This is the best place to ask detailed questions about the P4455 or Argus 2 camera and accessories from EEV.
Several of the members have these cameras and can advise regarding repairs and offer or exchange spare parts.
The cameras are export controlled (US EAR) so discussion should not disclose details regarding the Raytheon sensor itself and the immediate electronics as this board is visible worldwide.
Any exchange of parts between members is their own responsibility and should be carefully considered to avoid any issues with export control. If in doubt consult national authorities.