Turns out the 4.5VDC 300mA wall adapter puts out 7.75, 7.85 and 7.95VDC (I found a 3 screwdriver).

The motor is a Leshi Motor 3805-30205, 3.6V, 030925/B.

This screwdriver has no controller circuit, , just a switch, 2 batteries and power jack. It runs with wall adapter connected with these old 7yr+ batteries.

Voltage at motor is 2.65V using wall adapter and 2 batteries still connected, gradually dropping. Does the same using the batteries only.

(still testing)

Robert