This unit was in a sad state of affairs, covered in dust, pet dander and hair, human presumably. It appears to have been sitting for years. When the hardware is in this condition, just start tearing it down, don't even bother with trying to spool it up.
I enjoy restoring hardware, the worse the better. In this case, underneath all the debris was a MAC1700 chassis in near perfect condition. And most of the bits and pieces are still available. A complete tear-down was in order. The way I proceeded here, first > power supply, second > output section and third > preamp then spool it up on the Variac after all resistance checks evidence nothing's shorted to the chassis (say, for example, the output transistors shorting to the heat sinks).
MAC1700_3.jpg