An apparatus for holding a printed circuit board when mounting components thereon, said apparatus comprising a base plate, a mounting device for mounting a printed circuit board spaced from and substantially parallel to the base plate, a plurality of elongate support pins extending through respective holes within the base plate to extend transversely from the base plate, the support pins being independently positionable in height with respect to the base plate to define a configurable support surface for supporting components mounted on the printed circuit board during soldering, wherein the height that each pin extends from the base plate can be adjusted such that the support surface defined by the support pins can correspond to the topography of the circuit board and the components mounted thereon, a locking mechanism being provided for selectively locking the position of each support pin with respect to the base plate, wherein said locking mechanism comprises at least one elongate flexible member arranged to extend around a plurality of said support pins in convolute manner, tensioning device being associated with said at least one flexible member, whereby said tensioning device is adapted to selectively apply tension to said at least one flexible member to grip the pins around which said flexible member extends to lock the position of said pins with respect to the base plate.