View Single Post
  #13   Report Post  
Posted to sci.electronics.repair
Sam Goldwasser Sam Goldwasser is offline
external usenet poster
 
Posts: 244
Default WEIRD problem with CD player

writes:

I have run thru the solders on the drive board and elsewhere.
The drive is fine when it runs and the "tilt" is a specific angle and
repeatable with bumping and jarring having no effect.

I am suspecting that it has something to do with the laser itself
since the fix (tilt) is so repeatable. It is definitely on the deck.
I checked out all the switches and the board on the deck removing and
replacing all connectors.

Apparently the electronics need feedback from the laser to tell it
there is a CD in the deck before it will generate the drive for the
spindle. Is this correct???

Therefore the Laser needs to see a reflection. So if the laser is
tipped, the reflection won't hit the right spot on the assy. I see
only a movement, apparently controlled by coils, that adjusted the
laser along the radius of the CD.

When it does play, I see the sled shaking back and forth as if
following the CD. Shouldn't the laser itself be moving by the coils
mentioned above. I think this deck has three lasers to control
tracking. I have no idea how this works. I only see one lens.


See the CD Player Repair guide at the site below.

The sled should not be shaking back and forth, only the lens. The sled
should just move occasionally to maintain the lens centered withint its
range.

--- 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 is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.