Mounting The Updated Amplifier Board To The Super Heat Sink; Figure 15-Mounting Assembled Pcb To Super Heat Sink - DYNACO STEREO 120 Updating Instructions

Mounting the Updated Amplifier Board to the Super Heat Sink

Figure 15-Mounting assembled PCB to super heat sink

1. In addition to the assembled circuit board with the mounting brackets in place,
have the following items ready:
a. The super heat sink plate
b. 4-40 screw (callout 4 in Figure 15).
c. Qty 2 of #6 fender washers, and Qty 2 of #6-32x1/2" pan-head screws
(callouts 6 and 7 in Figure 15). These screws were once used for the C7
right and left mounting brackets.
d. Thermal compound
2. Cut a corner of the 4-gram packet of thermal compound. If you use it
appropriately, that's enough to do everything you need. Place a line of thermal
compound onto the back of the LM3886. Use your finger to smear the line into a
thin film covering on the back of the LM3886. Save the rest of the thermal
compound for other steps in the assembly.
3. Assemble the LM3886 and circuit board to the heat-sink plate as shown in Figure
11, using the 4-40 screw into the tapped hole as shown, just finger-tight.
4. Square up the assembly of the circuit board to the heat sink, and use the #6 screws
and fender washers to fasten the brackets to the heat sink. The #6 screws and
fender washers leave enough wiggle room to make assembly fairly non-critical.
Just make everything finger tight at first to make sure it all looks even and fits
well without strain.
5. When everything looks good, progressively tighten all the hardware.
6. Tighten the #4 screw that holds the LM3886 to the heat sink. Both the tab and
heat sink are metal, so you can tighten it firmly.
7. Repeat the process to build the amplifier module for the second channel.
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