Marantz CD-67mkII starting difficulties

I have searched the internet but couldn't find :( a solution for my problem. I own a Marantz CD-67mkII and was very pleased :) with it. Recently it was starting to refuse to play my CD's :mad:. If you put a CD in the drawer and close it, it will display "dISC". Sometimes it does, sometimes it does not and just plays the disc. After removing the hood I am able to help the disc starting by turning it a little by hand. In such way it is possible to get the disc starting. Also in service mode it always starts spinning the disc. In normal mode it often refuses to start spinning the disc, resulting in a no disc ("dISC") response in the display.

After reading several posts on the internet I decided to buy a new laser and motor unit. Originaly a CDM12.1 Philips unit was mounted. I replaced it with it's successor the VAM1202 unit. Unfortunately this doesn't solve my problem :rolleyes:.

Does anyone know what probably is the cause of this malfunction?

I also read a lot about improving this player, so once it works again I also have planned to do some modifications. Does somebody have suggestions what will be worthwhile to do.

I am aware it is a rather old player, but as I see how much is posted about this player I think it is still actual.

Thanks in advance for any helpful info.