Wednesday, May 16, 2012

"NO DISC' DISPLAY TO DISC PLAYERS - 3


Cont:-
     An other reason for NO DISC display is with its main board.  The common fault I came across is with defective motor drive IC.  There are mainly three motors with most disc players.  One is for in-out tray dirve, one for laser pickup unit movement, and the other for spinning the disc.  Out of these, motors that drives to spin disc and to move laser pickup unit are controlled by a single IC.  This IC is soldered directly to main board of the player, in most models.  This IC will heat up to an extent.  This IC is SMD [Surface Mount Device] type.  Can be replaced by an expereinced service technician.  You can make sure about its fault, by touch it by bare finger while it works.  If feel over heat, and either the disc spin motor or trcking motor do not rotate, switch OFF the set.  Pull out the supply wires goes to mechanism.  Switch ON the set in this condition.  Feel the heat of the IC.  It should be cool.  If it heats up, and the temperature rises even without connecting the wires to the motors, make sure that this IC is damaged.  This is the only IC, wich can be repalced by hand soldering. 

     If the IC do not heat after disconnecting the connection wires to mechanism, there is some short inside either one motor [sled motor or tracking motor]. 

     It is best to replace both this motors at the same time, rather than making more tests by connecting it to drive IC.  These motors are stepper motors, can be bought from most of the electronic spare part selling shops at your town, and won't cost more.  It will have a number printed on it ans should be noted before buying a new one.

No comments: