Does it make any noise, even briefly, when you press play? This could indicate slipping as the disc accelerates.
The puck has small rubber dimples underneath. They can become a bit compressed. Hard to see and it may seem like it grips when stationary.
Little balls of blu tack also work well if the Puck needs some help
Not tried blu tak, but i found that sellotape worked on the half-dozen CDs that were giving problems.
I suppose that the 3.5 will eventually fail completely, and I will be forced to let her have my CDX!
I’ll take a look at the puck with a pair of tweezers. Ive tried a few cd’s and no luck.
Thanks
The user manual, whilst unhelpfully silent on the ERR message, does give clear maintenance instructions for the clamp (puck).
Clean the clamp with Blu-tak and/or brush lightly with your finger or a soft cloth.
If you get an improvement then at least you know what the issue was. It could be temporary, in which case get a new clamp (Clamp 3, but you should check). I went through this process about 10 years ago and was lucky. I think it is a common issue, so worth trying.
Here a description and picture of the masking tape solution I posted a while back:
Apart from once needing two layers of tape, I’ve never had this solution not work for any CDs which give the dreaded ERR on my CDX2.
Best of luck,
Mark
I had assumed that the OP had the ERR message on all CDs and they had been fine previously.
Still, the suggestion for thickening thin CDs is worth a try.
Ditto, two different pucks couldn’t cope with some very thin disc centres.
May or may not be relevant and I know that we aren’t supposed to discuss DIY repairs, so I am risking a slapped risk here.
My CDI developed the dreaded ERR. On inspection I found that the transport mechanism mounting screws had worked loose. Quick tighten and problem solved.
I doubt it would be worth getting the CD3.5 repaired. In any event, your SONY is a much better player.
I received my entire Naim system as a gift not long ago so have never listened to the 3.5. I certainly do like the Sony quite a lot. It’s solid and still works flawlessly.
Are you sure? I’ve had a few of the big old Sony ES CD players and while I’ve admired their great finish and overall physical presence, they have generally disappointed in their performance. I so wanted to love them, and try as I did, they just didn’t engage me, and lacked a sense of snap and rhythm. I even bought a Sony SACD player and compared the SACD layer of some dual layer SACDs played on the Sony to the CD layer played on a CD5, the latter being more enjoyable to these ears.
My first ever CD player was a SONY. It was a good machine, beautifully made, one step down from their then top-of-the-range player, which cost squillions. (I think that mine might have had the model number 501, and their top player was the 701.) It didn’t use DIN sockets, of course, so getting a suitable interconnect was a faff.
I had a QUAD system, because I had a yearning to try electrostatic loudspeakers, and QUAD’s CD67 CD player was pretty good.
When Naim brought out their first CD players, a few years after the format was launched, I was able to return to the fold. of the righteous.
That is interesting Richard. Meyer and Moran’s large double blind testing showed that most people could not tell the difference between the the hybrid layers on the same machine. Slightly more preferred the CD layer to the SACD layer. One opinion that I have heard expressed by an audio engineer is that making a machine to play both SACD’s and CD’s involves compromises which do not maximize the potential of both?
Its seems to me, to be a sad state of affairs when a CD player - such as the Naim CD3.5 - cannot be repaired - although I do understand why this is.
In contrast, most Turntables for the same era (Linn LP12) - and from much earlier (Garrard 401) - can still be repaired with relative ease.
Technology… hmm… 
Different machines here RWC, same discs, different layers.
I would occasionally get some ERR messages on my CDX, so I cut a little circular ring out of paper as shown below and it did the trick!
(Hopefully this doesn’t fall foul of forum rules i.e. a modification 
)
It’s fine, although you’re probably better of sticking the paper circle to the discs that have been pressed thinner than redbook, otherwise it will not be optimal for all the other discs pressed top the correct red book standard.
Alternatively get a Clamp 5 and then use it for any problem discs and just be very careful when placing it or removing it from the spindle as it will stick like a limpet.
How much does putting and removing the puck contribute to transport degradation. I seem to remember there are guidelines on how to remove it so that the forces on the transport drive were not so strong
I’ll try citting a paper circle. I wonder if this issue is unique to the 3.5. It seems like if this is a known issue Naim would have offered some support to work around the issue.
Not impressive design work from the vaunted Naim design team though i do like the rest of the hardware.
