dbx 3BX III, Руководство по обслуживанию

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Model 3BX III Service Manual
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7.2 Expansion Magnitude and Timing
7.2.1 Set the unit as follows:
Expansion Maximum
Impact Restoration
Minimum
Transition Level Middle
Pre/Post Pre
Source/Tape Source
Bypass
Out (i.e., not set)
7.2.2 Connect the oscillator and tone-burst generator as in 7.1.2
and 7.1.3 above.
7.2.3 Low-Band Test
7.2.3.1 Set the sine-wave oscillator and the tone-burst
generator as in 7.1.4.1. (In this test, the 20 dB attenuation
figure is critical to achieving results consistent with the
pictures presented here.) Set the scope for 1 V/div and
50 ms/div.
7.2.3.2 Observe the output on the scope. Verify that the
shape is substantially as shown in Fig. 10a; confirm for the
other channel.
Figure 10a
7.2.3.3 Observe that the Low-Band display lights at least to
the 4
th
red LED during the burst and returns to the 2
nd
yellow
LED between bursts.
7.2.4 Mid-Band Test
7.2.4.1 Set the sine-wave oscillator and the tone-burst
generator as in 7.1.5.1 except for 32 cycles on instead of 8.
As before, the 20 dB figure is critical to achieving results
consistent with the pictures presented here. Set the scope to
1 V/div and 10 ms/div.
7.2.4.2 Observe the output on the scope. Verify that the wave
shape is substantially as shown in Fig. 10b, next page, and
then verify for the other channel.