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8.3 Bypassing the AC line filter
If you would like to power up the amplifier module without the AC line filter, build a custom wiring harness like pictured in 
Figure 8.3.2. By injecting AC into the AMP/PSU board directly, the AC line filter is bypassed. This tip is especially useful if 
you want to power-up the amplifier module and check basic functions, but can’t because the AC mains fuse is open. 
 Warning: Risk of electrical shock! Proceed with extreme caution when using this method.
Perform safe testing practices
•  Always have an external fuse (5A or less) or resettable current trip device connected in line with the AC wires.
•  Use a rated power switch to apply AC power to the board. Hot-plugging is not recommended. 
•  Be very careful of any exposed conductors on the custom wire harness. AC is present on these exposed conductors!
•  Do not run full-power tests when the AC line filter is bypassed.
Testing notes
•  An example connection using a custom wiring harness is seen in Figure 8.3.1.
•  This tip should only by performed to check basic amplifier functions and to determine if the AC line filter board is bad. 
•  Do not perform final amplifier bench tests with the AC line filter bypassed. The amplifier will not pass all tests due to the 
unfiltered AC input.
 
Figure 8.3.1 - Bypassing the AC line filter using a 
custom AC wiring harness
Figure 8.3.2 - Custom AC wiring harness for K.2. Add a resettable 
3A circuit breaker in series for added protecetion (not pictured).