QSC K10.2, Руководство по обслуживанию

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39 TD-001517-01
K.2 Series Service Manual
8.2 Testing the AC mains fuse and line filter components
By following this tip, the EMI shield does not need to be removed in order to test the AC mains fuse or line filter compo-
nents. Because there are only resistive and inductive components between the input and filtered output of the line filter, a
DMM can be used to probe the AC wiring connections noted below to test the line filter components.
Performing this test will determine if:
• AC mains fuse F41 is open
• Inductor L41 or L42 has a broken lead (intermittent connections may not
be detected though)
• NTC inrush filter R41 is broken or open (Figure 8.2.1)
Procedure
1. Disconnect any AC power from the amplifier module.
2. Remove the AMP/PSU metal cover (which holds the fan) to gain access
to the AC wiring harness.
3. Disconnect the wiring harness from the AMP/PSU board and pull the
harness out of the heatsink for easy access.
4. Turn the power switch ON.
5. Using a DMM in
Ω
mode, make two separate measurements (Figure 8.2.2 shows the brown wires being probed):
• AC LINE
: One lead on the AC inlet terminal (brown wire), the other lead on the AC wiring harness pin (brown wire).
• Okay if short-circuit (less than 1
Ω
) is measured.
• If an open circuit is measured, the mains fuse F41 is probably open. Alternatively, inductor L41 or L42 could also
have broken leads.
• AC NEUTRAL
: One lead on the AC inlet terminal (blue wire), the other lead on the AC wiring harness pin (blue wire).
• Okay if 10
Ω
is measured.
• If an open-circuit is measured, NTC inrush resistor R41 is probably broken or open. Alternatively, inductor L41 or
L42 could also have broken leads.
Figure 8.2.1 - Broken R41 component
Figure 8.2.2 - Measurement locations for testing the AC line filter board components