CDM4/11 platter problem?

[PetrL]

Hallo all,
I have now at home a Philips CD-471 (CDM4/11, TDA1541, cca 1988) to try and possibly buy.

Now the the transport sometimes makes large vibrations side-to-side with random skips here nad there. Other times the same CD slides in in better way and the mechanism is almost silent and of course no skips. I suspect it has something to do with the platter: the conical part has little smaller diameter than has the hole in the CD, so this is not well centered. However the platter is aluminium and doesn't seem too worn out -- maybe the little free play was intended so? On the other hand the plastic clamp seems somehow worn out but I can't imagine this one should center the disc. Does anybody have an idea if this is fixable?

(Sonically it is out of any question (bad) but I planed to pipe the I2S signal from it to the TDA1541A DAC I'm building now or build a new analog stage.)

Petr

[tubenut]

There is a little plastic insert that a ball bearing spins on in the plastic clamp. Slowly the ball digs a pit. If this pit is severe it causes skipping and various read errors. It used to be available from Philips as a spare for peanut money.... If you can not get one use fine grit sandpaper to sand down the little pivot plate so there is no pit anymore. put a little fresh lubricant on the ball as well as the grease ortiginally used will have dried out by now.

Good luck

[tubee]

I have 2 CDM-2's and one CDM4
With the 2's i grinded the litlle pit away with sandpaper, and folded/ glued a thin plate of teflon of 0.2 mm thick on it.(cut a peace from a protective-sheet for ironing) It turns very nice now, with new silicon grease you finish this job perfect.

[PetrL]

Thank you guys! So if I negotiate the price I buy this player. My concern was it vibrates because the laser is close to its end and tries to focus too heftily. But it seemed more to be platter/clamp and now I see it realy happens.

Petr