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NOTE  FOR  REPLACEMENT  OF  THE  BT  BOARD
When repairing, the complete BT board (Part No. A-1641-142-A) 
should be replaced since any parts in the BT board cannot be re-
paired.

NOTE  FOR  REPLACEMENT  OF  THE  SERVO  BOARD
When repairing, the complete SERVO board (Part No. A-1554-
409-A) should be replaced since any parts in the SERVO board 
cannot be repaired.

NOTE  FOR  REPLACEMENT  OF  THE  USB  CONNECTOR 
(CN902)
To replace the USB connector requires alignment.
1.  Insert the USB connector into the front panel.
2.  Place the KEY board on the front panel and align the terminals 

of the USB connector with the holes in the KEY board.

3.  Solder the six terminals of the connector.

4-160-362-0[]

BT3800U: US and Canadian models

4-160-363-0[]

BT38UW

4-160-364-0[]

BT3800U: AEP and UK models

4-160-365-0[]

BT3807U

4-160-366-0[]

BT3850U:  E model

4-160-367-0[]

BT3850U: Saudi Arabia model

Notes on the lithium battery
• Keep the lithium battery out of the reach of children. 

• Wipe the battery with a dry cloth to assure a good 

• Be sure to observe the correct polarity when 

• Do not hold the battery with metallic tweezers, 

Under normal conditions, the battery will last approximately 1 year.
(The service life may be shorter, depending on the conditions of use.)
When the battery becomes weak, the range of the card remote commander
becomes shorter. 
Replace the battery with a new CR2025 lithium battery. Use of any other
battery may present a risk of fire or explosion.

1

2

c

WARNING
Battery may explode if mistreated.
Do not recharge, disassemble, or dispose of 
in fire.

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

that the conversation can be made.

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-BT38UW/BT3800U/BT3807U/BT3850U) 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 au-
dio device. (This function is disabled while the set is recon-
nected 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.

BLUETOOTH  FUNCTION  CHECKING  METHOD  USING  
A  CELLULAR  PHONE
1. Required Equipment
•  Set to be tested (MEX-BT38UW/BT3800U/BT3807U/

BT3850U)

•  Cellular phone (Recommended SEMC K320i or K800i, or 

select from connectable cellular phones list)

•  Speaker connection (at least Front L/R ch)
•  DC power supply (12V)

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)

3. Test Environment
•  No other Bluetooth device is making a communication in the 

periphery. (within 20m)

•  No other MEX-BT38UW/BT3800U/BT3807U/BT3850U are 

supplied with electric power.

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

periphery. (with 50m) (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-BT38UW/BT3800U/BT3807U/BT3850U 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-BT38UW/BT3800U/BT3807U/BT3850U.

•  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 5m to check if “XPLOD” is found.

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

phone (pass key 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 5m to check if the connec-
tion is held.

7.  After switching the source of the MEX-BT38UW/BT3800U/

BT3807U/BT3850U)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)

This section is extracted 
from instruction manual.

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