Power Supply Wiring Confirmation

I purchased the following PSU (Manual), and I wanted to double check I am wiring correctly.

The Alpine PSU (in the Mendel90 manual) has 36 wires but the PSU above has a few more. I think I am supposed to use the following wires from my PSU:

(24 wires) 4.1 Motherboard 20+4Pin Connector (P1)
(4 wires) 4.2 CPU 4+4Pin Connector (P2, P3)
(4 wires) 4.5 Peripheral 4-Pin Connector
(4 wires) 4.6 Floppy Connector

Is this correct?

Also what should I do with the other unused wires?

Thanks in advance.

The main difference with that PSU is it has a split 12V rail of 18A each. That is enough to run the machine so you could just use 12V1 and leave 12V2 unconnected. You might get a bit more voltage if you split the load between the rails. To do that instead of connecting the red bed wire to the Melzi, connect it to 12V2.

The other likely difference with that more expensive PSU is that the wires will be thicker. That means you won't be able to get them all in the Melzi terminals, so just use as many as will fit and cut the rest short and insulate them.

The thicker wires might also mean the heat shrink supplied does not fit so you might needs to use some insulation tape or get thicker heatshrink.

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[www.hydraraptor.blogspot.com]

By reading this I am assuming that you can't just connect together the 12v1 and 12v2 lines?

Do the PSU's you supply in the kit not have the 12v2 rail and just a higher rating on the 12v1?

And your suggestion with the heated bed is to connect the positive lead of the headed bed to the 12v2 wires, but still ground the heated bed through the melzi correct?

Thanks!

Edited 1 time(s). Last edit at 07/31/2013 02:23AM by goopyplastic.

The PSU in the kit only has one 12V rail.

You might be able to connect the 12V rails together or you might not. It depends if the PSU has two independent 12V supplies or just one with two independent current sensors. The reason they are split it in the PC is to limit the maximum current in the wires for safety reasons. The cheapest way to achieve that is to just use two current sensors. You could test that with a multimeter. If the two 12V outputs are connected via a very low resistance then it will be fine to connect them together. If there is more than a fraction of an ohm between them then it is probably not a good idea.

All the grounds will be commoned so it will be fine to put the positive feed to the bed on the other rail and ground it through the Melzi. That way it makes good use of the two rails.

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[www.hydraraptor.blogspot.com]