Sam Goldwasser wrote in
:
"Mark D. Zacharias" writes:
TJB wrote:
TJB 2lazyToGet@one wrote in
:
Sam Goldwasser wrote in
:
TJB 2lazyToGet@one writes:
"Mark D. Zacharias" wrote in
t:
TJB wrote:
"N Cook" wrote in
:
TJB 2lazyToGet@one wrote in message
...
Need some help please, please, on a Yamaha CD Player model
cdc-60.
Just replaced the laser unit and it detects the CD and the
spindle motor starts up ok. Hit the play button and the unit
plays okay for about 15 minutes then starts to slow down,
speed generally wanders around and eventually stops and
indicates there is no CD present.
Is this likely to be a motor problem? If not any hints? This
unit is not the best to try and work on as you can't get to
anything while the it is playing
Thanks for any help
TJB
Try electrically disconnecting the motor (cut trace maybe)
and running it, the motor in isolation, from a bench power
supply to see if its a bearing problem.
Only low voltage, 1 to 2volts at most usually
--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list
on http://home.graffiti.net/diverse:graffiti.net/
I did try running the motor from a low voltage and it ran okay
but maybe I should let it run for 30min or so and see what
happens???
TJB
They had problems with shorted brushes on those motors...
Mark Z.
Is the problem I described above a symptom of shorted brushes. I
originally though it may be an overheating problem. Are there
any other faults which could manifest themselves as described?
Is it possible to clean/repair these motors or do you simply
just go and buy another one?
See: http://www.repairfaq.org/sam/cdfaq.htm#cdmot
--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Great repair faq!
Thanks
TJB
I measured the spindle motor resistance, it varied between 3 and 5
ohms. Normal??? Doesn't seem to have any slop in the bearing, but
I put a very small drop of machine oil on it anyway.
I also noticed another possible problem with this deck: the
clearance from the bottom of a cd in the holder to a plastic
locating pin which pushes through a slot in the turntable is very
very small. Possibly the spindle platter height is to low? There is
a remote chance of a cd rubbing on this pin as it is playing.
Anyone have a value from the correct platter height? I measured
from the chassis to the very start of the black plastic platter at
8.3mm, oops I probably should have measured to the flange where a
cd would sit.
Anyway can anyone let me know what the platter height measurement
should be : I guess that would be from where a cd sits to the
chassis??
Thanks
TJB
I'm almost certain the 3 to 5 ohms is too low. Spindle height is not
standarized from model to model, but I believe it needs to be about 2
to 3 mm clearance from the pickup lens to the underside of the disc.
Mark Z.
I agree that 3 to 5 ohms sounds low. Try this quick test: Disconnect
the motor from the CD player and run it for a few seconds *only* at
8 or 10 V. This may blow out some of the crud but shouldn't damage
an otherwise healthy motor. Then retest and report back. 
--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html
Important: Anything sent to the email address in the message header
above is ignored unless my full name AND either lasers or electronics
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Feedback Form in the FAQs.
Pickup lense seems to be around 2mm, its that damn turntable locating
pin (don't know why is has to be sooo big) that seems to close for
comfort.
Tried it for a few secs at a higher voltage; the motor still measures
around 3-5 ohms turning it slowly by hand. maybe I should just change
it. Seems simple enough the platter is just a tight fit and should just
pull straight off.
Thanks
TJB