Yamaha XS250 서비스 매뉴얼 - 페이지 13

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Yamaha XS250에 대해서도 마찬가지입니다: 소유자 매뉴얼 (15 페이지)

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INSPECTIONS

A STEREO and PARALLEL Operation

Before performing any following adjustments, set the unit as follows:

Set the ATTENUATIONS at the MAX.

Input terminal:

Cannon connector pin 2 is HOT, pins 1 and 3 GROUND.

MODE switch:

STEREO

Output terminal:

RL = 4 ohm/more than 500 W

Others:

Both Channel operation is required, if no particular indication. Moreover, turn off the filter switch,

if no particular indication.

Adjustment Specifications

1. Fan Test

When turning on the power switch, confirm that both fans of right and left sides regulate at low speed.

2. Muting Test

After applying power to the unit, the PROTECTION indicator should remain ON 2.5 +/-1 seconds to indicate that the protection circuitry

is operating and the indicator should go out. NO signal is output while this indicator lit.

3. Idle Current Test

Connect the input terminal to the GROUND and adjust the VR201 (A channel) and VR301 (B channel) that the DC voltage Vb between the

pin 1 and pin 2of the CN202 (A channel) and the CN302 (B channel) should be 1.0 +/-0.2 mV. And After finishing all tests, adjust the Vb

again to 1.0 +/-0.2 mV.

4. Input Terminal DC offset

Connect the input terminal to the GROUND and check that the DC voltage Vdc of the output terminal should be 0 +/-75 mV.

5. Gain Test

Check that the OUTPUT should be +22.1 +/-0.5 dBu, when a sine wave of 1 kHz at -10 dBu is applied to the INPUT. This test should be

performed on PARALLEL operation.

6. Frequency Response Test

Filter switch OFF:

When a sine wave of 20 Hz, 1 kHz or 20 kHz at -10 dBu is applied to the INPUT, check that the output is 0 +/-0.5 dB at 20 Hz and -0.5 +/-0.5

dB at 20 kHz taking the 1 kHz as a reference.

Filter switch SUB WOOFER:

<MIN>

When a sine wave of 25 Hz, -10 dBu is applied to the INPUT, check that the output is -3.5 +/-1.0 dB taking the 1 kHz as a reference at the

filter switch OFF.

<MAX>

When a sine wave of 150 Hz, -10 dBu is applied to the INPUT, check that the output is -3.5 +/-1.0 dB taking the 1 kHz as a reference at the

filter switch OFF.

Filter switch LOW CUT:

<MIN>

When a sine wave of 25 Hz, -10 dBu is applied to the INPUT, check that the output is -4.5 +/-1.0 dB taking the 1 kHz as a reference at the

filter switch OFF.

<MAX>

When a sine wave of 150 Hz, -10 dBu is applied to the INPUT, check that the output is -3.5 +/-1.0 dB taking the 1 kHz as a reference at the

filter switch OFF.

XS250/350