WhitakerAudio J C Whitaker 20 W Stereo Audio Amplifier, Manual

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57
20 W Stereo Audio Amplifier
– Install R6, R7 – 15 k
Ω
, 2 W, 1% . Solder in place, providing about 1/4-inch clearance
above the board.
– Install R8 – 3.9 k
Ω
, 2 W . Solder in place, providing about 1/4-inch clearance above the
board.
– Install R9, R10 – 100 k
Ω
, 0.5 W, 1% . Solder in place.
– Install R11, R12 – 1 k
Ω
, 0.5 W, 1% . Solder in place.
– Install R37, R51, R61 – 220 k
Ω
, 2 W . Solder in place, providing about 1/4-inch clearance
above the board. R61 is located on the rectifier PWB.
– Install R65 – 100 k
Ω
, 2 W . Solder in place, providing about 1/4-inch clearance above the
board. R65 is located on the rectifier PWB.
Clean the soldering iron tip before proceeding.
Note that D51 and other diodes are sensitive to static discharge. Take appropriate measures to
minimize the possibility of component damage due to static electricity. Note that the electrostatic
protection packaging may not be recyclable.
– Install D51 – rectifier, 2 A, 1 kV . This diode goes on the rectifier board. Solder in place,
providing about 1/4-inch clearance above the board. Be certain to observe proper polarity.
Note that the banded end of the diode connects to the square pad on the PWB. This same
convention is used for all other diodes.
– Install VR51 – power thermistor, 10 Ω cold . Solder in place, providing about 1/2-inch
clearance above the board.
Clean the soldering iron tip.
– Install C1 – 47 µF, 450 V electrolytic . Solder in place. Be certain to observe proper
polarity. The positive terminal of the device connects to the square pad on the PWB. This
same convention is used for all other electrolytic capacitors on the board.
– Install C2, C4, and C5 – 0.22 µF, 400 V, 5% . Solder in place.
– Find C3 – 3.3 pF, 1000 V, ceramic or mica . Set aside for now.
– Install C13 – 20 pF, 1000 V, ceramic . Solder in place.