You can download the from Haag-Streit’s document archive (search for “BM 900 instructions for use”).

Use a soft optical dust brush to clean the exposed surfaces of the eyepieces and objective lens.

If the device fails to operate correctly, follow these diagnostic steps: BM 900 - Slit lamps - Haag-Streit UK

. To the uninitiated, it was a list of diagrams and part numbers; to Aris, it was a map of a tiny, mechanical universe. The Inner Workings