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Denon CD Player/Receiver UD-M5

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.

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ibbotsnm
Reply to
ibbotsnm
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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

Reply to
jakdedert

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

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ibbotsnm
Reply to
ibbotsnm

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

Mark Z.

Reply to
Mark D. Zacharias

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