What causes the occasional crunch from the CD drive?

[Official Ninja]

Last night I was playing a game of Carmen Sandiego and when I got to the 1st VILE henchman the CD unit went to load the animation and **CRUNCH** it made that famous crunching, skipping noise. Otherwise it loaded and played just fine. Yesterday I was playing Shanghai III and when the background audio track went to repeat...**Crunch** and then it played fine. Plus every repeat after that seeked with hardly any noise.

Now I've owned more than one of these CD units since the launch of the TG-CD. All of them have made this noise. Our friends unit made the noise....I noticed it seems to happen about once per use. I remember once in the early 90s playing Ys and the CD drive make a loud crack noise like the laser just took off during a seek and slammed into its limit with no stop switch. Me and my brother looked at each other and we had that *ouch** look, but it seemed to work fine after.

What is the cause of it? Is it the gears actually skipping? Seems like some times when the motor goes to rapid the laser sometimes it just skips? If I was to guess I would say it was skipping between the gear on the lasers screw and the middle gear. I guess that because the gear on the screw can move back a bit under pressure.

Anyone ever narrow this down?

[kid_rondeau]

Ninj,
I've often wondered the same thing! It happens to all three of my TG-CD's!

[BlackandBlue]

The assembly that goes on the worm gear is basically a plastic arm with a metal tab on top to keep it from breaking, but at the same time, under force (eg hitting the end of the track without the switch stopping it first) will allow the worm gear to keep spinning and not break the assembly.  I'm guessing that you just seeked to the edge of the disc quickly and it hit that limit where it kept trying to go.