ICD-P28 - Sony Audio Service Manual (repair manual). Page 10

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9. USB test
• When the menu starts the USB self-check, either presence or

absence of the Vbus is judged.
(Vbus is present: “VBUS: ON”, Vbus is absent: “VBUS: OFF”)

• The USB driver always works regardless of presence or absence

of the USB signal only when Vbus is available during the USB
test. At this time, turning on  HOLD  causes the set to move to
the suspend state. Turning off the Vbus causes the set to return
to the test menu.
When Vbus is supplied with the menu displayed, the key will be
inoperative. Be sure to press  x•B  key before supplying.

10. Key durability test
• Input of  x•B  key causes the counter to be “- - - - - -”, entering

the test waiting mode. Input of  x•B  key causes the counter to
be “000000”, entering the key durability test mode.
In this mode, all key inputs and ON and OFF operations of the
slide switch are counted with a count display. Turn the power
off in order to exit this mode.

11. Menu reset
• Pressing the  x•B    key causes the set to enter the menu

initialization standby state.

• Once all the keys below are input in this condition, the EEPROM

will be initialized (The settings in the menu and the user name
will be defaulted.).
At the same time, the WakeUp signal is checked, too.

• Check keys (in any order of their inputs)

FOLDER  ,  DIVIDE  ,  DISPLAY  ,  MENU  ,  MIC SENS  ,
ERASE  ,  STOP  ,  REC/STOP  ,  PAUSE  ,
PLAY/STOP (ENTER)  ,  >  ,  .  ,  HOLD  on,
HOLD  off

(All is normally ended: –ALLOK–/NG in initialization write
to EEPROM: INIT. NG)

• Turn the power off in order to exit this mode.

x 

• B

STOP

HOLD  ON

USB

VBUS

VBUS on

Suspend mode

Cut VBUS

Cut VBUS

OFF

VBUS

ON

LINK

PC

x 

• B

STOP

COUNT

KEY

- - - - - -  

KEY

x 

• B

00  00  00

KEY

KEY

Key endurance
test mode

any keys or
slid switchs on/off

00  00  01

x 

• B

STOP

PUSH

After input all keys

Case of initial setting
and reset operated
normal end.

KEY

MENU

RST

INIT (Blink)

ALL

Ok