Here was my fix. My son has a coby dvd player--"wrong disc" message. cleaned the lens, same error message. had nothing to lose. took it apart. thought of corrosion on jumper switches. pulled all of them off and put them on two or three times. Had this problem with a nikon flash once. This fixed it... works like a champ.
You will need a small screw driver, check to see the type of screw heads, to detach the bottom and expose the circuit board; and a pair of needle nose pliers to remove and reinsert the jumper switches. Make sure no electricity is running through the unit. good luck, hope this helps.
Kirt
July 2008