RF Linear Amplifier PCB Assembly Manual
SkyWave DX600 Revision-B
Last Revised - 2/5/2021 9:10 AM
Page 44 of 57
Step #19 - Heat Sink Marking, Drilling, and Tapping
Place the PCB on the heat sink. Use masking tape or equivalent to hold the PCB still during the
marking process. Using a transfer punch
**
, carefully mark the center of the four PCB mounting
holes that contain the spacers, the RF transistor mounting holes, and the three device mounting
tab holes at the edge of the PCB.
Remove the tape and PCB from the heat sink. Use a center punch to enhance the marked centers
prior to drilling. Use a #42
(0.0935”)
drill bit to drill all marked centers.
Use a #4-40 tap to thread all nine drilled holes.
Figure 47
** A transfer punch is a punch of a specific outer diameter that is non-tapered and extends the entire length of the punch (except for the tip). It is used to
tightly fit the tolerances of an existing hole and, when struck, precisely transfer the center of that hole to another surface.