 BPFC1 — Connected to the external capacitor for cutting the low band of the ADIP amplifier
31 BPFC0 —
Connected to the external capacitor for cutting the low band of the ADIP amplifier
32 REXT2 —
Connected to external resistor for the ADIP amplifier control
33 TE O Tracking error signal output to the D.S.P. (IC601)
34 OFTIN I
Oftrack detection signal input terminal
35 ABCD O
Light amount signal (ABCD) output to the D.S.P. (IC601)
36 FE O Focus error signal output to the D.S.P. (IC601)
37 RF-OUT O
Playback EFM RF signal output to the D.S.P. (IC601)
38 MIRR-VTH I
Threshold setting terminal for the mirror comparator
39 PS — Phase shifter for the RF amplifier
40 AGND —
Ground terminal (analog system)
41 EQ-2 —
Center frequency setting terminal for the internal circuit (RF EQ)
42 EQ-1 — Center frequency setting terminal for the internal circuit (RF EQ)
43 AVCC —
Power supply terminal (+2.5V) (analog system)
44 OFC-C1 —
Connected to the external capacitor for DC canceller
45 OFC-C2 —
Connected to the external capacitor for DC canceller
46 VREF2-OUT O
Reference voltage output terminal Not used (open)
47 VREF-OUT O
Reference voltage output terminal (+1.25V)
48 AGND —
Ground terminal (analog system)