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From: firstname.lastname@example.org (email@example.com)
Subject: Re: CDRW does not read cds
Date: 26 Sep 2002 15:57:32 -0700
NNTP-Posting-Date: 26 Sep 2002 22:57:33 GMT
Chuck Simmons wrote in message news:<3D926F44.A8786603@webaccess.net>...
> "N. Thornton" wrote:
> > firstname.lastname@example.org (email@example.com) wrote in message news:...
> > > Hello,
> > >
> > > I have a panasonic (matshita/matsushita) CDRW , model CW-7585, that
> > > was working fine on winXP Pro and Roxio Easy cd creator 5 platinum.
> > >
> > > Since yesterday it won't regognize cd's blanks or not. I opened it to
> > > see if I could fix it using the extremely helpful instructions at
> > > http://www.repairfaq.org/REPAIR/F_cdfaq.html. This is what I found:
> > > Whenever I close the tray, (with/without a cd in it), the pickup moves
> > > back and forth on the rack, positions at a specific location and then
> > > stops. Then nothing happens. (Normally, the cd should start spinning).
> > > About the laser, I could not see any red spots in a dark room,
> > > whenever I closed the tray (with/without a cd in). Maybe the absence
> > > of a cd did not power on the laser, and its appearance covered the
> > > laser beam.
> > Stop. You will permanently damage your eyesight like this. Do not play
> > like this with cdrom lasers, nor cdrw lasers. Read up on it if you
> > doubt me. It doesn't sound like youre taking the necessary precautions
> > while working with a dangerous laser.
> Don't blow this completely out of proportion. The CD read power we use
> in my lab is between 500 microwatts and one milliwatt. It is best not to
> look directly into the lens but there is no particular problem with
> scattered light. I have to operate CD and DVD devices open in order to
> make measurements including optical power output. Write power is more
> problematic and eye protection should be used when measuring write
> > If the pickup moves but the spindle doesnt turn, the laser focus is
> > not the issue. Possibles are the sensor not detecting the CD is
> > present, or spindle motor is dead, or its drive cct. There are many
> > other possibles of course.
> Many CD and DVD devices use focus to decide if there is a disk inserted.
> There is no other sensor in most. If a focus region cannot be found, the
> drive assumes there is no disk. A CD drive can actually focus and track
> without spinning the disk. Focusing on a stopped disk is useful but
> tracking vibrations at one spot is a little futile. DVDROM can focus on
> a stopped disk but cannot track. Anyway, if the lens does not do a
> couple of "pushups" when the drive is turned on, it is probably not
> bothering to look for a disk. The sledge moving to the ID at power up
> and "tray open" is a feature. If the sledge is not at the ID, in many
> units the tray interferes with the sledge when it opens or closes.
> Moreover, the spiral on CDs and on the first layer of a DVD is always
> outward so the drive must start at the ID.
If I got this well, this poster is suggesting that the fault is at the
focus mechanism? If so, what are the possible (SAFE) solutions to it?
I suspect that I'm better off buying a new CDRW.
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