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2.7.2. Ground lifting
Hum noise may be generated by a ground loop accidentally created through the PA link’s audio input.
In this case, the ground loop can be cut by setting the ground lift, which can be performed on the pc board of
PA link/BGM input board.
Step 1. Remove the top panel. (See Step 1 on
.)
Step 2. Take out the PA link/BGM input board to be set for ground lift.
Remove 2 screws at the corresponding channel’s board on the amplifier’s rear while holding the internal
PC board as show below.
The figure below shows an example of removing channel 1’s board.
PA link/BGM input board
PA link/BGM input board
Step 3. Cut the jumper J2 on the pc board.
Step 4. Replace the PA link/BGM input board and the top panel in the reverse procedures of removal.
Amplifier’s rear
BGM input
PA link/BGM input board
J2 (Ground lifting)
Cut to make ground lifting.
Viewed from the parts mounting side
