Marantz CD48 noises. Please help.

[rocker65]

Hi All,
This is my first post on joining DiyAudio.
My Marantz CD48, which I have had from new but which has only had light use, is making a scraping sound when playing as though something that is spinning is rubbing against something else. It is slowly getting louder and has just, for the first time, mistracked.
Q1 Is this indicative of any known faults. If so what is it and what is the cure?
Q2 If not a known fault what should I check and how? Are there any "Do Not's" to be heeded.
Q3 In a worst case scenario requiring that a replacement transport unit, or whatever, is required would these still be obtainable in the UK and from where.
Q4 would there be a later, or upgraded, or alternative unit that could, or should, or would have to be, fitted.

Sorry for going on so but I realy do need help.

Please note that a DIY repair is neccessary due to financial cramp.

Many Thanks

[rocker65]

Originally Posted by rocker65

Hi All,
This is my first post on joining DiyAudio.
My Marantz CD48, which I have had from new but which has only had light use, is making a scraping sound when playing as though something that is spinning is rubbing against something else. It is slowly getting louder and has just, for the first time, mistracked.
Q1 Is this indicative of any known faults. If so what is it and what is the cure?
Q2 If not a known fault what should I check and how? Are there any "Do Not's" to be heeded.
Q3 In a worst case scenario requiring that a replacement transport unit, or whatever, is required would these still be obtainable in the UK and from where.
Q4 would there be a later, or upgraded, or alternative unit that could, or should, or would have to be, fitted.

Sorry for going on so but I realy do need help.

Please note that a DIY repair is neccessary due to financial cramp.

Many Thanks

Hi All.
I have taken the cdp appart.
The lens was a bit cloudy so I cleaned that. I could not find anything rubbing when spinning bits by hand but under power it can plainly be heard. On swithching off every thing is perfectly quiet on the spin down.
Can anyone put forward any ideas as to what may be causing the noise.
On reassembly the unit now tracks every thing OK except Mike Oldfields Tubular Bells. Very strange.

Rod

[rocker65]

Originally Posted by rocker65

Hi All.
I have taken the cdp appart.
The lens was a bit cloudy so I cleaned that. I could not find anything rubbing when spinning bits by hand but under power it can plainly be heard. On swithching off every thing is perfectly quiet on the spin down.
Can anyone put forward any ideas as to what may be causing the noise.
On reassembly the unit now tracks every thing OK except Mike Oldfields Tubular Bells. Very strange.

Rod

Hi Again,
The mystery deepens, Everything is now tracking properly and the reproduction is now better than than ever before.
The scraping noise persists though.
Any Thoughts?
Rod

[kevinkr]

Disk rubbing against tray? Has the platter slipped on the spindle motor shaft? (Is the platter height adjustable - set screw, etc?)

Were the lens to hit the disk there would be a circular scratch on the disk, and the were it to continue for any length of time I would expect the lens to be damaged - not to mention that the focal point is probably a couple of mm away so it would not play in this condition.

[Chivvyp]

Hi, Does it happen with all cds? I've had a similar experience with a few different players but it's only ever been on certain discs.

Another thing to check is that the puck is aligned with the cd hole when the tray is closed. Maybe also check that the puck doesn't have old congelaed grease on it, clean it up, add a spot of grease on the pivot and refit.

I think the mechanism is a cdm 12 on the 48 (from memory). Not sure if they're still available new but you could probably find a donor from an old player off cd. They were fairly common at the time. Don't thnk a newer version can replace it though.

Pete

[rocker65]

Hi,
Thank you both for your suggestions.

I will investigate again in line with your comments.
(I think that later units can be substituted if the right one is used).
Now that I know which and where the relevant screws are, dissassembly and reassembly are becoming a doddle.

As a slight asside, I have read that adding dampening sheets to the casing can improve the sound. Is this a real world finding or just theory?

Rod