are respectively provided in the nest and its cutout to vent the nitrogen gas provided by manifold 88 to the surface of the pcb the card carrier tray 50 also features side rails 162 fig9 which are situated to engage pneumatically actuated lifters 164 fig4 located at opposite ends of the conveyor 44 when the pallet 46 is in an initial position the lifters 164 are in an extended state for placement of the tray 50 thereon by the operator the operator then actuates a u201c start cycle u201d push button on the plc 52 and it actuates the lifters to lower the tray 50 onto the heating blocks 140 of undercarriage 130 key holes 166 fig9 are provided for this purpose upon completion of a pcb header assembly cycle the conveyor moves the pallet 46 to a track terminating position whereupon the plc 52 automatically actuates the lifters 164 to raise the hot tray 50 off of the heating blocks 140 and engage cooling fans 141 fig6 in order to enable the tray to cool somewhat before being removed by the operator fig1 is a functional block diagram of a control subsystem for station 40 as shown the plc 52 controls thermal loops 170 and 172 for the heating of the top and bottom heaters respectively of each cell 58 the plc 52 also controls the pneumatics of the conveyor 44 as described above to move the pallet 46 from the initial working to terminating positions and back if desired a position feedback means.