Hi !
While wrangling a real-cranky FBX file, I came across the modern successor to the viewer app in Autodesk's classic FBX Toolbox.
https://www.autodesk.com/products/fbx/fbx-review
This viewer is free for download following free registration. It also opens a bunch of other 3D formats. It is strictly a viewer, will not save or export.
From the web-page:
Open files in a variety of common 3D formats to help improve the speed of asset review: .zip, .abc* .fbx, .3ds, .obj, .dxf, .dae, .bvh, .htr, .trc, .asf, .amc, .c3d, .aoa, .mcd.
*Compatible only on desktop versions of FBX Review.