Hi All,
I noticed my Roksan CD started skipping the other month, extremely intermittent, only the very occasionally jump on a song and nowhere in particular (ie not the same length trough every CD or related to particular CDs), but still extremely frustrating when listening!
So after a bit of forum surfing I decided to remove the cove and mechanism and add a little white grease to the moving parts that could have become dry over time. this seems to be the least invasive but most cost effective first try at a fix.
So my first question was going to be - will I be able to open the mechanism (CD tray) without power to get to the gears and rails more easily. I have the mechanism out but I cant figure out how to get it open and don't want to force it and break something. ( this might be a trivial question for you all but this is the first player I've opened that not a PC CD drive 🙂 )
Now my second more pressing question is - Once I looked back into the case after removing the mechanism there was, what appears to be, a tiny ball bearing sat in the bottom of the case. I've taken the best picture I could with a case screw for size reference but cant upload for some reason (ill add them later), with a vernier it measures 0.54mm. Does anyone have any idea where this could be from and could this be the reason for the occasional jump whilst playing?
Thanks in advance,
Sam
I noticed my Roksan CD started skipping the other month, extremely intermittent, only the very occasionally jump on a song and nowhere in particular (ie not the same length trough every CD or related to particular CDs), but still extremely frustrating when listening!
So after a bit of forum surfing I decided to remove the cove and mechanism and add a little white grease to the moving parts that could have become dry over time. this seems to be the least invasive but most cost effective first try at a fix.
So my first question was going to be - will I be able to open the mechanism (CD tray) without power to get to the gears and rails more easily. I have the mechanism out but I cant figure out how to get it open and don't want to force it and break something. ( this might be a trivial question for you all but this is the first player I've opened that not a PC CD drive 🙂 )
Now my second more pressing question is - Once I looked back into the case after removing the mechanism there was, what appears to be, a tiny ball bearing sat in the bottom of the case. I've taken the best picture I could with a case screw for size reference but cant upload for some reason (ill add them later), with a vernier it measures 0.54mm. Does anyone have any idea where this could be from and could this be the reason for the occasional jump whilst playing?
Thanks in advance,
Sam
It all depends what the mechanism type is but you can normally open the tray by careful poking of the appropriate gear with a tiny screwdriver or by simply applying a 1.5v battery to the tray motor.
One tip is that is can be easiest to begin with the drawer open, then dismantle the player/mech.
No idea on the ball bearing without knowing the mech used. Philips swing arm types had them... can't just recall any other common ones.
If it is a CDM12.1 or 12.4 type then the grease becomes granular over time. Easy fix but these need stripping right down to their component parts and all of them cleaning and then relubricating with a plastics compatible grease.
One tip is that is can be easiest to begin with the drawer open, then dismantle the player/mech.
No idea on the ball bearing without knowing the mech used. Philips swing arm types had them... can't just recall any other common ones.
If it is a CDM12.1 or 12.4 type then the grease becomes granular over time. Easy fix but these need stripping right down to their component parts and all of them cleaning and then relubricating with a plastics compatible grease.
Hi! The bearing ball that you saw can be the cause of malfunctioning. I don't know this cd. Which mechanism uses?
A picture would be helpful.
A picture would be helpful.
Thanks for the replies both,
I have attached a pic with the cover off before I realised I left the CD in
, and one of the mechanism.
So update - I think that ball bearing may actually have been a tiny ball of solder, its not magnetic and in some photos looks to have a tiny flat spot! is this a common thing? Seems odd but it looks like such a small bearing and I cant see anywhere it would have come from.
Anyway i've cleaned and re-greased the gears in the mechanism and its all back together and moves freely. Its playing at the moment and fingers crossed it's not jumped yet! Ill update again if it does!!
Thanks again,
Sam.
