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Naim CDI mechanism?

Dowser

Dowser

Learning to bodge again..
What mechanism is used in the Naim CDI player? Is it still available? And any common problems that sees it spin a disc for a second but not read the toc?

Thanks!
Richard
 
Hi Richard.

The Naim CDI originally used either Philips CDM4/22 or CDM4/27 transport mechanism and they are no longer made.

The common problem is that the rubber(s) on the puck flattens, doesn't grip properly and allows the disc to slip when it goes to read the TOC.

Quick way is to roll two small beads of bluetack and place them on the underside of the puck to give a bit more grip.
Try that and if it's OK, then problem is puck slip - replace, repair or read this from Graham (Laverda) .....

http://www.pinkfishmedia.net/forum/showthread.php?t=32028&highlight=dr+laverda's

If the laser is defective then contact Les W (Avondale Audio) who may be able to help (as long as the motor mech is OK).

Regards Dave.
 
Wilky said:
Charles.

That's a bit steep for a puck!
;)

Dave.
Click to expand...

Yes but you get the Cdi included! My buyer compared it to hs Wadia 850 and decided to keep the Wadia. Shame as I had agreed to buy it!

He offered me my CDi back but I am off Naim. Good buy for someone.

Charles
 
Oops - I won it, €201...how do I explain that to my wife? :)

How much does a CD5 (or is it the CD5i) puck cost new?

Cheers, Richard
 
Thanks - ordered a top hat original, plus a CD5 series puck. I've also read that the electrolytics on the servo board can give problems - anyone know what values I need?

Thanks, Richard
 
Not sure if all CDI's use the Philips servo board? Photo I've seen uses one, and diagram for a CD850 shows 3 electrolytics on servo board; 2 33uF's on voltage pins of servo and radial motor chips, plus a 47uF on the base of the laser drive transistor.

Cheers, Richard
 
I had exactly the same problem with my CD5 - a new puck fixed it straight away. I was steeling myself for a servicing bill so it was a handy fix.
 
I'm disappointed;
1.) it has a later CDM9 Pro mechanism
2.) someone decided using a screwdriver to try and prise the spindle motor platter off was a good idea - the platter is now warped, and it also appears the whole motor is sitting at an angle (may have been original reason for someone trying to prise it off?).

Disc half spins once, then quickly gives up with an ERR.

Damn! I recall reading somewhere that cdm9 pro lasers can be swapped out from another cdm mech...but that you'd better hope the motor is OK...

Does anyone have any experience of getting the platter off the spin motor spindle?

Unless I can find a spare 2nd hand CDM9 Pro (unlikely I guess), my only option is to try and fit a later Philips mechanism/servo board combination. Anyone with any experience of such surgery? The CDM9 Pro servo board is a Naim one, and I see no oscillator on it, so I assume main clock comes from main board. So, it should be as easy as sorting power requirements and matching input control signals and output digital signals...or am I being naive? :)

On the good news front, it has a double crown TDA1541 - I thought the CDI's only came with single crowns? Maybe I break it for spares!

Photos;
Internals - you can just see double crown: http://richard-dowsett.fotopic.net/p40227959.html

Got scared when I saw these scratch marks: http://richard-dowsett.fotopic.net/p40227961.html

Confirmed fubar: http://richard-dowsett.fotopic.net/p40227960.html

Ho-hum...

Thanks, Richard
 
I managed to get the old platter off - trick is to lift the motor spindle off it's bearing base with a couple of screwdrivers under each side of the platter (has about .5mm upward play). Then a light tap on the end of the actual spindle breaks the (what looks like) superglue bond between the alu platter and the motor spindle.

I was suprised before that the motor bearings felt OK after the abuse it must have suffered when someone warped the platter, but you can see from below photo that the bearing is an over engineered lump of brass, it's fine! Also, the platter itself is thing aluminium; it wouldn't take much force to bend it (although the scrathes on the CDM9 chassis tell a different story!).

As the motor and shaft seem fine, I can only assume someone thought the spin motor was faulty and was trying to remove the platter to get at the screws. I'm guessing that means there a fault elsewhere; either laser or servo board problem - does anyone know if the Naim servo board used in the CDI with CDM9 mech also suffered from electrolytic problems? There's a couple on there, they look fine but...

So, what now - old platter is junk; I am unlikely to be able to get it true again. I can't get a new one manufactured, as it has the magnet in the middle of it. I wonder if any other Philips mechs use a similar platter? I can see some begging emails to Philips coming on!

Otherwise, checking on DIY Audio, there's a whole host of other mechs I should be able to mount - CDM4/11 also has a metal spindle with magnet that I could fit to get it running (motor is better than stock, but not as good as the 9 Pro item I guess) while I search a replacement CDM4 or 9 PRO mech.

CDM4/11 is used in a wide range of old Philips machines - tracking a few on eBay now. It'll come with the servo board that should allow direct connection to the CDI.

Photo of the spindle motor removed; http://richard-dowsett.fotopic.net/p40254164.html

Richard
 
Richard, if you remove the mech and send it along, I may be able to help

Cheers, Les
 
Les is a star, and will be sending me the bits to renovate my CDM9 Pro next week!

Richard
 
I now have a working CDI, and very nice it sounds too :)

Many thanks to Les - he offered to attempt repair of the mech if I returned it to him. Having already spent €210 on a broken CDI, I wanted to keep costs down - he gave me advice on best way of approaching it, having more interest in seeing the player revived than making money, and provided a tested CDM9/44 mech to use as a base at a good price.

Photos below; quite a simple task; took the platter off the old mech, drilled out to correct size and remounted on the CDM9 Pro spindle motor (taking great care to ensure height was correct). Then transferred laser and fitted everything back together.

Sound is good in the mid, bringing out stuff I never heard before and giving a great space around sounds - of course it's foot-tap'ability is impeccable. Still have reservations at high frequencies, but it has only been on for a few hours so far. Very happy - not quite the bargain I had hoped for, but under £200 for a CDI with a known good laser is still not bad.

Just need a re-run of Pink Fleas now Martin :)

Now I need to fix the CDP-X707ES and sell it - sound is detailled but uninvolving, and such is the internal engineering that I can't bring myself to modify it!

Richard

Photos;
CDM9 Pro and CDM9/44 side by side;

http://richard-dowsett.fotopic.net/p40649607.html

CDM9/44 platter off (used 2 knives, "pop" and caught it on it's way down :))

http://richard-dowsett.fotopic.net/p40649606.html

Spacers to ensure correct platter height (measured off CDM9/44);

http://richard-dowsett.fotopic.net/p40649604.html

Platter mounted on CDM9 Pro (drop of superglue);

http://richard-dowsett.fotopic.net/p40649602.html

New platter and laser mounted in CDM9 Pro mech;

http://richard-dowsett.fotopic.net/p40649597.html
http://richard-dowsett.fotopic.net/p40649609.html

With light shield in place;
http://richard-dowsett.fotopic.net/p40649611.html
 
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