CMT-DX400, CMT-DX400A, HCD-DX400 - Sony Audio Service Manual (repair manual). Page 3

UNLEADED  SOLDER
Boards requiring use of unleaded solder are printed with the lead-
free mark (LF) indicating the solder contains no lead.
(Caution:  Some printed circuit boards may not come printed with 

the lead free mark due to their particular size)

Unleaded solder has the following characteristics.
•  Unleaded solder melts at a temperature about 40 °C higher 

than ordinary solder.

 

Ordinary soldering irons can be used but the iron tip has to be 
applied to the solder joint for a slightly longer time.

 

Soldering irons using a temperature regulator should be set to 
about 350 °C.
Caution: The printed pattern (copper foil) may peel away if 

the heated tip is applied for too long, so be careful!

• Strong 

viscosity

 

Unleaded solder is more viscous (sticky, less prone to fl ow) 
than ordinary solder so use caution not to let solder bridges 
occur such as on IC pins, etc.

•  Usable with ordinary solder
 

It is best to use only unleaded solder but unleaded solder may 
also be added to ordinary solder.

The laser diode in the optical pick-up block may suffer electro-
static break-down because of the potential difference generated by 
the charged electrostatic load, etc. on clothing and the human body.
During repair, pay attention to electrostatic break-down and also 
use the procedure in the printed matter which is included in the 
repair parts.
The fl exible board is easily damaged and should be handled with 
care.

NOTE  THE  EACH  BOARDS  REPAIRING
The mount parts on each boards installed in this set cannot ex-
change with single. When the each mount parts are damaged, ex-
change the entire mounted board.
Printed wiring board and schematic diagram have been described 
to this service manual is for the reference. 

NOTES  ON  LASER  DIODE  EMISSION  CHECK
The laser beam on this model is concentrated so as to be focused 
on the disc refl ective surface by the objective lens in the optical 
pickup block. Therefore, when checking the laser diode emission, 
observe from more than 30 cm away from the objective lens.

TRAY  LOCK/UNLOCK  MODE
Procedure:
1.  Press the [

?/1

] button to turn on the system.

2.  Press and hold the [

x

] and [OPEN/CLOSE 

Z

] buttons (around 

5 seconds).

3.  The message “LOCKED” appears on the fl uorescent indicator 

tube, and disc tray is locked.

4.  To release this mode, do the step 2 again.
5.  The message “UNLOCKED” is displayed on the fl uorescent 

indicator tube, and the disc tray is unlocked.