MK179 Proximity reader

Hi,
I buillt this card reader quite a long time ago but never used it. I’m pretty sure it was functioning correctly then. I now find that when powered the led illuminates and the relay clicks immediately and they stay that way. The PIC seems warm and it is likely something I have done…

Is the PIC available separately? Or the firmware? I can program one if it’s available.

Any help gratefully received.Thanks.