Identifying positive/negative wires?

I'm about ready to plug in my Prusa, but I'm uncertain about the positive/negative connections to the Gen6 board. Cutting and stripping the cable from my HQ power supply (from Mendel-Parts) has revealed two wires. The inner wire is coloured pure white. The outer wire is exposed and seems to be twisted around the white wire, but it lacks any coating beyond the black protective layer that conceals both wires. I've tried searching the internet, but haven't found any universal method of identifying positive/negative wires, and I'm only prepared to make a decision if I'm completely sure it's the right one. If anybody can confidently say which wires are positive/negative in a HQ adapter then I would very much appreciate their input! I don't have a multimeter btw.

Thanks!

You need to get a meter and measure it. These are less than £5.00 so there is no excuse for not having one.

Unfortunately, the only meters I can find for £5 or less are sold online, and could potentially take a week to arrive. Pretty annoying considering it is probably the only item I need to get up and running! I can get a multimeter locally for about £10, and that is probably what I will need to do if Mendel-Parts don't get back to me with some definite answers about their HQ power supply wires soon. I just don't like spending £10 on a £4 multimeter, and I don't like waiting too.

I just raised the question here in case there were plenty of people using the HQ power adapters that Mendel-Parts sell.

... use a LED with a resistor of some kOhm in series - it lights only if the positive potential is connected to the long pin and the negative (e.g. over the resistor) to the short pin, marked by a flat on the diode-housing ...

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Viktor
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Dip the wires in a solution of copper sulphate, the one that gets coated in a copper film is the negative.

Thanks for the tips, but the problem is solved now!

Mendel-Parts got back to me and said that the outer wire is negative and the core (white wire) is positive. I've compiled Repsnapper for Linux and had a chance to send a few GCodes to test the various axis. Very early days, but so far so good.

I'll probably order a cheap multimeter anyway, I want to be better prepared in future!

My advice would be to get a multimeter with a thermocouple probe. That and a digital calliper are indispensable for setting up these machines.

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[www.hydraraptor.blogspot.com]