Tom. If your 2620 is the same as my 2630 then you have some choices.
If you use Workbench 1.3 hold down both mouse buttons while booting the
machine. A menu should appear.
If you are use Workbench 2.04+ hold down the right mouse button while
booting and select the processor you want.
I also tried connecting all the jumpers on the board. One of them will
give the processor choice menu every time you boot (without touching the
mouse)
David Kay
Flying in from Montreal.