I bought 2 old Calrec PPM drivers on ebay some time ago. No documentation was included. I figured out the inputs/power/outputs & fired them up into a pair of Sifam PPMs.

The good news: They came up exactly right with +4dBu = PPM 4 and the top end of the scale was right on.
The bad news: The bottom half of the scale was far off with errors getting larger at the lower end. They both have identical errors.

They have several adjustments & I guess I could hack around and figure out what they all do but it would be so much more civilized if I could locate an alignment procedure or at least a schematic.

Can anyone here help?

Thanks