Make Sure the Problem is the Player

• Most CD players have been through quite a bit. And so have most CDs; people stack them, throw them around, store them outside their cases. If your CDs are skipping, check to see how badly they're scratched. CDs can withstand a pretty good beating, but each has its breaking point.
  
  Also, check the connections from the main unit to the speakers. Many CD stereos are old, and their speaker cables wear down with time.
  
  

Clean the Lens

• CD lens cleaners are becoming harder to find as the technology grows obsolete, but they're still out there if you look hard enough. Lens cleaners are compact discs with a tiny brush on one end. The brush passes over the lens to remove dust, dirt or smudges.
  
  

It's Probably the Read Head

• The most common problem with old CD players is that they can't seem to "find" the CD, even if it is clean and unscratched. You put the disc in, and nothing happens. If this happens all the time, your read head is probably out of alignment.
  
  

Fixing the Read Head

• If the problem is your read head, and if you're willing to risk voiding your warranty, open your CD player's casing. This is easy on standalone CD players, trickier in boom boxes, and very difficult in small CD players.
  
  Once you've opened the case, remember which screws went where, then look for a small circuit board near the lens. Near this board should be a small square part with a plastic disc on top, and a screw for a flat-head screwdriver. Mark the position of the screw, turn it ever so slightly, and through trial and error, see if your CD player's performance improves.