Sled motor problem

rcdee

Hi Kaosun

I have been replaced total  5 capacitor and add a grease to the laser head mechanical parts, now my player can read the CD, but the sled motor only can move to the outside , when i want to play back side the motor can't move,
now the head position can't back to the start point, how can i fix this problem?

When i add the grease to the gears and use the tools put the gear moving , i can feel the gear have friction(Need quite large force to put)  can you please advise how can i fix this movement problem.

Thank you so much.
Mr Lau

kaosun

Sled motor failure can cause you single direction rotating issue. The case I encountered is in D303. The sled motor shorts circuit when it rotates CW but CCW is fine. You can pull the gear on the sled motor's shaft 3-4mm out to release the gear connection to test whether the sled motor can perform CW and CCW rotation. If it can, you should disassemble the middle gear for thorough grease lubrication. If it still rotates single direction, you'll have to spend some more time on:

1: Be sure the MPC1715 pin41 has receive FF/REW single. Usually, the pin41 is 1.7V. If it receives voltage lower than 1.7V, it rotates CW(the less voltage the faster rotates); if it receives voltage greater than 1.7V, it rotates CCW(the more voltage the faster rotates).
The voltage range of pin41 could be 0.5V-2.5V, 1.7V is the middle point. If the MPC1715 received the rotates signal but the sled motor doesn't rotate (without gear connection), check whether the sled motor has internal issue. Or replace MPC1715 for try.

2: The pin41 of MPC1715 is derived from pin14 of servo CXA1272. If you press REW but pin14 doesn't have any corresponding voltage change, check the feedback resistor R522. If the sled motor rotates not powerful enough, increase R522 to 150K or higher but less than 220K.

3: Usually there're 3 capacitors in 555 need to be replaced. Two in earphone amp, one in power supply. I'm wondering why you replaced 5?

bru87tr

Not sure if similar problem. But I have a D-9 where the motor wanted to move but would not. It was hard to turn. The grease looked like new and not hardened. Everything looked good.

I squirted a drop of CRC electronic lube down the spindle side of the motor. Kept moving it both ways and finally it works like new. I tried working it without lube, but it just wouldn't move. The lube in the motor fixed the trick!