WhitakerAudio AM/FM Stereo Tuner 2012, Сборка и руководство пользователя

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• Use only the amount of heat and solder necessary to do the job. Once a PWB is damaged
by excessive heat it is very difficult to repair. Excessive solder flux on the board will tend
to attract dust, which—at high voltages—can lead to arc-over problems.
• Inspect each solder connection to be certain that the mounting pad or via has been filled.
• Mount large components last. These typically include barrier strips and high-voltage
electrolytic capacitors.
All audio cables of length greater than about 6 inches should use shielded cable. Generally
speaking, the shield should be connected to ground at the load end. Grounding both ends of a
shielded cable to the same ground plane is not recommended as it may lead to circulating currents
that will adversely impact the noise floor.
Efficiently making the socket connections to the PWB requires a bit of practice. The
recommended procedure is detailed in Section 5. Be certain to wear protective eye glasses during
this process, and at other steps in PWB assembly.
The chassis is painted and the power transformer and choke are shipped painted. To ensure
that the cases are grounded, a ground lug is attached to each device. This is important for safety
reasons. While quite rare, transformer failures can occur. One failure mode can be a shorting of
one of the windings to the transformer case. By grounding the case, such a failure would open the
circuit breaker and prevent dangerous voltages above the chassis in a fault mode.
Because nearly all of the components are mounted on the PWBs, construction of the tuner is
relatively straightforward. A decorative Plexiglas shield is supplied and can be used over the
tubes and transformers if desired.