Sir +Turbo . . . . .
Well then, do you minimally have . . . . . or have access to . . . . .a DVM, to be able to test that one diode and see if it is being dead shorted . . . . or being open circuit.
As well as your photo can show, I could conceive of that being used as a directional device function if you had one more like diode to then make a total of 4 of them.
Minimally, it might be used as back EMF inductive damping on that units brush type motor.
Otherwise I am only seeing a green disc ceramic capacitor, one other like diode and 4 wires visible . . .plus the drive motor.
If you want to try something.
And duly considering that diodebeing shown to us is to be rated at a maximin current carrying capability of 1 amp and at as low of a voltage rating as the bean counters mandated on enginering.
Find yourself a common as dirt . . . .1N4007 diode and use it in the position that you pulled that one from.
You DO need to obey installation protool in having the BLUE banded lead of that black bead diode body's wire lead, as being in agreement of a cylindrical black body with a silver band on one end, as will be on the new 1N4007 diode.
Then only leave power on for 5 seconds of your initial trial run to confirm motor action. Works ? . . then go for it.
Ask us if you need info on using a DVM in testing the old diode.
As a final step, you might collect all of the spun aside goober-luber and then re apply to the two helix gears mating / meshing surfaces.
Thassssssit . . . .
73's de Edd
.....