Rostock max - stuck on power supply

[jeffhuber]

On page 27 of the docs it mentions

Start by locating six long yellow and black wires in the power supply.... Clip the yellow and black wires you've chosen..

Then on page 29, it says:

now take the four long black wires from the bundle... do the same for the four long yellow wires.

I found one bundle of 3 black and 3 yellow together - so I cut those. There is also a bundle of 2 black and 2 yellow (but those seems to be reserved for the RAMBo?)

So I just have 3 black and 3 yellow, but it wants me to bring 4 together...

Does it matter which black and which yellow I use?

Thanks for the help. I can post pics if needed.

Jeff

[Captain Starfish]

Try it, measure the voltage across the bundled yellows and blacks when everything's fired up. If it drops much below 11.5V I'd be adding more yellows and blacks in.

[Jimustanguitar]

On most power supplies, (definitely the one in your kit) all of the blacks and yellows go to the same place. There is no difference, so just pick whichever bundle has the closest quantity to what you're looking for.

[jeffhuber]

I don't own a voltage meter yet =)

But that's really good to know that I'm basically stacking wires to add voltage and that the colors reflect the voltage.

Is that right?

Thanks Starfish and Jim!

[guanu]

not to add voltage, all yellow wires are 12v.. the reason you use multiple in one connector is because of the current draw, more wires can handle it easier... but yes, on the computer power supplies that came with your machine, the colors represent the voltage

Guanu

[jeffhuber]

Thanks Guanu!! =)

[nitewatchman]

Very close, you are stacking wires to add ampacity. The voltage is the same on all the yellow wires and with no load it should be slightly higher than 12VDC. If you place a load on the wires however that is a higher or near than the capacity of the wires there will be a corresponding voltage drop which raises the current proportionally but reduces the delivered power. Think of running a power tool (circular saw) on the end of a long light weight extension cord, results can be not so gratifying. One fix for this is to just use a larger extension cord which reduces the voltage drop allowing more power to reach the tool.

For the printer, gathering 3 or 4 yellow and black wires is equivalent to making the extension cord larger. It increases the current carrying capacity of the wiring to the RAMBO and the power available to the heated bed. You may even safely mix yellow from multiple connectors if you require more. These usually always tie to the same buss in the PS and if there is a problem created the crowbar circuit in the PS will simply shut it down.

Remember that this also applies to the wiring from the RAMBO to the heated bed. You will help your case by running multiple red and black wires or a single larger gauge wire. I use a #14 AWG wire which is as large as easily fits the RAMBO connector. You could also use two #16's or three #18's. Just like in Ghostbusters however, "Don't cross the streams". Make use you keep all red's with reds and blacks with blacks and yellows with yellows.

By the way, you really need a multi-meter. Even a cheap $12 Radio Shack meter is excellent. I carry one in my travel bag all the time and it has over 600,000 miles on it now. Works well and if TSA wants it no harm no foul.

nitewatchman

[Captain Starfish]

Hint: If you don't already have a meter, do yourself a favour and throw thirty bucks at one that comes with a thermocouple and ºC reading.

[nitewatchman]

Second the motion.