I've been out of the consumer electronics service business for 15
years so this comment may be off base. Back then cheap cd spindle
motors would begin turning at 3 volts not 4. Have you blasted the
brushes with contact cleaner, spun the motor at a higher voltage for a
few minutes, and cleaned and lubricated the bearings? When Pioneer cd
player motors went bad, spinning the disc by hand would start them
playing. If this works, you'll know the motor is bad. Chuck


When Pioneers had a bad spindle motor, the disc still used to at least try
to turn, and it squealed like a stuck pig. Although other players tend not
to squeal like this, bad spindle motors are still common. On most players,
the disc will either rotate very slowly, or will rotate at a
'reasonable-looking' speed, but never actually reach a 'working' speed. It
is fairly rare for the motor not to start at all. The spindle motors will in
fact run at way less than 3 volts, as will the sled motors. The standard
test recommended by Pioneer was to connect the motor across an analogue
multi-meter set to its low ohms range. On this range, the impedance of the
meter was low enough that the internal 1.5 v battery could supply enough
current to run the motor. As well as running the motor, it also gave you an
indication of its 'resistance', which should be above 10 ohms. You could see
this figure climb from a few ohms when the motor was stationary, to over 10
ohms as the speed picked up, and back EMF started to contribute a term to
the meter reading.

You are quite right about squibbing switch cleaner in through the small
holes in the back-plate, and then 'blasting' the motor with excess voltage.
I do this with four or five short blasts of 12 volts first in one direction,
then the other. As you say, this is just a check though, and if the motor
runs and passes the 'meter' test afterward, it should still be replaced, as
it won't last long ...

Interesting that you used to employ this exact technique when you were in
the trade - presumably in the U.S. ? I first published it in a UK trade
magazine many years ago. Just goes to show that great minds think alike, for
you to have come up with it as well ! :-)

Arfa