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Denon DCD-800 (circa 90's) CD player - CD spinning back and forth

Immelman

Apr 21, 2022
2
Joined
Apr 21, 2022
Messages
2
Hey all,

Hoping someone knowledgeable about this type of equipment can help, i'm at my wit's end!

I have replaced the belt to allow the CD tray to open and close, which now seems to be working fine.

However, when a CD is fed in, it spins up for 2-3 seconds, and then spins the other way for 2-3 seconds, endlessly.

I've read online that the CD spinning up is a good sign, meaning that the lens is OK (or at least recognizes a CD), so hopefully that's good news!

Now I have investigated a bit further, pulled out my multimeter and can see that I'm getting alternating +5V, -5V tension voltage at the cable end the spindle motor is plugged in, which seems coherent with the behavior.
I've also managed to find a service manual for the thing (in German of course, why make it easy?), and have traced the connection to the servo chip, at which I am getting +2V, -2V, also alternating...

So something is wrong before that stage but I'm just not expert enough to understand where this might be coming from...

Hopefully someone can help!

I've got the service manual PDF if someone thinks they can decipher the thing. I'll keep trying in the meantime.

Video of the issue:
Denon DCD-800

Thank for any help you could provide

Antoine.

[mod edit: replaced tension by the common term voltage]
 
Last edited by a moderator:

Bluejets

Oct 5, 2014
5,989
Joined
Oct 5, 2014
Messages
5,989
Laser cannot pick up the disc by the sounds of that.
Not being read at all.
These devices are factory set and cannot be fiddled with.
Some may say, clean the lens but never seen this work yet.
Only alternative would be replace the drive as a unit.
 

Harald Kapp

Moderator
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Nov 17, 2011
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Nov 17, 2011
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The CD should imho spin in one direction only.
Does the CD come to full speed or does the CD slip on the pickup (easy to hear as this will make a scraping sound)? I've had luck with cleaning the pickup disc and the laser lens with alcohol (the medicinal type for external use, not the drinkable type for internal use ;)) and a soft cotton swab ("Wattestäbchen").
 

Immelman

Apr 21, 2022
2
Joined
Apr 21, 2022
Messages
2
Hey all, thanks for your inputs!

I've since taken diagnostics a little bit further. Using a multimeter and a service manual I found in the net (in German ) I traced the spindle motor power feed and measured that's it's sending +5V/-5V alternatively every few seconds which explains the CDs skinning behavior.

Unfortunately it seems like the issue is with the logic circuit or some component before the IC so that's gonna be a tough one to fix ...
 
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