TB8100 Service Manual Safety and Servicing Information 23© Tait Electronics Limited September 20061.6 Identifying Screw Types1.6.1 Torx Recess Head ScrewsTorx recess head screws are the standard type of screw used in all TB8100equipment, although Pozidriv and Allen recess head screws are also used ina few special applications.Figure 1.2 below shows a typical Torx recess head screw (actual hardwaremay differ slightly from this illustration due to variations in manufacturingtechniques).1.6.2 Allen Recess Head UNC ScrewsAllen recess head 4-40 UNC thread screws are used to secure the RF powertransistors in the TB8100 power amplifier and cannot be interchanged withM3 screws (refer to Figure 11.1 on page 197).1.6.3 Pozidriv Recess Head ScrewsPozidriv recess head screws are used in TB8100 equipment in a few specialapplications. It is important that you use the correct type and sizescrewdriver to avoid damaging the screw head.It is particularly important that you do not use Phillips screwdrivers onPozidriv screw heads as the tapered driving flutes of the Phillips screwdriverdo not engage correctly with the parallel-sided slots in the Pozidriv screwhead. This can result in considerable damage to the screw head if thescrewdriver tip turns inside the recess.Figure 1.2 Identifying Torx screws“star” shaped recess withsix internal notches
