sharp dx-612 manual

They had a lot of shorted spindle motors on those...

Mark Z.

On 30 Mar 2012 19:06:37 GMT, snipped-for-privacy@notvalid.it put finger to keyboard and composed:

- Franc Zabkar

many thanks!! I was sure I had checked there, but obviously I wa wrong :-)

Frank IZ8DWF

this one looks like it's still spinning... It just doesn't play most of the discs.

Frank

Many times the motor is still the culprit, and the disc is having trouble getting up to speed.

Try testing the motor with an analog VOM on Rx1 ohms range. Slowly rotate the motor. The resistance will vary as the motor is turned, but should be around 10 ohms on each 1/2 of it's rotation. Sometimes one or both halves will be shorted or partially shorted. It is often possible to clear the short.

You can spray cleaner/lubricant into the slits at the bottom of the motor, aimed at the brushes, while turning the motor by hand. Use compressed air to blow out debris and excess lubricant. Repeat til short cleared. Very effective, fixed lots of cd motors this way over the years, only ever had one re-do, and that one was in commercial use.

You can even connect a variable dc supply to the motor, run it at a given speed, spray the cleaner at the brushes and really notice the motor "taking off" when the short clears. Even without cleaner, if you run the motor at a pretty high speed, the carbon will likely burn away at some point.The brushes pick up the carbon from sparking, which shorts out eventually. I_think_ a silicon based lubricant will prevent future carbonization.

Mark Z.