Friday, October 22, 2010

Busted DVD player

Wow! Over 1.5 years since last post!

My Sony CX995V DVD jukebox stopped working last week after 4 years of relative reliability.

Some investigation indicated that the CD spindle was not rotating after loading each disk. My first thought was that the spindle motor must be bad. I spent time taking the whole thing apart and removed the spindle motor. I hooked it up to a 5v power supply and it spinned up like a champ. Drat. Now I had to figure out if the motor driver was working. I managed to locate some teeny tiny test points for the spindle drive voltages and solder some wire wrap wire onto them. Sure enough, no voltage across these points. Manually rotating the spindle motor did generate some measurable back EMF, so everything is hooked up properly, just no juice. Turns out this is driven by a Fairchild Semi servo IC designed specifically for CD drives. It has 5 output channels to handle all the various motors in a modern CD player: sled, spindle, focus, etc... Now it seems that all the other functions of the drive are working. I can see the sled move back and forth, the optical assembly was definitely trying to focus. So the IC seems to be mostly functional. Next step: test the inputs to the motor driver to verify that the controller is indeed trying to spin the CD when it is supposed to. My prediction: it is NOT going to be sending a signal to the motor driver IC. If it is just the motor controller chip, there is a SLIGHT chance I could locate a replacement chip and repair the main board. If I have to trace this thing back much further, I will probably run out of leads as to what needs fixing.

No comments: