Today circling my head, I saw through a resistance of 10 k, fed to 12 volts in the circuit psudo 5.6 V supply. I had changed the 5v regulator, but this did not, thought the regulator 12 v I have not changed may be in poor condition and not supplying the current. 

I have a power supply source some laboratory 

I thought I provided the voltage and got up residence on one side and the diode cathode part, on the other hand, my surprise is that at 12 I still have tp voltage. You know where you can come that voltage. 

Thank you. 

Victor.