If you SA-10 is anything like my SA-15S2b, then look at the rear of the unit. Running along the top should be some screws that secure the top lip to the unit’s back frame.
After undoing those screws, there should be (if Marantz form follows function ) two relief areas that raise out from the lip of the top trim.
Using some thick cardboard or something similar placed flat against the back of the unit with it abutting the top trim, place a flat head screwdriver up into the relief and gently turn it. Then do it to the other one. It may take a couple of tries but notice the top lid will not move much as it take just a little movement to free the top from where it securely mounts to the top front of the unit. (The cardboard is used to prevent any damage or nicks to the back of the unit).
Now just pull backwards and slightly upwards on the top after it frees itself from the front of the unit and it should come right off. There may be some top frame guides that run along both top sides that help secure the top lid. They just act as guides and help to keep the lid on tight. You should have no trouble locating your Herbie’s disc damper.
All the best,
Nonoise