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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

Spins too fast! Alpine CD changer



 
 
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  #1  
Old December 22nd 04, 09:11 PM
boredwild
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Default Spins too fast! Alpine CD changer

Model CHM-S601. At first, chager loaded each disc in succession, would
not spin up, and proceeded to next disk. Opened it up to check laser
operation. Pickup bobs up and down and light comes on for each disc.
Gave the disc a spin and it spun up really fast, then the changer tried
to change discs while it was spinning at high speed. Now each disc
will spin (but at high speed) for 20 s or so and then proceed to the
next. Any suggestions? Thanks.

Jeff

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  #2  
Old December 22nd 04, 09:54 PM
jakdedert
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boredwild wrote:
Model CHM-S601. At first, chager loaded each disc in succession,
would not spin up, and proceeded to next disk. Opened it up to check
laser operation. Pickup bobs up and down and light comes on for each
disc. Gave the disc a spin and it spun up really fast, then the
changer tried to change discs while it was spinning at high speed.
Now each disc will spin (but at high speed) for 20 s or so and then
proceed to the next. Any suggestions? Thanks.

Jeff


Clean the lens. The unit is not recognizing the disc. Hopefully that will
fix it. If not, your problem could be deeper; but the speed is IMO not the
problem.

jak


  #3  
Old December 22nd 04, 09:55 PM
Jerry G.
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Check to see if the laser lens requires to be cleaned. If the laser it
cleaned, it is possible that the laser unit is becoming weak, or the
electronics that drives it, or reads it is going weak. In this case if
the laser is clean, proper verification of the circuits involved would
be the next step to take.

To service these players, you will need the proper test setup, the
service manual, and a discent understanding of the machine's operation
at the technical level.

Another easy suggestion is to see that the spindle motor can turn
easily, and that the laser assembly can move easily along its tracks.

If this is an expensive player, I would suggest you take it in for an
estimate, or otherwise, it may be better worth to replace.

Jerry G.
========


boredwild wrote:
Model CHM-S601. At first, chager loaded each disc in succession,

would
not spin up, and proceeded to next disk. Opened it up to check laser
operation. Pickup bobs up and down and light comes on for each disc.
Gave the disc a spin and it spun up really fast, then the changer

tried
to change discs while it was spinning at high speed. Now each disc
will spin (but at high speed) for 20 s or so and then proceed to the
next. Any suggestions? Thanks.

Jeff


  #4  
Old December 23rd 04, 01:24 AM
boredwild
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Thanks, guys. Forgot to mention that I cleaned the laser with 99%
ethyl (to no avail).

  #5  
Old December 23rd 04, 08:03 AM
boredwild
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Gave the potentiometer on the laser pickup a tweak (counterclockwise),
and away she went! Glad I didn't have to buy anything or take it to a
shop.

  #6  
Old December 23rd 04, 11:07 AM
ChipMIK
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boredwild wrote:
Gave the potentiometer on the laser pickup a tweak (counterclockwise),
and away she went! Glad I didn't have to buy anything or take it to a
shop.

Hi

BE CAREFUL....hope you measured it before you tweaked it....you should
not go below 90% of whatever it was, or it might VERY quickly become a
dead laser !....did you try clean the lens first...many time this is
where the real prob is...tweaking laserpot cures the prob
initially...but it might be only for a short time

Good luck

ChipMIK..PS2 chipinstaller.diesel box tuner..well heck ill tune anything
  #7  
Old December 23rd 04, 11:32 AM
boredwild
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Thanks for the warning. Would it seem that the problem is the laser
itself (in which case I would have nothing to lose by adjusting it) or
could it be with another component, and is simply masked by adjusting
the laserpot?

  #8  
Old December 23rd 04, 06:30 PM
James Sweet
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"boredwild" wrote in message
oups.com...
Thanks for the warning. Would it seem that the problem is the laser
itself (in which case I would have nothing to lose by adjusting it) or
could it be with another component, and is simply masked by adjusting
the laserpot?


The lasers do go weak with age, if you've already cleaned the optics to the
best of your ability you have nothing to lose by tweaking the laser, just
don't tweak it any further than you have to.


  #9  
Old December 23rd 04, 06:36 PM
ChipMIK
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boredwild wrote:
Thanks for the warning. Would it seem that the problem is the laser
itself (in which case I would have nothing to lose by adjusting it) or
could it be with another component, and is simply masked by adjusting
the laserpot?

It might the laser wearing out, dirty lens...or the sled/rail the laser
is mounted on that has become misaligned...if possible to re-align the
"rails", using a standard CDROM, find the adjustment with the least
power to laser (use multimeter in ohms measure between the to
side-by-side legs of the pot, looking for a peak on the meter), where
you can adjust the thing to work.

If you had the original reading of the pot, you could try setting it
back & check if you mechanically could bring the thing to work
again...if not & offcourse u as no. 1 has cleaned the lens
carefully...well tweaking is the ting to do, but will prob. only last
for a short time....hey better than a totally dead laser

Hope your not to confused of my weird way of xpression & danish thoughts
brought to english letters he he

Best regards

ChipMIK
  #10  
Old December 23rd 04, 06:57 PM
boredwild
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This is very helpful. There is a factory mark on the pot where it was
originally adjusted, and I moved it about .5mm counterclockwise; I
could reset and measure. Regarding the rails, it does not seem as
though there is any potential for adjustment; they just "clip" into
place.

When you say to adjust the pot using a standard CDROM, I am assuming
you mean a music CD (as this is an audio CD player), or is there some
trick to using a data CD?

 




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