portable dvd player audiosonic. fault . spindle motor not turning. model KM0502

hi , i have a audiosonic portable dvd player , model KM0502.

the problem with it is , is that when u insert a dvd disc ,it doesnt
turn, the laser moves ok, and it says " disc not inserted "
i then connected a 1.5 volt battery to the motor , and it turned ok.

so i presume the power supply section on teh pc board is damaged.

would it be possible to make up a simple reg supply just for the motor ?
the thing is , i dont have a clue as to what voltage the motor is ?

anybody know ?

thanks,
mark k

 

I'm afraid your diagnostic logic is way off beam here. The fact that the
disc does not spin up, is not a sign that either the motor, or its drive /
power supply circuitry is faulty. Most likely, the laser is not obtaining
focus, so the spindle motor servo is not being turned on by the system
control micro. First ensure that the sled drive is working correctly by
manually moving the laser out towards the disc edge, then reclosing the
door. Open it again, and ensure that the laser has 'homed' back to the disc
centre. If this checks out ok, try a CD in the player, rather than a DVD. If
a CD plays, but not a DVD, suspect a defective laser ( although not
always ). If neither type of disc plays, then you likely have a digital
processor / decoder problem. Either of these problems probably render the
unit landfill, unfortunately ...

Arfa

 

So the laser focuses before the disc spins up?

 

In most cases, yes. Sometimes, if focus cannot be obtained on the first try
sequence, the spindle servo will pulse the motor a little, to rotate the
disc a few degrees, before trying again, in case it was trying to read
through a jammy fingerprint. Some players just go ahead and spin up the disc
and look for a focus lock, followed by any old data coming off the disc,
that they can then get spindle and tracking servo locks on, but by and
large, the sequence is :- check optical block is home, if yes, turn on laser
and initiate focus search. When focus lock obtained, turn on spindle and
tracking servos. Read data and use to fine tune servos. Read and display
disc menu or TOC.

Arfa

 

Thanks for the explanation. Way back when I was working on this kind of
stuff if I recall correctly, the disc always spun up first. Since consumer
CD players were in their infancy back then in the early 80's, maybe the
logic control was limited in how the laser accomplished a disc check.
Also this could be a way to save a bit of power on portables by not
wasting it to spin an empty motor?

 

Maybe, but I just fixed a Toshiba home player today the wouldn't spin
up, and rejected the disk. If I loaded the disk and spun it manually,
it would pulse a few times, the sled would track and then it would reject.

Turned out to simply be a dirty lens. Aside: Lacking alcohol, which I
normally use....simply moistened a cotton swab with plain water, and it
did the trick (dried it off, of course).

I remember the first time I encountered this problem...on a Technics CD
changer. I farted around with the spindle motor and associated
circuitry for hours before doing a simple lens cleaning. That's all it
needed. That was maybe ten years ago, and the unit was used when I
bought it...perhaps 1992 vintage.

Always clean the lens first! It can't hurt; and (most?) often is the
entire fix.

jak