[ynneb]

First comment: Nearly every site on the web calls the motor windings A+, A-, B+,B- You should include that to reduce confusion.

This is only a drawing of the power supply. There is no reference to steppers or drivers, I am not sure what you mean ?

Second Comment: My power supply has a huge capacitor, a diode bridge, and a large hollow resistor across the top of the capacitor. Is is optional and why?

The resistor that you are refering to is not shown in my drawing, is called a bleed resistor. Its function is to discharge the capacitor when the power supply is turned off. If your power supply is turned off, the capacitor can still hold current and can cause a problem when wireing to the drives. Similar to hot swapping wires. You can make your power supply swich trun on/off both the AC and DC sides at the same time, instead of using a resistor. I guess as good practice it is better to have the resistor, but it is not essentail in the running of the power supply.

[garagefela]

In reponse to the bleed resistor, I had asked a question about this a while ago and got some good replies.
In short it can either be wired directly onto the capacitors so it is online whenever the power supply is on and bleeding down when power supply is off OR wired to the off position of the power switch, the resistor wont actually be online when power supply is on but will bleed down when the switch is thrown to the off position.

I suppose the danger doing it the switch way is that you can pull the power lead to the power supply without flicking the switch to the off position and still have the capacitors left in a charged state. ZAP ZAP.

Cheers all M