My denon dn-d 6000 goes off and on and would not play

No it is only a player, not a burner.

Denon DN-T620 Operating Instructions Manual - ManualsLib

ManualsLib https://www.manualslib.com > ... > DN-T620

View and Download Denon DN-T620 operating instructions manual online. CD/cassette combi-deck. DN-T620 cassette player pdf manual download.

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you want expert opinion free LOL that does not happen .we are mostly diy fixers and do not get paid

http://www.djresource.eu/News/news/133/New-Firmware-Denon-DN-S1000-3500-4500-6000/

sounds like the optical pickup (laser) has gone bad. Would have to be replaced.

HOLA TENGO UN DENON 1200 ME SALE AL ENCENDERLO ERROR SYSTEM ME PUEDEN AYUDAR PORFAVOR NO SE QUE ES

Place a blank CD-R into the tray on the right side and allow the DN-C550R recognize it as a blank cd and prepare it for recording. Now you can record. Is that what you're looking for?

check this site, (its spanish)http://www.djmania.es/tienda/advanced_search_result.php?keywords=Denon+DN-S&x=0&y=0&gclid=CMH5lcrz454CFUQA4wodx0iCIA or http://www.instrumentalparts.com/denon-parts.html (international)

Try this:
1. While holding "Title", Press Stop to enter what Denon calls "presetting" mode.
2. Press Track Search Reverse or Track Search Forward until you get to 20, which is the presetting mode for Single/Continuous Play.
3. Press Play to toggle between Continuous and Single Play.
4. Press Stop to exit Presetting Mode.
Hope this works! I just finished a belabored job without Single Play on this unit. I have been searching for the answer too. I don't have access to the deck to try it, but I think this will do the job.

Then the format can't be read by the MAC, what reason this is I have no idea.

The owners manual references turning the servo on and off on page 8

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Good luck... Happy to help you further if things get complicated. A "FixYa" rating for this would help my profile. Thanks