Board-PC cable

So, I'm currently setting up my 3d printer (Prusa-i3) so that it can work. This is my second attempt. First one ended with fried Melzi 2.0 and USB cable that connects board with PC (printer worked for some time although I couldn't calibrate it correctly). I've already replaced the old board, hooked it and gave it a run - for some unknown to me reason Z Axis is inverted, which forces me to access firmware. Now here's where trouble comes in - when I connect Melzi with PC, printer power goes down and monitor picture becomes distorted. I figured out that it has to do with my new cable.
Here's the pic:


The difference between my old and this cable is that the previous one had a cylinder in a place marked with red. So, should I get a new cable with a cylinder or is the problem lies somewhere else? Oh and what's the correct name for such cable? Thanks

Edited 3 time(s). Last edit at 06/09/2016 11:07AM by Gyoko.

I figured that the cable I had was USB Mini-b cable with ferrite core. So I guess I'll go buy that one, and notify you on my results

The ferrite core is just there to reduce interference. Your problem sounds like a ground loop and changing the cable isn't going to help. The most likely cause is a power supply problem.

I thought that it was a problem of power supply at first too - I used the cable twice for a short period of time and there were no problems, so I re-wired power supply just in case I have disrupted a contact somewhere accidentally, but the issue was still there... Which lead me to conclusion that it is a cable issue, but you're saying replacing cable won't change anything. So what do you suggest to do? Should I try re-wiring again or is there something specific that can cause the issue?

Quote
Gyoko
I thought that it was a problem of power supply at first too - I used the cable twice for a short period of time and there were no problems, so I re-wired power supply just in case I have disrupted a contact somewhere accidentally, but the issue was still there... Which lead me to conclusion that it is a cable issue, but you're saying replacing cable won't change anything. So what do you suggest to do? Should I try re-wiring again or is there something specific that can cause the issue?

1. Check very carefully that the cable(s) and connections between the negative output terminal of your PSU and the ground side of the electronics power input terminal(s) are sound.

2. Run the 3D printer and the PC and nothing else from the same mains power distribution block.

As well as reducing interference, the ferrite core on the USB cable reduces the chance of a mains-borne ground transient crashing the printer electronics/firmware.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].