I have the same problem as julietalbot feb 28 2010 in that I have a Denon DN M2300R that will not recognise Disc 1 slot and shows error b2, can anyone help please? cheers Chris.

HI ALL YOU NEED TO DO IS PUT IN A CD/DVD LENS CLEANER CAUSE NOW ITS DIRTY THEREFORE THE LASER IS UNABLE TO READ THE DISC.

It means that the Eject Lock is not functioning on that deck. It should not cause you any problems other than you the fact that you can eject the disc while it is playing or recording so just take care not to press the eject button without stopping what you are doing first.

The lazer is not reading the disc, It is shot.

Will it play the disc,s?

If it shows No Disc error to all CDs, either its Sled Motor [The motor which spins the disc inside], or its optical picku unit has the fault. You have to contact the nearest Denon authorised service center to get it repaired, as Denon uses special type machanism with theirs sets, and it can't be available at open electonic spare part market.

Are you using the correct format of discs? It requires Standard compact disc (12 cm), types CD-TEXT, CD-R, CD-RW (CD-R and CD-RW disks must be finalised before using - but even then will not always be accepted) It will not work with CD+R or CD+RW
If it will not work with ANY CD (including professionally produced CDs) then the lens may need cleaning. Purchase a CD cleaning disk (a computer CD cleaning disk will work fine) pop it in the slot and hit the play button.
You can download the manual here http://www.denondj.com/Assets/Dimages/Products/Manuals/ab8715a8c0d742f0ab8c9afed5bf90e0.pdf?ts=012725

clean the lasers with a damp cotton bud.
take the lid off, unscrew the circut boards, remove carefully some of the connected wire looms 2 get better access, slighly dampen 1 end of a coton bud with plain water, clean the lens through the hole, repeat with the dry end of the cotton bud. re-assemle.

clean the lens...if it does not work replace the lens.

if the cleaning cd don't work then it will need to be cleaned by hand , and if that don't do it then you will need the laser mechanism replaced

electech

Try to change the laser unitKSS-240A (opticals). In most cases problem solved. The "zik-zik" sound is made by the motors in the unit as the laser tries to read the CD.
Caution, after installing the new laserunit remove the short circuits on the laserunit itself. This it put there just to protect the laser from static energie faulure during repair.