... also, you should check that there is no chafing to the 4-wire power harness inside the player. If there is, re-insulate any cable chafed this way. I routinely (now) put a cable tidy around these 4 and pull them over the drive sled to lie on top of the back of the drives.

Have you tried your player in his installation? Is there a difference? Have you got a Mk2 or a Riocar? What has he got, a Mk 2 or Riocar?