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1-28. Prepare a 5.5" length of BLACK wire and solder one
end to the (-) side of "Vcc EXT".
1-29. Prepare a 4.0" length of RED wire and solder one end
to the pad in the "Power Switch" nearest the position for R15.
1-30. Prepare a 5.5" length of WHITE wire and solder one
end to the (+) pad on the "AUDIO OUT" box outlined on the
board.
1-31. Prepare a 5.5" length of BLACK wire and solder one
end to the other (ground) pad in the "AUDIO OUT" box.
1-32. Lightly solder the white (+) and black (-) wires from
"AUDIO OUT" to the(+) and(-) lugs of the 3'' speaker in your
kit. Because this is a temporary connection, you also may use
alligator clip jumper wires. These two wires will be soldered
permanently to the phone jack later.
Phase 1 Optional Progress Test
The purpose of this test is to make sure that the amplifier section
is working property. If it does not, installing more parts will not
fix it!
1-33. DOUBLE-CHECK all preceding assembly steps.
1-34. Connect any 11-14 volt DC voltage source to the red
(+ ) and black (-) wires.
1-35. Turn the volume control all the way up.
At this point you should be hearing a gentle background hiss and
perhaps a soft AC hum. Now, touch one end of R10 with your
finger or a voltmeter test lead: you should hear a strong AC hum.
Rotating the volume control will have the same effect as any
volume control. These are the ONLY sounds you should hear.
There must NOT be any popping, putt-putting or squealing. If
there are ANY such sounds, it means that the amplifier is
oscillating, caused by some error in preceding steps. Make sure
you have the amplifier working properly before proceeding.
1-36. Disconnect the battery or power supply.
1-37. Disconnect the speaker.
1253 - 21
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