MK179 doesn't work

Kits Mini Kits Range
1

I bought the MK179 rfid reader and assembled it. Before soldering I checked all resistors with my multimeter. They were all ok, including R9 and R10. When I connected power to the kit it did nothing, just a really weak led blink every half second. What could be the problem?

The first adapter I connected said 12VDC on the cover. When I measured it, it turned out to be 18 Volts. Later I connected a balanced 12VDC power supply. Did I screw up by overpowering it?

I use a short wire for the antenna.

Please help!!

2

Edit:

I checked the power supply connection point of the PIC 12F629. They gave a perfect 5Volts. So the voltage regulator seems to work just fine.

3

You use a short wire as antenna ???
Please explain.

4

I connected the antenna with a wire that isn’t too long. Even though the manual says its possible too use a wire with a lenght up to 5 meters. I thought it might be worth mentioning,