WhitakerAudio J C Whitaker 20 W Stereo Audio Amplifier, Manual

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WhitakerAudio
5.3 Assembly of the Preamplifier Power Supply Module
Check the shipping box for the major component groups. Find the preamplifier power supply box.
Set the other boxes aside for now. Organize the components in a logical manner, grouping
resistors together, capacitors together, and so on. Note that a schematic diagram of the
preamplifier power supply is provided, along with a copy of the PWB component layout. The
component layout sheet is a useful reference as many of the part numbers are obscured when the
components are installed. The estimated time required to complete assembly of the preamplifier
power supply PWB is one hour.
After reviewing the Construction Techniques section of this manual, begin populating the
board. As the packing envelopes are used, set them aside for recycling. Before beginning, clean
the soldering iron tip.
– Install the “quick disconnect” male tabs using the pads provided on the board. There are 5
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 so as to face the same
direction for all posts.
The proper procedure is illustrated in Figure 5.1.
Clean the soldering iron tip before moving on to the following steps.
– Install R301 – 5 k
Ω
, 10 W . Solder in place, leaving about 1/2-inch clearance above the
board.
Caution: leads may tend to fly toward the face when they are cut. Wear protective glasses. For
all steps that follow, excess lead length should be trimmed after the component is soldered in
place.
– Install R302, R305 – 220 k
Ω
, 2 W . Solder in place, leaving about 1/2-inch clearance
above the board.