MEX-BT3800U, MEX-BT3807U, MEX-BT3850U, MEX-BT38UW - Sony Car Audio Service Manual (repair manual). Page 5

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.