I have attached a pic with the cover off before I realised I left the CD in
, and one of the mechanism.So update - I think that ball bearing may actually have been a tiny ball of solder, its not magnetic and in some photos looks to have a tiny flat spot! is this a common thing? Seems odd but it looks like such a small bearing and I cant see anywhere it would have come from.
Anyway i've cleaned and re-greased the gears in the mechanism and its all back together and moves freely. Its playing at the moment and fingers crossed it's not jumped yet! Ill update again if it does!!
Thanks again,
Sam.
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New Update,
First CD (Pink Floyd Echos) - all fine.
Second CD (Foo Fighters ESPG) - Struggled to read the disc at the start (had to reload it a couple of times for it to read the track and time) but then played fine until the middle of track 6 then it jumped part way through and continued playing until the end of the CD??
Does anyone have any ideas what could be going on?
Sam.
First CD (Pink Floyd Echos) - all fine.
Second CD (Foo Fighters ESPG) - Struggled to read the disc at the start (had to reload it a couple of times for it to read the track and time) but then played fine until the middle of track 6 then it jumped part way through and continued playing until the end of the CD??
Does anyone have any ideas what could be going on?
Sam.
Bits of solder are not unknown so if that is what it is then its nothing to worry over.
As to the fault... you absolutely must look at the RF signal with a scope. Until you have done that its all guesswork. It just tells you so much, amplitude, bounce, jitter and just overall 'goodness' of the clarity of the signal. A player that is marginal will often play some discs and struggle with others.
Have a read at this:
Sony CDP790 and KSS240 Restoration Project
If it jumps at the same sort of area on the disc then you could monitor the tracking error voltage and look at the sled motor drive voltage. If the sled sticks the voltage will increase across the motor until there is sufficient torque to jolt the sled free.
As to the fault... you absolutely must look at the RF signal with a scope. Until you have done that its all guesswork. It just tells you so much, amplitude, bounce, jitter and just overall 'goodness' of the clarity of the signal. A player that is marginal will often play some discs and struggle with others.
Have a read at this:
Sony CDP790 and KSS240 Restoration Project
If it jumps at the same sort of area on the disc then you could monitor the tracking error voltage and look at the sled motor drive voltage. If the sled sticks the voltage will increase across the motor until there is sufficient torque to jolt the sled free.
Hi Mooly - Thanks for your help!
I have found a scope and picking it up this evening so hopefully should get some usable readings. Forgive me for being ignorant here but i'm assuming I also need the Audio Signals Disc you use in the link for the scope readings?
Thanks again,
Sam.
I have found a scope and picking it up this evening so hopefully should get some usable readings. Forgive me for being ignorant here but i'm assuming I also need the Audio Signals Disc you use in the link for the scope readings?
Thanks again,
Sam.
Any decent quality 'Red Book' standard disc (so any bought music CD) will give the exactly the same RF signals. Try a few because very very occasionally you can get one that is more reflective than normal and also of course, less reflective. 98 out of 100 will all be the same and good.
The official discs (as well as having audio tones etc on them) are just normal discs but manufactured to high and guaranteed tolerance for reflectivity, disc thickness, eccentricity etc. You don't need them for all normal repair and test work.
Never use CDR or CDRW for any tests.
The official discs (as well as having audio tones etc on them) are just normal discs but manufactured to high and guaranteed tolerance for reflectivity, disc thickness, eccentricity etc. You don't need them for all normal repair and test work.
Never use CDR or CDRW for any tests.
Judging from those photos, that is one of the cheaper-style CD mechanisms.
Those white plastic gears are a dead giveaway.
In the shop, we used to call them " recycled milk-bottle plastic", and they are found in lots of things, VCR's included.
I suspect that the motor shaft gear may be split, which seperates the teeth at that point, and when meshing with the larger gear, hangs up due to binding.
I've seen this plenty of times, and the only solution is to replace the motor gear.
Remove the shroud over those gears, and with a magnifier, inspect the motor gear carefully.
