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Final Inspection of the Circuit Board
After you’ve taken a break, look over your completed circuit board(s) one more time.
Looking on the component side, double check:
1.
polarity of diodes matching the banded end on the silk screen.
2.
polarity (flat side of LEDs).
3.
Polarity of the electrolytic capacitors.
If you get one of these polarities wrong, there is a good chance that the amplifier won’t
work, or there will be damage when you power it up.
Look at the solder side of the board. Make sure that:
1.
All component leads are soldered (it’s easy to forget one or two, and that will
cause either unreliable operation, or no operation at all!)
2.
There are no solder bridges between pads which should be isolated. Solder
bridges may stop the amplifier from working correctly.
Install the Power MOSFETS and Mount the Amplifier Board to
the Heatsink
You’ll repeat the process described in this section two times, once for each amplifier
module. We’ll show the details for the amplifier that mounts to the right-hand side of the
heat sink
6
.
Figure 21-Mounting assembled PCB to heat sink
1.
Use two 6-32x3/8” screws to fasten a pair of mounting brackets to the heat sink,
placing the screw through the non-threaded hole in the bracket. Don’t tighten the
screws yet.
2.
Use two 6-32x1/4” screws to fasten the PCB to the mounting brackets and heat
sink. Don’t tighten the screws yet.
6
Paradoxically enough, this is connected to the LEFT channel ins and outs.
