"Mark D. Zacharias" wrote in
:

TJB wrote:
"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?

Thanks for the help so far
TJB

The motor can be checked with an ohmmeter at a low ohms range setting,
while SLOWLY rotating the motor. It should normally read 10 to 12 ohms
or so. The reading will vary while turning, but should not be
short-circuit or open at any one spot in it's rotation.

It is often possible to clear the short using an aerosol cleaner /
lubricant with a pinpoint applicator, sprayed through the slits at the
bottom, aimed at the brushes, while rotating manually, alternating
with blowing it out with a compressor. It's usually necessary to
repeat several times before the short clears. Blow out the excess
cleaner with the compressor. You really need to understand the
construction of small motors so you can "aim" the cleaner at the
brushes.

Mark Z.



Thanks, I will try the motor rotation test and see what happens.
Any thing else worth checking??

Thanks
TJB