This is a bit of a strange thread in some ways. The Marantz SA-10 is a current production model and will definitely be serviced by an Authorized Marantz Service Center. The OP does seem to indicate that the only Marantz Service Center he has contacted seems to only do warranty repairs, which does not seem right, but could be so. If the player is out of warranty, then of course the owner will pay for repairs!!
But this player needs to go to a proper Marantz Service Center to be examined for the described issue. It is a quick 2 minute procedure to determine the laser output level, and if there is a deficiency with that. Of course it could be something else, though not likely.
The traverse assembly (laser assembly) is an in-stock part at Encompass, the Marantz parts house, and only costs $50. But by the time the technician replaces the part and certifies the player to be repaired, the total cost is a fair bit more as repairs take time and time costs money. But the repair should not be overly expensive.