Works!
At least with my display it is possible to power it by usb just with 2 wires without the need to modify anything else.

Great.

If I need to, I can still use 12 V with the other connection.

Thanks all!

Thanks for your answers, I will look up that later. I did it similar without removing anything: http://s1.directupload.net/images/130224/lj8v6w9f.jpg The big advantage is, that you can do this without any advanced soldering skills. :) ... One thing wonders me... What do you think, what if I give usb...

My power source delivers 14.2 V

Taking the dot as base, I have the following measurements:

...to the cable connector
^
I
-12,21 | -12,21 | -12,21 | -12,21
PIN1 | -6.71 | -7.17 | -12.21
I
`´
to the capacitors

If I get minus measurements, I think PIN1 is not PIN1, what do you think?

In between I have bought a 12 V 1 Ampere switched power source and the display runs fine with the raspberry pi. I took pictures of the voltage control chip: http://s7.directupload.net/images/130731/temp/wkkf7379.jpg http://s14.directupload.net/images/130731/temp/xujgx4bs.jpg It reads XD1509 -5.0E1 3...

Refering to postings at page 4 I have the same board Kronalias has posted a youtube video about Fri Feb 22, 2013 4:12 pm and dasimpson assumes Fri Feb 22, 2013 4:45 pm that it is sufficient to shorten 12 and 5 Volt pins of the voltage control chip (is this correct?). I'd like to do that because it i...