Thank you, Yves - I appreciate your information and agree that the unit is very nice tool (although very heavy!). Fortunately, this unit appears to still work internally, as the problem of leveling/output seems isolated to the periphery of the system, not the internals.
I do not directly see the need to separate the assemblies, provided that I can physically move the upper unit front panel forward slightly to gain access (working inside the gap between the bottom of the relocated upper unit, and the fixed lower unit, it seems access to the mounting nut for the connector should be accessible.
Do you remember what path you followed to reach the connector nut behind the upper unit front panel?
Thank you again!
