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Note on Schematic Diagram:
• All capacitors are in µF unless otherwise noted. pF: µµF
50 WV or less are not indicated except for electrolytics
and tantalums.
• All resistors are in Ω and
1
/
specified.
•
: internal component.
f
• C : panel designation.
• A : B+ Line.
• H : adjustment for repair.
• Power voltage is dc 1.5 V and fed with regulated dc power
supply from battery terminal.
• Voltages and waveforms are dc with respect to ground
under no-signal (detuned) conditions.
Main board (1/3)
no mark : FM/AM, TAPE STOP
(
) : FM
[
] : AM
<
> : TAPE PB
Main board (2/3), (3/3)
no mark : REC / PB
(
) : REC
[
] : PB
• Voltages are taken with a VOM (Input impedance 10 MΩ).
Voltage variations may be noted due to normal produc-
tion tolerances.
• Waveforms are taken with a oscilloscope.
Voltage variations may be noted due to normal produc-
tion tolerances.
• Circled numbers refer to waveforms.
• Signal path.
E
: PB
a
: REC
F
: FM
Note on Printed Wiring Board:
• Y : parts extracted from the conductor side.
• b : Pattern from the side which enables seeing.
Caution:
Pattern face side:
Parts on the pattern face side seen from
(Side A)
the pattern face are indicated.
Parts face side:
Parts on the parts face side seen from
(Side B)
the parts face are indicated.
W or less unless otherwise
4
• Waveform
1
20µsec/div
TP32
2
IC2 !¶ VCO 5µsec/div
3
IC801 5 PLAY BACK mode
4
IC3 &¢ XOUT 5µsec/div
— 15 —
WM-GX680/GX688
5V/div
51.7kHz
50mV/div
5µsec/div
1V/div
0.5V/div
75kHz
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