Was the C5 only on the S9 or was it in the S9i – 14 TH ?
C5 control board works on both s9 and s9i and c5 cotrol board is mostly used old firmware and you will never upgrade it to latest firmware.
So I suggest you better to use any Xilinx control board as suggested above. It's compatible with any s9 series hashboard.
They have also supported the latest s9 firmware available from bitmain download page and supported SD card flashing compared to the c5 control board.