CPC T-REX power supply

[Nemesed17]

I was lucky enough to find a Terasic C1 development kit in good condition, and my goal is to get out of this a fully operational CPC T-Trex. However, the PSU is missing in the box. I need a 9V DC  power adapter, but i don't know about the pin polarity and I don't want to fry the FPGA board. I assume the + is at the center and the - around like it is more often the case (I know only the Sega Megadrive not following this configuration). Could somebody help me to solve this little enigma? Thanks in advance!

[pelrun]

Power it via USB as per the manual?

[Bryce]

The pin on the side of the socket is the outer contact. Check whether this goes to the positive or negative of the first electrolytic capacitor in the regulator circuit.

Bryce.

[Nemesed17]

To Pelrun: yes it could be a solution but I prefer to keep that for the data transfer from the PC (from the Quartus II software, USB blaster function, I could use the RS232 port for that, but it is less handy). Plus, if I use the USB, shoud I use a  9v USB PSU (excuse me but I am a total ignorant when it comes to electricity, above ll in electronics). Thanks for the solution.
To Bryce: it is difficult for me to read a circuit board, I can't determine exactly what i have to see. Thanks  for the reply.

[Bryce]

USB is 5V (even though fast chargers have broken the rules and made devices that go up 12V).

Take a clear photo of the top and bottom of the PCB and I will show you how you work out the polarity.

Bryce.

[Nemesed17]

Thank you very much Bryce for your help, in the meantime I contacted Terasic in Taiwan, they sent me the  specs (with schmatic) of the PSU: 7,5V-800 mA, "+" at the center.
Thanks again for the dedication.