Disc Player Spins But Disc Slips


My approximately 8-years-old bluray player had been acting up and recently it stopped working.  It sounded like a mechanical failure, as I could hear something noisely moving inside the machine.  When I opened it up, I discovered that the spindle moter was spinning, but the disc was slipping on the spindle due to the disc not being properly clamped to the spindle.

The short of it is:  A magnet sits on top of the lower spindle platter②, which attracts a floating ferrous upper platter① so that it sandwiches the disc to the lower spindle, and the magnet on my spindle had torn free and was sticking to the upper platter.  I simply super-glued the magnet to the lower platter were it belonged, and that fixed it!  I imagine there are CD and DVD players of similar design which might require the same kind of repair.  Strangely enough, however, I could not find anywhere on the internet my exact problem described by anybody else.

The magnet had detatched from the lower spindle platter② and stuck to the upper platter①.

Fig. 1:  The magnet stuck to the wrong platter①.
Fig. 2:  I glued the magnet back into the correct position②.

This bluray player (LG BD630) is the kind with a loading tray that slides out, then upon closing, the spindle and laser housing swings up to make contact with the disc.  Contact is also made with the free-floating upper platter, lifting it free from its supsension, but attracting it magnetically so that the disc is sandwitched firmly between the platters.  When the loading tray is ejected, the housing swings back down away from the disc tray.  The upper platter is restrained by its housing, causing it to detach from the magnet, freeing the disc to rest in the tray.

The following is a more in-depth description of how to get to the defective mechanism and how I figured it out.

Safety first!  Your disc player is an electrical device which can cause physical harm or even death if handled improperly.  The device should remain unplugged the entire time you're working on it, excepting when you absolutely need to see it operate with the cover off, but even then it should be only briefly and you should not reach inside the machine.

Even while the machine is unplugged, take care to not touch anything you don't need to fiddle with, as capacitors can hold an electrical charge after being disconnected from a power source.  I once gave myself a nasty little shock handling a camera's flash capacitor, and I heard of a guy who got knocked unconcious when he tried to pick up an exposed tube television that had been sitting in a junkyard for several years.

As I already mentioned I couldn't find a solution to or even a description of my unique issue on the internet.  I'm not particularly knowledgeable about home electronics, and frustratingly I couldn't find any schematics to help me identify the parts so that I could look them up by name.  (Remember when stereos used to come with full repair schematics?)  I apologize if I use some incorrect part names.

After making sure the machine is unplugged, remove the cover③ and, if you have a typical recent model, you'll likely see that 33% of the case is space wasted to make the machine as wide as your old VCR.  The rest is the optical drive assembly④ and circuit boards⑤ that handle the software.

Before I could focus on a solution, I had to spend a great deal of time figuring out how to pull apart the optical drive assembly without breaking it (it has some snap-into-place assembly) and learning how the tray mechanism works so that I could put it back together correctly when I was done.

Inside a typical sliding-tray disc player.

Fig. 3:  Initial view of the interior.
Fig. 4:  The optical drive chassis, upside-down.

For convenience, you'll need to eject the disc tray⑥ then unplug the machine while the tray is still open.  If your machine is like mine with a front panel on the tray, you'll likely need to remove the tray's font panel in order to pry off the player's font panel⑦ (on my machine there are multiple catches on all four sides of the front panel), in order to remove the optical drive④.

Remove any screws⑧ holding the drive assembly in place, then detach cables connecting the drive assembly to the circuit board, if they are detachable (my machine has convenient pull tabs⑨).  You should now be able to remove the optical drive assembly.

My drive assembly had the drive housing attached to the chassis via snap-in-place hinges.  With a flat-head screwdriver, I carefully pried open a snap-hinge wide enough to push the hinge out (not pictured).  In the center of the drive chassis⑩ is the upper spindle platter.  (In the picture, the platter is popped out so that I could fiddle with it, and there's electrical tape which I had added unnecessarily, thinking it would help, before I had figured out exactly what was wrong.)  You can see here the out-of-place magnet on the platter.

The issue was clearly that the disc wasn't being properly sandwiched between the platters, but I initially didn't realize this was accomplished with a magnet, and incorrectly thought that it was done by pressing the disc firmly against the upper platter.  There were signs of material having torn loose from the spindle platters (figure 1), and you can even see a point on the inner rim which looks like it's been mashed down, yet there was no debris inside the machine, so I chalked it up to slow, incremental wear.  My first attempted fix was to apply some electrical tape to the upper spindle platter (figure 4), thinking it would grip better and be less abrasive than bare plastic.  This didn't work of course.

Fixes that don't work!

Fig. 5:  Don't try padding the upper platter!
Fig. 6:  Don't try padding the slide pegs!

I then thought the clamp somehow wasn't lifting high enough to sandwich the disc, so I put a trimmed-down strip of adhesive-backed rubber seal on the upper spindle platter (figure 5) to take up the gap.  This seemed to work, but the tray and disc dragged across the bulge of the rubber seal every time the tray opened/closed, and when a disc played it made a horribly loud noise that made me worry that vibrations were going to shatter the disc, so I took the machine apart yet again and took off the rubber seal.

I thought maybe the pegs that lift the clamp when another part slides them had worn down just enough hair widths to not make the disc sandwich properly, so I wrapped a strip of duct tape around the two pegs (figure 6).  This did not work at all.

Finally, I was staring at pictures of DVD spindle motors on-line when I realized that mine looked very different.  That was when I realized that the magnet was misplaced, then I super-glued it where it belonged.

To put the drive assembly back together, make sure the pegs that slide through the grooves under the tray are lined up correctly, place the pegs on the end of the laser housing into the piece that slides them⑪, then snap the hinges back into place.  (If you accidentally close the tray while you still need it open, you will have to reach in with a thin screwdriver and manually engage the peg slider⑪.  Don't force the tray open by pulling it, as the peg slider may be locked behind a 90°-bent groove which must be cleared before the tray can move.)  Screw the drive assembly back into place, reattach the internal cables, snap the player's front panel back on, snap the tray's front panel back on, and reattach the cover.

This no-replacement, no-technician repair saved me $100-200 as I was about ready to give up and replace the machine with a new, not-crappy region-free player, and I'm really proud of what I figured out and accomplished on my own.  I can't help but wonder if the anti-right-to-repair lobby would take objection to what I just did.

One last word about video disc players:  If you travel internationally, practice a foreign language, or just want to expand your video-watching horizons, do yourself a favor and get a region-free DVD/bluray player.  If you're lucky you can just look up a button code for your current player on VideoHelp.com, or you can buy a machine that's already been unlocked.  I have bought good region-free players from CodeFreeDVD.com and Bombay Electronics.  There are also several models available on Amazon.  To watch movies on a Windows PC, I recommend AnyDVD which unlocks your player on a disc-by-disc basis and also removes user operation prohibition so that you can actually skip advertisments and stupid animated menu transitions.