Service Note - Sony Walkman WM-GX670 Service Manual

[Service Mode]
The service mode enables to operate the mechanism of WM-GX670/
GX674 while the MAIN board is opened.
Rotation of the idler gear (A) (S side) is detected using the photo-
reflector (PH1) in the WM-GX670/GX674. PH1 is located on the
MAIN board, therefore the rotation of the idler gear (A) (S side)
cannot be detected by PH1 when the MAIN board is removed. As
a result, the motor cannot be controlled and cannot run correctly.
To repair the machine after the MAIN board is removed while the
main power is turned on, follow the procedures as described below.
1. Setting
1) Remove the cabinets referring to section "3. DISASSEMBLY".
Open the MAIN board.
2) Connect the motor (M601) and the plunger solenoid (PM901)
to the MAIN board using the jumper wires. When the extension
jig (1-769-143-11) (10 wires as a set) is used, they can be
connected easily.
3) Short the TAPE DETECT switch (S901-2), R TUME switch
(S901-1), F TUME switch (S902-1) and ATS switch (S902-2).
4) Connect an AF oscillator to resistor (R43).
Connect DC 1.3 V from external regulated power supply to '
5)
and ' terminals of the battery.
2. PRE-SET status
The PLAY, FF and REW modes can be entered only from the PRE-
SET status.
1) Check that the slider (NR) is in the center position (S1), and
the FWD/REV switch is also in the center position. When
these switches are not in the center position, set them to the
PRE-SET status as follows.
2) Move the FWD/REV switch (S1) to the same position as the
slider (NR) is set.
3) The slider (NR) can be moved when the main power of the
regulated power supply is turned OFF once then back ON.
Move the FWD/REV switch (S1) to the center position in
synchronism with the timing when the slider (NR) is moved.
R TUME TAPE DETECT
SWITCH SWITCH
(S901-1) (S901-2)
Short
REW AMS
(S5)
REC
(S11)
SECTION 1
SERVISE NOTE
– MAIN BOARD (SIDE B) —
Plunger (PM901)
Battery terminal '
FF AMS
(S4)
œ REPEAT
(S9)
p
(S3)
ENTER
(S10)
3. FF, REW modes
1) Check that the PRE-SET status is set.
2) Connect square wave or sine wave to resistor (R43). (See
illustration below.)
Press the p switch (S3) to enter the STOP mode.
3)
4) Press the FF AMS switch (S4) and the REW AMS switch
(S5).
4. PLAY mode
1) Check that the PRE-SET status is set.
2) Connect square wave or sine wave to resistor (R43). (See
illustration below.)
Press the p switch (S3) to enter the stop mode.
3)
When the 9(REPEAT switch (S9) of the MAIN board is
4)
pressed, the slider (N/R) moves once to the F side then moves
to the R side. When the FWD/REV switch (S1) is pressed in
the synchronism with the above timing, the machine can enter
the PLAY (R side) mode. Press the 9(REPEAT switch
(S9) again, and move the FWD/REV switch (S1) in the
synchronism with the motion of slider (NR). It enables the
machine to enter into the PLAY (F side) mode.
Note 1: When you fail to enter the PLAY mode, re-start from step
1) PRE-SET status.
Note 2: Regarding the 9(REPEAT (S9), p (S3),
FF AMS (S4), and REW AMS (S5) switches, use these
switches of the remote control unit as much as possible.
Note 3: If a headphones are used, the beep sound shows the timing
of the FWD/REV switch (S1).
AF OSC
Square-wave
(sine wave)
10 Hz, -3.5 dB
Q15
R43
(SIDE A)
(SIDE A)
MENU
(S6)
BAND
(S1)
(S8)
FWD STOP REV
— 3 —
ATS F TUME
SWITCH SWITCH
(S902-2) (S902-1)
Battery terminal '
Short
SET
M
M601
(S7)