MEX-BT4700U, MEX-BT4750U - Sony Car Audio Service Manual (repair manual). Page 5

10.  Check that the other party’s voice can be heard from the speak-

er.

11. Check by operating the Volume that the other party’s volume 

varies.

12.  Speak to the microphone of the set to check that the other party 

can hear it. (Make sure that there is no large difference from 
normal set)

13. Press the [PUSH SELECT] button for 2 seconds to check that 

the HF turns off and the set is switched to a telephone call 
between cellular phones. (This may not function depending on 
the cellular phone)

14. Press the [PUSH SELECT] button for 2 seconds to check that 

the HF turns on and the set is switched to a telephone call be-
tween MEX-BT4700U/BT4750U and far end.

15. Press the [PUSH SELECT] button for a short time to check 

that a telephone call is terminated. Also, the original source is 
returned.

16. Perform ACC OFF 

→ ON to check if the set is reconnected 

automatically to the cellular phone.

7.  BT Audio Function Check
1.  Connect the set to the BT audio device (or cellular phone fur-

nished with BT audio function) to check that the streaming 
logo lights up.

2.  Play the BT audio device to check that a sound is generated 

from the set when the source is switched to the BT audio.

3.  Operate the set ([SEEK – /+], [6] button operation) to check if 

it can control the BT Audio.

Note: The functions that can be operated vary depending on the BT audio 

device connected.

4. Perform 

ACC 

OFF 

→ ON to check if the set can be recon-

nected to the BT audio device. (Some BT audio devices may 
be reconnected automatically)

5.  With the BT audio source, press the [6] button to check if the 

streaming logo blinks and the set is reconnected to the BT audio 
device. (This function is disabled while the set is reconnected 
to a cellular phone. Accordingly, this test should be conducted 
after the power is turned on and then the HF logo lights up, or 
when about 30 seconds elapsed after the power on)

8. Initialize
This should be performed when the set is sent back to the user after 
all the checks fi nished successfully.
1.  Execute the initialization.
2.  Press the [BLUETOOTH] button for 3 seconds to check if the 

BT logo lights up.

3.  Check that the set is not connected automatically to the cellular 

phone that was connected last.

4.  With the BT audio source, check that the streaming logo does 

not blink when the [6] button is pressed.

9.  What to Do after Checking
1.  If the board does not need to be replaced
• 

Return the bluetooth settings to original ones. (settings when 
the set was received from the user)

2.  If the board needs to be replaced
• 

Return to the factory shipping mode.

• 

Set to be tested (MEX-BT4700U/BT4750U)

• 

Cellular phone (Recommended SEMC K320i or K800i, or se-
lect from connectable cellular phones list)

• 

Speaker connection (at least Front L/R ch)

• 

DC power supply (12 V)

2. Preparation
Turn on the Bluetooth function of the cellular phone in advance.
Remove a Bluetooth device connected to the cellular phone in ad-
vance. (at least, remove XPLOD)

• 

No other Bluetooth device is making a communication in the 
periphery. (within 20 m)

• 

No other MEX-BT4700U/BT4750U are supplied with electric 
power.

•  There are no two or more wireless LAN access points in the 

periphery. (with 50 m) (one is OK)

• 

The set should be tested in a place such as a meeting room, free 
from ambient noise.

• 

The speaker at the far end should be in a place such as another 
meeting room separated acoustically.

4. Setting
Install the MEX-BT4700U/BT4750U on the desktop.

5. Precautions
Beware of the following points when conducting the 
talking test:
• 

There is no fault if a talking can be made by adjusting appro-
priately the volume of the telephone of the other party and the 
cellular phone connected through the Bluetooth, besides the 
setup of MEX-BT4700U/BT4750U.

• 

The speaker’s voice will become loud naturally if the periph-
ery is noisy, or become low if quiet. (even though the speaker 
intents to talk on the same volume level)

•  The speaker’s voice will become loud naturally if the other 

party’s voice is loud.

6.  BT PHONE Function Check
1.  Press the [BLUETOOTH] button for 5 seconds to check if the 

BT logo changes from lighting to blinking.

2.  Search peripheral equipment from the cellular phone to check 

if “XPLOD” is found.

3.  Search peripheral equipment from the cellular phone apart 

from the set about 5 m to check if “XPLOD” is found.

4.  Check if peripheral equipment can be registered to the cellular 

phone (pass code 0000).

5.  Make a connection to the cellular phone to check if the HF 

logo lights up. (This may be conducted at the same time in item 
4)

6.  After making a connection to the cellular phone, move the cel-

lular phone apart from the set about 5 m to check if the connec-
tion is held.

7.  After switching the source of the MEX-BT4700U/BT4750U 

to other than BT PHONE (e.g. TUNER) to check that a sound 
is generated, make a call to the cellular phone connected to the 
set.

8.  Check that the sound being played is interrupted and in turn the 

ring tone is heard. (the built-in sound of the set will be gener-
ated or the ring tone of cellular phone will be heard depending 
on the cellular phone)

9.  Press the [PUSH SELECT] button for a short time to check 

that the conversation can be made.