"Leonard Caillouet" writes:

"William R. Walsh" m
wrote in message news:Ul0mh.334766$1i1.84177@attbi_s72...
Okay...not that I disagree or anything like that, but why is this
adjustment
provided if you're not supposed to use it when servicing the player? Why
spend the money to include such a thing? Is it for "factory setup only"?

Lots of adjustments are critical in various electronics. What about high
voltage regulation adustments in CRT based sets. Would you just randomly
tweak it up if the pix was weak? Most LP adjustments are not going to do
much beyond shortening the life of the pickup.

The laser power is set at the factory. Only a few components determine
the laser power and they don't really change much with age or use. The
feedback circuit maintains the laser power constant should the output
from the laser diode itself with respect to current descrease. One thing
that can affect it though is that dust, dirt, contamination on the optics
between the laser and the disc and photodiode can result in less optical power
reaching the disc and/or being reflected from the disc to the photodiode.
In this case, if the optics can't be cleaned - which is likely for some of
it - turning up the laser power is the only real option. But it's a last
resort, not a first resort! As has been stated, that's a good way to kill
a perfectly good laser.

--- 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
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