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15
The amplifier PCB is placed in the center on the heatsink, 1 mm from
the edge where C1 is located, and fixed temporarily with sellotape so
the six positions for the metal standoffs can be marked out (scored).
Use a 3.5-mm drill bit and with some pressure turn it counterclockwise
in the six holes located at the short sides of the PCB, taking great care
to avoid damage to the PCB. Do not score the positions K3 and
K4. Being the outputs of the amplifier, they must never be in electrical
contact with the heatsink! All six holes are located at ample distances
from the heatsink fins to allow room for the screw heads including a
small error margin.
Figure 12. Standoffs secured in place for the PCB to be mounted.
After the six 3-mm holes are drilled, the six 10-mm standoffs are
mounted on the heatsink and fastened with the black 12-mm M3
screws. Next, check if the PCB fits accurately on the six standoffs. If
not, consider filing out one or more holes to slightly correct the position
of the standoff(s).
4 – Locating and Drilling Holes in the Heatsink, for the PCB Standoffs
