Skipping CD Player: DIY Solutions?

[Conchis]

Thought I'd call on the technical expertise of the forum to resolve a problem I have...

My CD player (Cambridge Audio Azur 640c) has started skipping: it begins around the one-minute mark on the first track of a CD and then continues. The fault seemed to develop overnight. I'm using my blu-ray player as backup but would like to get the CD player up and running again.

Those lens cleaning discs are useless, imo but I've read about a DIY lens cleaning process that involves diluted alcohol and delicate finger operations. Has anyone tried anything like this - and, if so, can you advise?

Cheer! :)

[Bryn]

How long have you had the player? If you opted for Richer Sounds extended guarantee and it is still valid, might be worth taking it to one of their branches to get it looked over.

[Cockney Sparrow]

No experience of laser lens cleaning other than the discs, sorry. I hope you get some knowledgeable advice here (of course).
Meanwhile you could search You Tube, and, separately,Google and see what you find. Its my first recourse to DIY repairs, ever since I got a flatscreen TV up and running (it had a continuously scrolling screen image) by searching on the brand and model number. All I had to do was disconnect one connection onto an electronics board.

[Conchis]

How long have you had the player? If you opted for Richer Sounds extended guarantee and it is still valid, might be worth taking it to one of their branches to get it looked over.

I did get it from Richer Sounds but (I'm afraid) didn't avail myself of their extended warranty. A stupid thing not to do, I know. Mind you, I bought it in 2009, so possibly out of warranty by now, anyway.

[Petrushka]

Presumably this is happening on every disc you play? Personally, I've found those lens cleaning discs pretty useful when I've needed one. Don't want to sound like teaching anyone to suck eggs but one has to dispose of the obvious first as this could be nothing more than a speck of dust or a stray hair lodged in the machine.

[Conchis]

Presumably this is happening on every disc you play? Personally, I've found those lens cleaning discs pretty useful when I've needed one. Don't want to sound like teaching anyone to suck eggs but one has to dispose of the obvious first as this could be nothing more than a speck of dust or a stray hair lodged in the machine.

Yes: it's on every disc, including my one lens-clearning disc, which - admittedly - I hadn't used for many years.

I've thought about unplugging it, lifting it up and shaking it about a bit: if a stray hair is the problem that might do the trick!

[Gordon]

Given it's every disc we can assume, I think, that it is something within the machine. When this happens do you just put in a disc and then play from the start? Once playing, even if skipping, does it continue to the end or does it eventually give up altogether and stop? Is the machine used a lot? We know that the problem has just appeared after presumably working well? When you say it skips do you mean that sections of audio are lost rather like what happens in a fast forward or is it just some muting?

The fact that it at least plays the disc for about a minute tells us that the laser scanner mechanism can find the TOC near the centre and then proceed to track 1. That suggests that the lens is clean enough although a clean would do no harm. The machine is a tray loader and so does not allow access to the mechanism without taking the cover off which probably invalidates any warranty left [none anyway]. There is no guarantee that you'll be able to access the lens that way but it may let you see if there is any foreign matter [eg hairs as suggested] causing the problem. This seems unlikely but if you can see the lens a VERY careful clean might be feasible by hand.

The symptoms suggest that the machine can read data from the track but is finding that the track following servo isn't keeping up. It's had to know what type of track following servo is used in this machine. So what about asking the machine to go directly to a track somewhere in the middle say 5 of a 10 track disc? The TOC can be read so it should know where to go to. If that plays [not all of it, just to see if it plays at all] then see for how long. Then try to play the last track directly and then all the others in turn. OR use the track select buttons to move from track to track at random preferably exercising the whole set of tracks from start to end and back again The purpose of this is to make the sled that carries the lens system to move quickly along its carriage so that any obstruction is possibly removed. Another way of doing this is to use the fast forward/back buttons to make the sled move quickly backwards and forwards. If this doesn't work then perhaps we may have to suspect the laser.

In the handbook the suggested solutions to "skipping" are: to suspect a dirty or scratched disc [not so or this case] OR that vibration is affecting the machine. From your description it's been fine until more or less now so that seems unlikely but have you moved it lately? IF you do try the "shaking it" solution [or the Engineer's Thump] don't be too energetic as the player mechanism is mounted on an isolating suspension which could be damaged.

[Andrew Slater]

It could be dried-up grease on the head drive mechanism, as it was on mine. Unfortunately it's usually quite difficult to get at to clean and re-grease.

[richardfinegold]

Given it's every disc we can assume, I think, that it is something within the machine. When this happens do you just put in a disc and then play from the start? Once playing, even if skipping, does it continue to the end or does it eventually give up altogether and stop? Is the machine used a lot? We know that the problem has just appeared after presumably working well? When you say it skips do you mean that sections of audio are lost rather like what happens in a fast forward or is it just some muting?

