7.2 Preliminary Adjustments
These adjustments are performed when first receiving the machine, and then again only
when an audio component, such as the Heads, is replaced.
7.2.1 Peak Indicator Level Adjustment
NOTE: The PEAK indicator is factory preset to illuminate at a level equivalent to 1040 nWb/
m, which corresponds to approximately 3% THD.
1. Check the trigger level corresponding to the set Magnetic Reference Flux
Level.
Magnetic Ref. Flux Level Trigger Level
185 nWb/m Standard Level + 15.0 dB
250 nWb/m Standard Level + 12.4 dB
320 nWb/m Standard Level + 11.2 dB
2. Connect an oscillator to the CH1 INPUT connector, adjust the oscillator so
that it generates a sine wave (1 kHz) at the trigger level. Confirm that neither
of the internal Test Oscillator buttons are pressed.
EXAMPLE: Set the oscillator to +16.4 dBu when the Magnetic Reference Level is
250 nWb/m and the Reference Level is +4-dBu.
3. Set the Monitor button to SOURCE position (not depressed).
4. Adjust VR701 for CH1 and VR801 for CH2 on the VU Meter Amp PCB which
is located behind the VU meter so that the peak indicator illuminates at the
trigger level.
7.2.2 Test Oscillator Waveform and Level Adjustment
Perform this adjustment after the Level Matching Adjustment (§7.2.1) has been completed.
1. Set the Monitor button of CH1 to SOURCE position.
2. Press the 1 kHz TEST OSC button on the Amplifier Panel.
3. Adjust VR502 on the REC/REP AMP PCB Assembly (see Figure 7-1) so that
the VU meter indicates 0 VU. Perform the same adjustment to the channel 2.
4. Press the 10kHz OSC FREQ button.
5. Adjust VR501 so that the VU meter indicates 0VU.
MX-5050mkIV-2/BIII-2 Operation and Maintenance Manual
1999-02 45
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