OK, here's the real way to remove the chassis from the bottom pan after the top cover is off.
If the unit is an earlier one, the green grouind wire I mentioned above will be there and must be disconnected. Later units have the ground wire attached to the terminal strip underneath.
Since the speed change cam is mounted on the motor mount which stays with the bottom pan, the speed change lever must be disconnected which is done by slightly raising the cam and pulling the lever off from the bottom.
The four clips holding the chassis onto the bottom pan are not like cotter keys or anything like that at all. They are "E" clips or are sometimes called "C" clips. So much for my memory.

Remove these and the chassis will lift up.
As you lift the chassis, on earlier units, there are three spade plugs which must be disconnected from the terminal strip. Note where they connect. I believe later units have a keyed plug inline which just needs to be unplugged instead of the three separate spades.
The chassis should now be free from the bottom pan.
Gary, yours looks like a later unit going by the cue lever but who knows exactly when BIC made the changes. In the PM, I mentioned I thought the pitch change belts are round but the long one is toothed. A flat one tight enough may work OK.
Also, my last instruction about being careful of the strobe mirror/adjustment knob assemblies is nuts too. That is during the top removal which you, obviously have already done.
Doug