Sonora motor meter mechanism question

[BillH_NJ]

The motor meter on my Sonora Chippendale console has not worked since I got it and it would be great to get it operational. There is an extra shaft st the back of the motor that apparently should drive it, but the flat arm connected to the meter does not engage with the feed screw. Is the end of the motor meter arm broken or is there a missing piece? Apparently the feed screw should drive the flat slotted bar which then pushes the shaft on the motor meter dial through a geared connection. I am not sure if there are any good photos or drawings of the full mechanism available. Anyone know how this is supposed to look?

Bill