My Retevis RT97S repeater had been on-line continuously for just over 2 years serving my neighborhood when it failed. My inspection revealed that the voltage regulator chip on the PC board CD-900DYB was burned. I determined that the power supply was in good working order so I ordered and received a replacement PC board. I installed this new PC board and on power up, it to blew the voltage regulator chip in about 2 seconds. At this point I am looking for professional service on this unit that is just out of the warrantee period. So far in my search on the Internet, I am not finding any servicing provider. If I am unable to find service on this repeater, I will never purchase another Retevis repeater and this one will be sent to the scrap pile, reluctantly! Karl, in Warren, Michigan, USA