JBL EON15 Introduction And General Information page 38

3) Low Mid Frequency Band: Using the Mic input at mic level (i.e. Switch SW1 in), set
the input signal to –60dBu at 400Hz. Verify that the output at pin 1 of J1 is approximately
9.3 dBu.Turn Low Mid Frequency EQ control fully clockwise and verify that pin 1 of J1 is
now approximately 21.6 dBu. Turn same knob fully counter clockwise and verify that pin 1
of J1 has now decreased to –3 dBu. If none of the above is true, check U8A, C46, C47,
R60, R65, R64, and all traces/solder around them. If all the above is true, set knob back to
center detented point and go to the next frequency band.
4) High Mid Frequency Band: Using the Mic input at mic level (i.e. Switch SW1 in), set
the input signal to –60 dBu at 2.5kHz. Verify that the output at pin 1 of J1 is approximately
9.3 dBu. Turn High Mid Frequency EQ control fully clockwise and verify that pin 1 of J1 is
now approximately 21.2 dBu. Turn same knob fully counter clockwise and verify that pin 1
of J1 has now decreased to –2.8 dBu. If none of the above is true, check U8B, C45, C56,
R74, R63, R59, and all traces/solder around them. If all the above is true, set knob back to
center detented point and go to the next frequency band.
5) High Frequency Band: Using the Mic input at mic level (i.e. Switch SW1 in), set the
input signal to –60 dBu at 12kHz. Verify that the output at pin 1 of J1 is approximately
9.0 dBu. Turn High Frequency EQ control fully clockwise and verify that pin 1 of J1 is now
approximately 21.2 dBu. Turn same knob fully counter clockwise and verify that pin 1 of J1
has now decreased to –3 dBu. If none of the above is true, check U7A, C43, R69, R58,
and all traces/solder around them.
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