MEX-BT2800, MEX-BT2807E, MEX-BT2850 - 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-1433-972-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-1552-
122-A) should be replaced since any parts in the SERVO board 
cannot be repaired.

NOTE  FOR  REPLACEMENT  OF  THE  AUX  JACK 
(J901)
To replace the AUX jack requires alignment.
1.  Insert the AUX jack into the front panel.
2.  Place the KEY board on the front panel and align the terminals 

of the AUX jack with the holes in the KEY board.

3.  Solder the three terminals of the jack.

4-157-843-0[]

BT2800: US and Canadian models

4-157-844-0[]

BT2800: AEP and UK models

4-157-845-0[]

BT2807E

4-157-846-0[]

BT2850: E model

4-157-847-0[]

BT2850: Saudi Arabia model

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.

Notes on the lithium battery
s Keep the lithium battery out of the reach of children. Should the battery be 

s Wipe the battery with a dry cloth to assure a good contact.
s Be sure to observe the correct polarity when installing the battery.
s Do not hold the battery with metallic tweezers, otherwise a short-circuit 

1

2

c

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