I recently acquired a Dranetz 606 Power Line Disturbance Analyzer. Dranetz was kind enough to fax me a manual, and I've scanned it and reproduced it as a PDF:

User's Guide: Dranetz Power Line Disturbance Analyzers
(Series 606-1, Series 606-3, Series 616 (A, B & C), Series 606-PA-600X).