HCD-GT220, HCD-GT440, HCD-GT660, MHC-GT220, MHC-GT440, MHC-GT660 - Sony Audio Service Manual (repair manual). Page 18

This mode can run the CD sled motor freely. Use this mode, for instance, when cleaning the optical pick-up.
Procedure:
1.  Press the [

?/1

] button to turn the power on.

2.  Press the [CD] button to select “CD”.
3.  Press three buttons of [

x

], [FOLDER 

−] and [SURROUND] simultaneously, the message “SERVICE” is displayed on the fl uorescent 

indicator tube.

4.  Press the [TUNING 

−] button to move the optical pick-up to inside track and the message “SLED IN” is displayed on the fl uorescent 

indicator tude, or press the [TUNING +] button to outside track and the message “SLED OUT” is displayed on the fl uorescent indicator 
tube.

5.  Press the [DISPLAY] button, “LD ON” or “LD OFF” is displayed on the fl uorescent indicator tude. Each time [DISPLAY] button is 

pressed, laser diode on/off is changed over.

6.  To release this mode, press three buttons of [

x

], [FOLDER 

−] and [SURROUND].

This mode is used to check the fl uorescent indicator tube, LEDs, phones jack, keys and control knobs.
Procedure:
1.  Press the [

?/1

] button to turn the power on.

2.  Press three buttons of [

x

], [SURROUND] and [TUNER] simultaneously.

3.  All segments on the fl uorescent indicator tube and all LEDs light up.
4.  Press two buttons of [ILLUMINATUION] and [ENTER] simultaneously to enter the key routes check mode.
5.  In this mode, each time any button is pressed, it displays key route and key number of the button. (Refer to following table)

1

DISPLAY

ILLUMINATION

ENTER

DISC 1

+

2

POWER

ERASE

RETURN

DISC 2

ENTER(PEQ)

3

CD

PRESET EQ

FOLDER +

DISC 3

–

4

TUNER/BAND

GROOVE

TUNING +

DISC SKIP/
EX-CHANGE

GUITAR

5

TAPE A/B

SURROUND

PLAY/PAUSE

STOP

FOCUS (GUITAR)

6

AUDIO

EQ BAND 
(GT220/GT440) 
PLAY MODE/
TUNING MODE 
(GT660)

TUNING –

CD-USB SYNC/REC1

FOCUS (VOCAL)

7

USB

FOLDER –

CD-TAPE SYNC

VOCAL

8

SUBWOOFER 
(GT440/GT660)

OPEN/CLOSE

TAPE REC 
PAUSE/START

BASS

9

FOCUS (BASS)

Example: [DISPLAY] button 

: “KEY 10000”

 

[TUNER/BAND] button  : “KEY 40000”

 

[ILLUMINATION] button : “KEY 01000”

 

[CD-TAPE SYNC] button  : “KEY 00070”

6.  Press two buttons of [ILLUMINATUION] and [ENTER] simultaneously to enter the key check mode.
7.  In this mode, each time any button is pressed, “KEYCNT” value increases. However, once a button is pressed, it is no longer taken into 

account. (Maximum numbers are GT220: 29, GT440: 30, GT660: 39)

8.  Press two buttons of [ILLUMINATUION] and [ENTER] simultaneously to enter the phones jack check mode.
9.  In this mode, “H_P ON” is displayed when phones jack is inserted, and “H_P OFF” is displayed when phones jack is pulled out.
10. Press two buttons of [ILLUMINATUION] and [ENTER] simultaneously to enter the volume check mode and display “VOLUME 

FLAT”.

11. In this mode, “VOLUME UP” is displayed when [VOLUME] knob is turned clockwise, and “VOLUME DOWN” is displayed when 

[VOLUME] knob is turned counterclockwise.

12. Press two buttons of [ILLUMINATUION] and [ENTER] simultaneously to enter the jog check mode and display “JOG FLAT”.
13. In this mode, “JOG UP” is displayed when [OPERATION DIAL] knob is turned clockwise, and “JOG DOWN” is displayed when 

[OPERATION DIAL] knob is turned counterclockwise.

14. Press two buttons of [ILLUMINATUION] and [ENTER] simultaneously to release the Panel Test mode.