Marantz 4000 CD Tray Door Won't Stay Closed

I was told by people intimately familiar w this player to check the tray switch but need to find it and it is nowhere to be found in service manual.
Its a small plastic lever which moves back and forth , according to tray movement. Its usually a 5 pin switch located underneath the tray mechanism. Put a drop of IP alcohol , switch cleaning oil , or even cycle oil (If you have nothing ready in hand ) on the switch. Careful with lens, avoid spillage or sprays. If u want I can post pic of PC DVD drive to get an idea . Usually , all these drives are based on Philips or Pioneer mechanism design