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It's been a while since the last post but I finally got around to getting the scope attached to check what's going on.
I've attached the 'eye pattern' but this is as clear as I could get it . I've not seen one myself before only images of others online and this one looks pretty messy in comparison?
On another note I also contacted roksan for the test procedure and adjusted the pot for as this was ever so slightly off and now the player seems to be playing just fine. No skips as of yet and reads all CDs I've loaded.
Perhaps this was the issue all along?!
Thanks for you help all - info on the wether the eye pattern is correct would still be appreciated!
Sam
I've attached the 'eye pattern' but this is as clear as I could get it . I've not seen one myself before only images of others online and this one looks pretty messy in comparison?
On another note I also contacted roksan for the test procedure and adjusted the pot for as this was ever so slightly off and now the player seems to be playing just fine. No skips as of yet and reads all CDs I've loaded.
Perhaps this was the issue all along?!
Thanks for you help all - info on the wether the eye pattern is correct would still be appreciated!
Sam
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Look at the images I posted in the link in post #6. The eye pattern in those shots is a good example and shows a clear and steady pattern with no horizontal or vertical jitter. It should look just like those on a scope like yours.
Is your scope triggered correctly? AC coupling and no HF reject selected.
Is your scope triggered correctly? AC coupling and no HF reject selected.
@jean-paul - I did clean the top of the lens when I first disassembled to re-grease the mechanism, might be worth another shot though!
@Mooly - I should have taken a better picture with the scope dials showing! - It's an old Gould OS300 for reference - I'll set it up and take another photo.
I did read through your post, it was very informative and along with the info from Roksan allowed me to get the player to a point where its now working 🙂 . The eye pattern you posted in your thread looked so clean in comparison to the one I have, it leads me to believe it may be user error with the scope rather than an error with the player?
Thanks again for your help, it is very much appreciated.
Sam
@Mooly - I should have taken a better picture with the scope dials showing! - It's an old Gould OS300 for reference - I'll set it up and take another photo.
I did read through your post, it was very informative and along with the info from Roksan allowed me to get the player to a point where its now working 🙂 . The eye pattern you posted in your thread looked so clean in comparison to the one I have, it leads me to believe it may be user error with the scope rather than an error with the player?
Thanks again for your help, it is very much appreciated.
Sam
The timebase speed is correct (0.5uS/div)... it should look way better than that.
The trigger switches don't have HF reject but have a 'TV' mode which was for old fashioned analogue TV and its frame and line sync pulses. So you want those switches NOT selected and also select just Channel #1 as the trigger channel.
If both CH1 and CH2 are pushed in then it selects external trigger which you don't want.
With the switches correct see if very carefu adjustment of the scopes trigger control will lock the waveform. If it won't then you can also adjust the 'Var Sweep' knob a little to see if that will get it to lock.
The trigger switches don't have HF reject but have a 'TV' mode which was for old fashioned analogue TV and its frame and line sync pulses. So you want those switches NOT selected and also select just Channel #1 as the trigger channel.
If both CH1 and CH2 are pushed in then it selects external trigger which you don't want.
With the switches correct see if very carefu adjustment of the scopes trigger control will lock the waveform. If it won't then you can also adjust the 'Var Sweep' knob a little to see if that will get it to lock.
Hi Mooly - All switches as you suggest but still no luck clearing it up.
the 'var sweep' does make a difference to the scope but for the worse not better - it feels as if the scope needs another step beyond 0.5us to get a lock?
Trigger control Makes no difference to the waveform at all regardless of which trigger Chanel is selected 🙁 ..
Do you think I've perhaps gone and got myself a faulty scope?
the 'var sweep' does make a difference to the scope but for the worse not better - it feels as if the scope needs another step beyond 0.5us to get a lock?
Trigger control Makes no difference to the waveform at all regardless of which trigger Chanel is selected 🙁 ..
Do you think I've perhaps gone and got myself a faulty scope?