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c.
Connect the Brown wire from the C7RNEG eyelet on the board to the
negative terminal of C7R. C7R is near the front panel.
d.
Connect the White wire from the C7RPOS eyelet on the board to the
positive terminal of C7R. C7R is near the front panel.
6.
Do a trial fitting into the chassis without the screws. Take this time to push
various wires out of the way to clear the way for the amplifier module. Once you
see that there’s a clear path to installing the amplifier module, proceed to the next
step.
7.
Use the spare thermal compound reserved previously to “butter” the bottom edge
of the heatsink with a thin film of thermal compound. This will help transfer heat
to the chassis, and lets the amplifier idle about 2 degrees C cooler.
8.
Insert the 6-32x3/8” sems screws (have built-in lockwashers) thru the bottom of
the chassis and tighten them up to hold the heatsink in place.
9.
Connect the RED/BLACK power wires from the amp PCB to C9:
a.
RED wire from VCC to the positive terminal of C9.
b.
BLACK wire from PGND to the negative terminal of C9.
10.
Inspect your work:
a.
Make sure there are no pinched wires.
b.
Form the wires to satisfy your sense of neatness.
c.
All of the label eyelets around the border of the PCB should have a wire
installed.
Test your work
Caution: Potentially fatal voltages will be present. This is not the time to get sloppy!
Bare amplifier tests
1.
Turn the power switch off.
2.
Plug the amp in to the AC mains.
3.
Working at arms length from the amplifier,
turn the amp on and watch for
smoke. If no smoke, then continue. (Of course, if smoke, then pull the plug and
take a break).
4.
5 to 10 seconds after turn-on, the LED on the amplifier board should illuminate,
and you’ll hear the relays click if the room is quiet.
5.
Check the voltage on C9. It should be about 72 volts DC. It isn’t a regulated
voltage, so it may range from 66 to 78 volts.
6.
Turn off the power switch. The LED turns off almost immediately when the
power switch turns off.
Amplifier plus speaker tests
1.
Hook a pair of speakers to the FRONT speaker outputs.
2.
Turn the volume down and set the selector switch to TUNER. Set the speaker
switch to FRONT.
3.
Turn the amplifier on. There may be a “tick” sound when the relays close, but it
should be quite soft. The amplifier should otherwise be quiet.
4.
Temporarily set the top cover back in place. Note that on the SCA80(Q), having
the top cover in place greatly diminishes hum.
