CD player does not recognise some CDs. When placed in the drawer the deck displays "no disc" if another CD player is used the disc works fine

It may be a mechanical or optical detection of the disc being inserted.
The unit need to be seen by a Technician to determine what is wrong with the unit. Lens cleaning is not the first action I would take to resolve this.

There is nothing you can do to repair this, you must remove the deck and send it out for repair at a factory approved repair station.

I have the same problem and have just lived with the B deck for over a year. Just now with nothing to lose, I decided to open it up. I don't have a clue about the inner workings, but was on a mission to at least rescue the 3 discs that were held prisoner. I'm happy to say that not only did I rescue my discs, but I'm listening to a disc in tray 2 right now. All the trays now work. I don't know if my disc was jammed in the player or what the problem was, but it seems the act of removing the disc from the deck made all the difference. If you want to try this, take the 6 black screws out (top 2 on rear panel, 2 on left and 2 on right panel) lift the panel straight up to remove it. you'll see the white framework that houses the trays and the play deck near the rear. In retrospect I should have opened up the play deck first since that may have been the source of the problem. I suggest you try that. There are two tiny screws on each side of the framework. Not sure if you need to remove the two screws with the washer heads. I think they just hold the disc clamp head in place. Again, I'm trying to save you unnecessary work, but remove them if it still doesn't come off. Once you get the top of the deck off, you should be able to access your disc. Take it out, then plug in the player to see if the deck starts to operate. I was very surprised. The belts started spinning and I was hearing the startup sounds I hadn't heard in over a year. Hope this helps

Are you using a disk that the machine can recognise? Some disc players do not recognise certain formats, so it might be worth checking the discs or formats you are using.

Your player lens needs to be cleaned by a lens cleaner...

Simple solution - a CD lens cleaner did the job. $11

in the manual it says that error 12 could be scrached disc or dirty disc the action it says to take is to clean or replace the disc(s). the last thing error 12 could mean is mechanical error, actions for that is to turn your key to the off position and wait for the power to turn off and when it does turn it back on and see if it works, if none of these work then i suggest that your player needs replacing. hope this works for you

The CD player has a sensor that is supposed to detect when a disc is inserted and spin it up etc. yours might be the problem, either it has some loose connections (that you haven't noticed) or it simply misbehaves. Another thing could be the motor itself that somehow 'misses' the spin up signal and needs a 'manual' boost. The best solution in your case is probably to bring it to some lab.