I have a Denon UD-M5 3 CD player that at first sight appears to have a Lasar problem in that it will not play CDs. The Amplifier is working OK when the unit is operationg in the Tuner mode. I have noticed that the head is moving, hunting for the start position on what ever disc and track it is commanded to play, however, it does not appear to pick up alignment information. If I persist , then the player bursts into sound occassionally, playing faultlessly untill the end of the disc is reached. It will also always indicate correctly the number of tracks that any one disc has indicating that it is able to read the indexing sector of each disc. although it has problems in locating the start position. Can anyone please help in A. identifying what the problem is
B. Suggest how the unit can be re-aligned if that is the problem

I have noticed that the unit does not appear to have any drive belts that might slacken. It also has a very complex disc load mechanism.

Many thanks for any help you can give.

ibbotsnm wrote:
I have a Denon UD-M5 3 CD player that at first sight appears to have a
Lasar problem in that it will not play CDs. The Amplifier is working
OK when the unit is operationg in the Tuner mode. I have noticed
that the head is moving, hunting for the start position on what ever
disc and track it is commanded to play, however, it does not appear
to pick up alignment information. If I persist , then the player
bursts into sound occassionally, playing faultlessly untill the end
of the disc is reached. It will also always indicate correctly the
number of tracks that any one disc has indicating that it is able to
read the indexing sector of each disc. although it has problems in
locating the start position. Can anyone please help in A.
identifying what the problem
is
B. Suggest how the unit can be re-aligned if that is
the problem

I have noticed that the unit does not appear to have any drive belts
that might slacken. It also has a very complex disc load mechanism.

Many thanks for any help you can give.

I had an old Technics player (only) which had the same sort of problem. I
*slightly* tweaked the PLL trimmer and cured it. It's still a little picky
about what disk it wants to play, sometimes; and is more prone to skipping
than I'd like. It does work 98% of the time now, though, compared to about
10% before.

If you go this route, do a thorough cleaning first, that alone may fix it.
Then mark *everything* so that you can get it back to square one in case of
no improvement. Only make almost infinitesmal adjustments and check for
functionality after each tweak. If you get it working, try to triangulate
the proper range of adjustment by continuing to go 'too' far, and then back
off to the middle of the range between not working in one direction, and not
working in the other.

I didn't think I had anything to lose, and was ready to chuck the thing if
it didn't work out. Instead, I got a (mostly) functional unit which has
worked for many years with just one small tweak...seriously, I hit it the
very first time...about a 5 degree turn of the pot.

YMMV...oh yeah, be sure to read the FAQ on CD repair before you do anything.

jak

Thanks JAK for your swift and very helpful reply. I have just sent off for the service manual for the Denon so hopefully I will be able to identify the PLL circuitry when it arrives.

Norman

ibbotsnm wrote:
I have a Denon UD-M5 3 CD player that at first sight appears to have a
Lasar problem in that it will not play CDs. The Amplifier is working
OK when the unit is operationg in the Tuner mode. I have noticed
that the head is moving, hunting for the start position on what ever
disc and track it is commanded to play, however, it does not appear
to pick up alignment information. If I persist , then the player
bursts into sound occassionally, playing faultlessly untill the end
of the disc is reached. It will also always indicate correctly the
number of tracks that any one disc has indicating that it is able to
read the indexing sector of each disc. although it has problems in
locating the start position. Can anyone please help in A.
identifying what the problem
is
B. Suggest how the unit can be re-aligned if that is
the problem

I have noticed that the unit does not appear to have any drive belts
that might slacken. It also has a very complex disc load mechanism.

Many thanks for any help you can give.

If not done already, certainly the lens should have a proper cleaning.

Mark Z.