04-12-2015, 09:43 PM
Having checked the spindle motor in question, and two others, independantly of any control circuitry, using my Bench PSU, i find that all 3 rotate in a clockwise direction if +ve is applied to the terminal marked with a red dot and -ve to the other terminal, which seems perfectly logical to me. However all three motors will quite happily turn in an anticlockwise direction if the polarity of the supply is reversed. Current consumption of a few mA @ 5v is the same whichever polarity supply is used, which again, seems logical to me, since spindle motors of this tyes are, AFAIK, the same type as sled motors, but with a spindle ca 25mm long, rather than the about 10-12mm length shafts fitted to sled motors. However, I did measure the spindle of the new spindle motor and found it to be a few mm longer than that of the original, so, although I couldn't see clearly whether the spindle was fouling the disc clamp, I decided to use a motor whose spindle length was the same as that of the original in the hope that it would cure the trouble (it didn't!!). I'm now beginning to wonder if there isn't a fault on what SONY call the 'BD' board -i.e. the control PCB mounted underneath the CD mechanism chassis. Guess I'll have to look for a circuit diagram or service manual for the CDP-EX100 which, hopefully will help me find the answer to the problem!
