"Sam Goldwasser" wrote in message
...
"Arfa Daily" writes:

wrote in message
...
I don't know if I will ever get this working right, but I sure am
learning a lot.

I'm sure this has to be looking for a reflection before it decides to
starts up the spindle.

I can't see the lens with the CD in. If I put a clear protective disc
in, nothing happens because it sees no reflection.

The unit is a CDP-302, a high end unit. The tag on the laser assy is
BU-1
119712

And from its construction, to replace it might cost the same as what I
paid for the unit new.

Since it will play in any position once started, is it possible the
focus/tracking drive isn't working till it starts and the at rest
position is causing the reflection to totally miss the target.


I can only imagine that to be the case if the disc was not lying flat on
the
turntable for some reason. That laser part number is not familiar to me.
I'll see if I can find some service info on this player, and see if I can
think of anything else that you could reasonably try. It's reaching the
point where you have to be starting to think that it's something obscure
rather than common. An experienced eye might just look at it, and see
immediately what the trouble is. On the other hand, sometimes faults like
this can baffle even the most experienced of us.

I agree it may be obscure and possibly an electronic problem. There are
some differences in the part of the circuit used for the focus seach, so
your hypothesis is at least possible.

What I have done in the past to examine what's happening when it tries
to focus is to cut down a normal CD to just larger than the inner track.
One of those mini-CDs might also work. If you see the lens not moving
up and down very far, then initial focus search may be the problme.

Long ago, I cut a large chunk out of an old CD with a hacksaw. That allowed
me to position the hole such that disc was over the lens, but the lens could
be seen through the hole. i don't know where that disc is now - buried
somewhere deep in the workshop no doubt. These days, I tend to just lift the
deck out, and just watch the lens action by looking under the disc or, if
you can remove the disc clamp to get good access to the top of the laser,
you can just hold a disc over the top of it at about turntable height, and
as parallel to the deck as you can manage. You can usually get the focus
servo to lock, and even 'play' with it by moving the disc up and down. It's
quite fascinating to watch the lens follow the disc as though it was stuck
there with invisible glue. I also have a circular magnet removed from a
scrap deck's disc clamp. this is very useful for sticking a disc down to the
turntable, after removing a disc clamp for eyeball access. You can also
BluTack a disc down at a pinch.

Having had a further think about this problem, could it be that something is
restricting the movement of the sled when the deck is flat ? Most players
will shuffle the laser off the home switch and back on again, just to make
sure that the laser is home, before turning on the laser and starting the
'disc in' initialisation procedure, ending in reading the TOC. If that
shuffle couldn't take place, or was being restricted in some way, then the
system control micro may not be getting the right switch signals to start it
off. If you can get the deck out in your hand whilst keeping it connected,
or otherwise get good visual access to it, try just opening and closing the
drawer, with no disc loaded, and watch exactly what happens - laser shuffle,
laser burning, focus seek etc, then try the same again with the deck tipped,
and see if you can see any difference in what happens. If not, try the same
with a disc loaded.

Arfa