Help with Marantz CD50 skipping tracks

[mgm31]

Hi,

I've bought a Marantz CD50 equiped with a CDM4 mechanism.

The player is skipping some informations ("clic" noise, like if you are moving forward).

This problem is not all time.

I changed the laser pickup only, not the spindle motor : I can't disassemble it and the CDM4 is a special one "composite", not the usual found on others players.
I checked the laser power and laser focus according to the service manual (I don't have a philips test cd, I use a normal CD as the track is only 1Khz sine wave I guess).

Does the spindle motor can be defective ?
Do you experiment same problem and solve it ?

Thanks a lot

[Scorpio(DDMF)!]

I don't think you have a laser or spindle motor related problem.

You can try this:

When the random ff-ing occurs, apply a little bit of pressure on the clamp holder (the big plastic thing that holds the cdm4's clamp) and see if the ff-ing stops...

It seems to be a vibration-related problem; you'll need to inspect the spring clamp for loosing some tension and also the state of the transport suspension springs and shock absorbers...

Also, I believe that the track 1 on the Phillips disc needed to trim the laser current and focus offset is a regular music track (not a 1 KHz one). For that purpose, you can use the first track of a normal pressed cd from your collection; preferably the one which when played makes the laser current the highest (has the highest reflectivity).

Hope it helps,

Cheers!

[mgm31]

Thanks

I tried to clean the clamp and check for correct pressure but this did not help to solve the problem.

I will check again the suspension springs.

The problem is on several tracks, not only the first or second.

I thing that this player will go to the dust bean !!

[Scorpio(DDMF)!]

Originally posted by mgm31
Thanks

I tried to clean the clamp and check for correct pressure but this did not help to solve the problem.

I will check again the suspension springs.

The problem is on several tracks, not only the first or second.

I thing that this player will go to the dust bean !!

You applied the extra pressure onto the clam while the unit was ff-ing and nothing happened?

Before you scrap the unit, maybe you should try to run it without its drawer (you'll need to insert CD's manually) and see if the problem persists. When (and if) it happens, try to steady the transport (plastic part on which the CDM4 is screwed on) with your hand to see what happens...

In any case I would suggest an inspection of the transport springs and shock absorbers...

Don't give up without a fight

Cheers!

[mgm31]

Yes, I tried without the drawer and with extra pressure on the clamp but without success

I found a cheap marantz CD52 MkII (not so good sounding, bitstream conversion)

The mecanism CDM4/19 is the same.

I swaped the entire mecanism (laser + spindle motor) and it's working !!
The spindle motor seems to do less noise.

I will try to but the suspected one on the cd52 to see if the problem is on the spindle motor or not.

[Malefoda]

Originally Posted by mgm31

Thanks

I tried to clean the clamp and check for correct pressure but this did not help to solve the problem.

I will check again the suspension springs.

The problem is on several tracks, not only the first or second.

I thing that this player will go to the dust bean !!

Where is your dust bin ?
Solved ?

[prairiemystic]

I've seen some transports make a mechanical "click" sound when they start to skip or you cue forward (I don't know the CD4M exactly). The worm shaft gear was ratcheting due to lack of grease on the slides. I use molylube to fix that.