Sorting out connections

How to connect basic parts to a Ramps bd is easy!!!!!!!!!
But I have complicated matters by using 2 extruders.
Now, I need to connect a fan extender and use some additional I/O for LEDs etc.
When does +5V not = +5V??????
When it is on a Ramps schematic.
5v pins on the servo I/O appears to only go to the 5V pin next to the PS ON pin.
It is not connected to any other 5v designation on the schematic.
That 5v pin apparently is an INPUT pin for servo use.
Where would one get 5v for that pin?
I have searched for hours and not found any reference to that.
And what is Vcc? It is not 5V and it is not connected to ANY 5v designation on the bd.
So where does Vcc and THIS +5v come from??
Is there anyone who can sort this out for me??

Quote
ruggb
When does +5V not = +5V??????
When it is on a Ramps schematic.
5v pins on the servo I/O appears to only go to the 5V pin next to the PS ON pin.
It is not connected to any other 5v designation on the schematic.
That 5v pin apparently is an INPUT pin for servo use.
Where would one get 5v for that pin?

You are correct that the 5V pin next to PS_ON is an input for supplying power to the servo connectors (and only those connectors). If your servo needs are very low, you can jumper that pin with the other pin in that header, VCC. This will use the Arduino's 5V regulator as the 5V power source. Note however that most people find that the Arduino's regulator can't supply sufficient power and experience erratic servo movements or none at all. The recommended solution is to use a separate 5V regulator or power source.

If you use an ATX power supply, just use one of the red wires from the supply. Or use a dual voltage power supply that has 5V and 12V.

If you just have a 12V power supply, you can use a LM7805 as a simple solution. Some people just shove it in one of the power connectors with a wire from the output heading up to the 5V pin or you can make a more elegant circuit. It's not very efficient; a more efficient solution is a cheap buck-boost regulator (search ebay or Amazon for "LM2596" for examples)

thx - My other point of confusion is that whoever created the pin output diagram changed Vcc to 5V everywhere. I went back and looked at the schematic and the only 5V is the servo 5V.

Maybe u can answer this part of my problem - fan extender bd apparently is only 2x N channel MOSFETs in a package so they need only a ground, 12v, and input signal. I put this
#undef FAN_PIN
#define FAN_PIN 11
into my Marlin 1.0.3 dev configuration.h but it does not work. What am I missing?
thx

Edited 1 time(s). Last edit at 05/15/2015 03:17PM by ruggb.

got it, thx