Mistracking problems after new disc load

[jeff mai]

I've picked up an old Yamaha CD-3 with PCM53 to play with. It's exhibiting a strange problem - it reads the TOC fine, but then struggles to lock on to the data when you play the disc. It may mute or simply skip (like pressing the FF) into the first minute or so and then lock on. After that, no skipping. If you jump back to the beginning of the disc it will even play what had previously troubled it with no problems. As soon as you open and close the tray, the problem comes back even if it's the same disc.

Seems strange because once locked on it tracks well, it just takes a while to stabilize every time the tray is opened. I can't see any mechanical problems with the mechanism. What do you guys think?

[Netlist]

Jeff,
This is what I found in my database. It's from a CD2 but could be of value for the CD3 as well:
Symptom:
Track jumping mainly at the beginning

Solution:
Check on thrust bearing if the board has not been worn in. Check Disk motor for bearing damage.

I don't know the player so don't ask for more details.

/Hugo

[jeff mai]

Originally posted by Netlist
Check on thrust bearing if the board has not been worn in. Check Disk motor for bearing damage.

Thanks for the info Hugo.

I was playing it with the cover off last night and discovered it had to do with the disc clamping mechanism. When it was acting up, pressing on the disc clamp cures the problem. So I guess sometimes it doesn't clamp the disc properly. It could be caused by one of the problems you mention above. I'll check it out.