WhitakerAudio J C Whitaker 20 W Stereo Audio Amplifier, Manual

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83
20 W Stereo Audio Amplifier
5.5 Assembly of the Power Management Expansion Board
Find the power management expansion board box. Set the other boxes aside for now.
– Install the “quick disconnect” male tabs using the pads provided on the board. There are 9
positions in all. Solder in place.
Note that the mounting pins fit tight into the board. This is normal. Use a pair of pliers to hold
the tab while inserting the pins into the PWB. Make sure the PWB is resting on a soft flat surface
while the tabs are installed. It is most efficient to install all of the tabs and then turn the board over
and solder in place. Be careful to not damage the board while installing the tabs. While not strictly
necessary, it is recommended that the flat side of the tab be oriented in the same direction for all
posts.
Clean the soldering iron tip before moving on to the following steps.
– Install R401, R407 – 4.7 k
Ω
, 0.5 W . Solder in place.
– Install R402, R408 — 5 k
Ω
, potentiometer, trimmer . Solder in place. Set for mid point.
– Install R403, R409 – 1 k
Ω
, 0.5 W . Solder in place.
– Install R404, R410, R413, R414, R419, R420, R423, R425 – 100 k
Ω
, 0.5 W . Solder in
place.
– Install R405, R411 – 820 k
Ω
, 0.5 W . Solder in place.
– Install R406, R412, R424, R426 – 22 k
Ω
, 0.5 W . Solder in place.
– Install R415, R416 – 1 k
Ω
, 2 W . Solder in place, leaving about 1/4-inch spacing above the
board.
– R417 – 10 k
Ω
, 0.5 W . Solder in place.
– Install R418 — 1 M
Ω
, potentiometer, trimmer . Solder in place. Set for fully clockwise.
– Install R421, R422 – 100 k
Ω
, 2 W . Solder in place, leaving about 1/4-inch spacing above
the board.
Clean the soldering iron tip.