The fact that it at least plays the disc for about a minute tells us that the laser scanner mechanism can find the TOC near the centre and then proceed to track 1. That suggests that the lens is clean enough although a clean would do no harm. The machine is a tray loader and so does not allow access to the mechanism without taking the cover off which probably invalidates any warranty left [none anyway]. There is no guarantee that you'll be able to access the lens that way but it may let you see if there is any foreign matter [eg hairs as suggested] causing the problem. This seems unlikely but if you can see the lens a VERY careful clean might be feasible by hand.

The symptoms suggest that the machine can read data from the track but is finding that the track following servo isn't keeping up. It's had to know what type of track following servo is used in this machine. So what about asking the machine to go directly to a track somewhere in the middle say 5 of a 10 track disc? The TOC can be read so it should know where to go to. If that plays [not all of it, just to see if it plays at all] then see for how long. Then try to play the last track directly and then all the others in turn. OR use the track select buttons to move from track to track at random preferably exercising the whole set of tracks from start to end and back again The purpose of this is to make the sled that carries the lens system to move quickly along its carriage so that any obstruction is possibly removed. Another way of doing this is to use the fast forward/back buttons to make the sled move quickly backwards and forwards. If this doesn't work then perhaps we may have to suspect the laser.

In the handbook the suggested solutions to "skipping" are: to suspect a dirty or scratched disc [not so or this case] OR that vibration is affecting the machine. From your description it's been fine until more or less now so that seems unlikely but have you moved it lately? IF you do try the "shaking it" solution [or the Engineer's Thump] don't be too energetic as the player mechanism is mounted on an isolating suspension which could be damaged.

I have a machine that does exactly what the OP player does. Mine is a Denon CD/SACD player that starts skipping at the one minute mark. The machine was super ceded when I bought the Oppo 105 but I held onto it because I really enjoyed it's warm sound. It is also off warranty and I have removed from the rack and was about to toss it but now I may reinsert it and follow these suggestions.

[Conchis]

Given it's every disc we can assume, I think, that it is something within the machine. When this happens do you just put in a disc and then play from the start? Once playing, even if skipping, does it continue to the end or does it eventually give up altogether and stop? Is the machine used a lot? We know that the problem has just appeared after presumably working well? When you say it skips do you mean that sections of audio are lost rather like what happens in a fast forward or is it just some muting?

The fact that it at least plays the disc for about a minute tells us that the laser scanner mechanism can find the TOC near the centre and then proceed to track 1. That suggests that the lens is clean enough although a clean would do no harm. The machine is a tray loader and so does not allow access to the mechanism without taking the cover off which probably invalidates any warranty left [none anyway]. There is no guarantee that you'll be able to access the lens that way but it may let you see if there is any foreign matter [eg hairs as suggested] causing the problem. This seems unlikely but if you can see the lens a VERY careful clean might be feasible by hand.

The symptoms suggest that the machine can read data from the track but is finding that the track following servo isn't keeping up. It's had to know what type of track following servo is used in this machine. So what about asking the machine to go directly to a track somewhere in the middle say 5 of a 10 track disc? The TOC can be read so it should know where to go to. If that plays [not all of it, just to see if it plays at all] then see for how long. Then try to play the last track directly and then all the others in turn. OR use the track select buttons to move from track to track at random preferably exercising the whole set of tracks from start to end and back again The purpose of this is to make the sled that carries the lens system to move quickly along its carriage so that any obstruction is possibly removed. Another way of doing this is to use the fast forward/back buttons to make the sled move quickly backwards and forwards. If this doesn't work then perhaps we may have to suspect the laser.

In the handbook the suggested solutions to "skipping" are: to suspect a dirty or scratched disc [not so or this case] OR that vibration is affecting the machine. From your description it's been fine until more or less now so that seems unlikely but have you moved it lately? IF you do try the "shaking it" solution [or the Engineer's Thump] don't be too energetic as the player mechanism is mounted on an isolating suspension which could be damaged.

If I play a disc from the end (say, track 20 on a 20 track disc), it plays without interruption. I've tried working backwards on the tracks, but when we reach, say, about track 8, the skipping starts again.

Thanks for your detailed advice, though. More and more, I'm inclined to think it's a laser problem.

[Conchis]

Also - the player skips but doesn't 'give up' on the track. You don't get any more than 4 seconds of 'continuous' play, though.

[Gordon]

If I play a disc from the end (say, track 20 on a 20 track disc), it plays without interruption.

