Table of Contents
Advertisement
5.18
Repair tips, English
Repair tips
Voltage to sledge motor
Repair of autopositioning
Why does the product not work?
CD
Disconnect the voltage supply to the sledge motor while servicing (lift 35P53).
TM73 is used in connection with repair of autopositioning. The circuit can be
measured each time the test is run. Use a storage oscilloscope, if necessary.
Only the signals SWAB and SDAB can be measured during lead-in, i.e. during
ordinary play-back of a CD.
Autopositioning errors of less than 5 degrees may occur in rare cases.
If the product does not work, the reason may be one of the following:
When the glass lid is not installed the sledge may stop during movement. That is
because the IR beam in the fi nger protection system transmits at reduced power
when the lid is closed. Run the lid hinges to the open position for maximum IR
transmitter power (see test mode 74, if required).
A lid acknowledgment must be given for the product to operate. The lid may be
subject to an adjustment error so than no acknowledgment is received.
If the fi nger protection beam is broken, the sledge cannot move.
If end stops have not been detected, the product will not operate.
If the optocouplers is the product are affected by external light the product will
not operate.
In connection with repair of the CD the following tips may be useful:
THE PHOTO DIODES AND THE LASER ARE MORE SENSITIVE TO STATIC ELECTRICITY
THAN THE MOS IC'S. OMISSION TO TAKE THIS INTO CONSIDERATION DURING
SERVICING MAY REDUCE THEIR LIVES DRAMATICALLY. SO BE SURE THAT THE
WORK SITE IS PROTECTED AGAINST STATIC ELECTRICITY.
The product may not be connected to the mains while the CD mechanism or
PCB41 are removed.
Focus can be checked by placing a CD over the light pen. The light pen will now
"follow" the CD (up/down).
In normal operation the CD will fi rst search for Focus, and when that has been
found it will start the turntable motor, i.e. if the motor cannot start, the reason
may be that focus has not been found.
The CD can run without clamper and disc detector. In test mode select CD as
source. Move the sledge to position 1, disconnect the voltage supply to the sledge
motor while servicing the CD (lift 35P53), load a CD, press CD, and the CD can
now be played back.
Advertisement
Table of Contents
