Reads cd when cold, skips when warm. Why?

[Ampersand]

My source is a denon dcm-380. Issues with the cd player not reading discs has been well documented. But, I've never seen it broken down - so here goes..

About 1/4 of my cd collection will not play on this player if i've been listening for 15+ minutes. However, the same cds WILL play if i play them at the very beginning of a session (just after i turned the player on for the first time). I can play one of these cds at the very beginning and it will play, and then come back to it (it's a carousel changer) and it won't read the disc.

Turning the player off and immediately back on does not fix the problem.

Just curious if anyone has an explanation for this.

 

[tkam]

I'd bet that the laser is probably dying.

 

[lini]

Ampersand: Considering that the model isn't so old, I'd search for dirty laser optics, badly adjusted laser current, optical head rail lubrication and bad solder joints - roughly in that order. Some to all of that can be done the diy way, depending on your experience, equipment and patience to learn. Point in question is probably how much effort would be worth it, given that the player isn't an overly expensive model - even more so, if you don't diy and rather have it professionally serviced/repaired... I.e., a thorough search for bad solder joints in a workshop might be more expensive than the player, for example.

Greetings from Munich!

Manfred / lini

 

[Ampersand]

Seeing as how i've been considering moving to a single disc player, I'll probably not try to have the unit serviced or do any diy.

I was just curious if there were any scientific reason/explanation for this.

BTW, this has been the case since day 1.

 

[dura]

I'm not familiair with that Denon type but I know several friends who have Denon players and report things like this; sometimes it plays, sometimes it doesn't.
All those players have seperated parts in the drawer, connected with little springs.
They seem to be the culprit, probably chancing the distance between the CD and the laser.
Unfortunately, other then fiddling with the springs, I never heart of an effective solution.

 

[infinitesymphony]

I tried to fix a broken DCM-65 (exactly like DCM-370) this summer, and after months of replacing parts and tweaking, I was no closer to getting it working. Sometimes it would detect the Table of Contents on a CD, and then it might play a track or two before skipping and ultimately failing to read anything.

I tried adjusting the laser, swapping out the motors, replacing the whole laser mechanism, and replacing the ribbon cable that connects the laser mechanism's output to the circuit board; everything short of buying the service manual, a multimeter, a test CD, and an oscilloscope (which would have significantly affected the budget, since I only paid $0.99 plus shipping for the player).

Ultimately, I gave up... Maybe I'll try fixing it some time in the future, since it's still sitting unused under my bed.

 

[lini]

Quote:

Originally Posted by Ampersand (...)I was just curious if there were any scientific reason/explanation for this.(...)

Most probably thermal drift.

Greetings from Munich!

Manfred / lini