Making The Speaker Binding Posts User Friendly; Section 7: Testing The Completed Amplifier; Test #1 - DYNACO STEREO 120 Updating Instructions

7. Check your work. One OGND terminal will not have a wire, and the following
eyelets on the PCB should each have a wire:
e. VCC
f. PGND
g. IGND
h. IGND
i. INPUT
j. OGND
k. OUTPUT
8. Make sure that the bottom lip of the heat sink is clean, and also the place where it
mounts to the chassis. Place a line of thermal compound along the bottom of the
short part of the heat sink. Smear it into a thin film using a finger.
9. Mount the heat sink to the chassis using salvaged 6-32x1/2" hardware. Remember
that the outside mounting screw also carries a mounting foot.

Making the Speaker Binding Posts User Friendly

The speaker binding posts have holes for the speaker wire. These holes should be
oriented from side to side, not up and down, to allow easy connection of the speaker
wires. If your binding posts are already correctly oriented, skip this step. If not, use this
procedure to whichever of the 4 binding posts don't have the correct orientation:
1. Loosen the binding post (red or black plastic part) until you can see the hole in the
mounting stud.
2. Loosen and remove the nut that holds the speaker connection wires. Remove the
speaker wire lugs, noting their locations so that they may be correctly returned.
3. Loosen the remaining nut just enough to be able to spin the binding post to the
correct orientation. Hold the binding post in place by passing a nail through the
hole, and tighten the mounting nut.
4. Replace the solder lugs with the speaker connection wires.
5. Replace and tighten the nuts that hold those lugs in place.

Section 7: Testing the Completed Amplifier

It's best to test the completed amplifier one step at a time. In that manner, if you have
something wrong, you may damage the amplifier module, but you won't damage your
speakers.

Test #1

1. Disconnect signal inputs and speakers from the amplifier.
2. Turn the power switch off.
3. Plug in the amplifier.
4. Turn the power switch on.
5. Observe the amplifier for a minute.
a. It will make a "bong" sound when you turn on the power, but after that
you should hear only a soft humming sound from the power transformer.
b. Watch for smoke. There should be no smoke. If you see smoke, turn off
the amplifier immediately, take a few deep breaths, and refer to the
troubleshooting section.
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