Curiouser and curiouser!! How strange. That suggests that the TOC reading and subsequent finding of the track entry points is good, right out to the edge of the disc where issues like disc warp, eccentricity etc can be very trying for both servos and, once there, is able to read good data consistently. Given the track pitch on a CD is 1.6 microns this is quite a feat - think of the run-out in the revolving bearing and the disc hole punching accuracy!! That means that the sled motion is likely to be good too, at least in the region where the outer tracks are, otherwise it wouldn't be able to get the accuracy to place the reading spot in the right places. It seems to do that for all tracks even if some in mid disc then skip. That suggests disturbance to the track following servo. About 4 seconds of good audio between breaks - track hops? - means several revolutions of the disc. The RPM in the middle is about 300 ie 5 per second so 4 seconds is about 20 revs or tracks. The response time of the servos has to be much faster than that.

I've tried working backwards on the tracks, but when we reach, say, about track 8, the skipping starts again.

The issue seems to be mid disc suggesting that something about the carriage reading head movement servo and/or the focus servo is being interfered with. This doesn't rule out some kind of obstruction or lubrication issue [as #8 above] in the middle of the sled transit path. Perhaps a lot of exercise with the track selector repeatedly moving between the middle tracks will improve matters given time? - long shot perhaps.

Thanks for your detailed advice, though. More and more, I'm inclined to think it's a laser problem.

It could be the laser and/or lens, but I'd suggest that because it is fine at the very start and at the outer tracks that may not be the case.

PS afterthought: what if something is fouling the spindle "turntable" platter? It wouldn't take much to get outside the mechanical tolerances. That would make all discs rotate oddly but then the challenge would be nearer the edge, which seems to work, not the middle or inside.

I googled "CD skipping" and found this posted in July 2011, no further posts on the subject:

"Well, I ran a Memorex cleaning disc through the CD player and the voice on the cleaning CD that prompted me through the process was skipping a lot. But I just let it run and after running it I played the CD that was skipping and it played fine. The next CD I tried, the player started skipping again, so I ran the cleaning CD several times. The second offending CD is playing fine now, but I suspect there may be something more going on. An alignment problem maybe. We'll see how it performs over the next several days.

btw, I'm running a Cambridge Asur 640C, three years old". The machine is only 3 years old so, probably, it is not the laser failing but something else. Could be a generic issue?

I think that most cleaning discs have a short brush glued to the disc and that passes over the lens every revolution for several seconds, or even minutes, presumably at such a height that it just touches the lens surface gently. There is a risk that the clearances are such that it can jolt the lens mount too and that may be good or bad. Typical reading clearance between the lens surface and the disc is about 1.4mm which gives an idea of how long the brush hairs need to be. If they aren't the right length they could miss touching the lens and not do any cleaning!!! If they are too long they could do damage. If the cleaning disc is warped then it could do both depending on the phasing of the brush in relation to the lens position so the best place for the brushes is nearest the centre!!

On a completely different aspect of the spec of the offending machine, I note that the THD power level [-92dB] is higher than the DR spec given as -105dB!! Work that one out!! The jitter spec is average at around 300psec ["correlated" it says so what does that mean] and could be better, ideally about a tenth of that. Anyway in either case the test conditions are not stated so these numbers are somewhat meaningless.

[Serial_Apologist]

Thought I'd call on the technical expertise of the forum to resolve a problem I have...

My CD player (Cambridge Audio Azur 640c) has started skipping: it begins around the one-minute mark on the first track of a CD and then continues. The fault seemed to develop overnight. I'm using my blu-ray player as backup but would like to get the CD player up and running again.

Those lens cleaning discs are useless, imo but I've read about a DIY lens cleaning process that involves diluted alcohol and delicate finger operations. Has anyone tried anything like this - and, if so, can you advise?

Cheer! :)

I had a similar problem with my cheap Sony CDP-M12, which I bought more years ago than I can remember; and the problem likewise started a few weeks after I had bought it, discouraging me from buying more than a few CDs for a long time. Then about a year ago a disturbing screeching sound was emitting from inside the machine, and I decided to do what the manufacturers tell you not to do under any circumstances, remove the outer housing and look inside. Like yourself I was having no joy with the lense cleaning disc, so the first thing I did was to clean the lense with meths on a clean cloth. I then gave a couple of squirts of Kontakt 60 fluid (obtainable from any good electrical components retailer on order) where the spindle underneath the revolving turntable is seated, and since then, apart from a couple of occasions when skipping has ocurred due either to slight damage to the CD or dirt on it, have had no problerns whatsoever - a perfect solution! As another has suggested, the age of your equipment does not suggest problems with the laser itself. One important word of warning: do not touch any part of the inside; it is all live, as I quickly discovered!

Best of luck!