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2-2 (E)
BKPF-L752
2-2. Preparation for Adjustment
1. Extend the DAC-38 board with a extension board.
2. Write down the customer settings of the switch (S3) on
the DAC-38 board in following table.
3. Set the switch S3 as follows:
Ref. No. (Address) Setting at adj. Customer setting
S3 (F-1) No. 1: OFF OFF
No. 2: OFF OFF
No. 3: OFF
No. 4: OFF
4. Install the main board (ADC-40 board) of the audio
A/D converter board (BKPF-L751’s audio input/
output gain in a factory default condition) to the
interface unit.
Factory default condition (RV405, 406, 407, 408/
ADC-40 board):
Each VR was completed the adjustment so as to
convert a +4.0 dBm to _20 dB FS.
5. Install the connector panel of the audio A/D converter
board (BKPF-L751) to the interface unit after setting
the LOOP/WORD switch to WORD CLK OUT (upper
position).
6. Turn on the power of equipment, and warm up them
for about ten minutes.
2-2. Preparation for Adjustment
2-3. Power Supply Voltage Adjustment
2-3. Power Supply Voltage Adjustment
Measuring equipment: Digital voltmeter
1. Set the digital voltmeter as follows:
Range: AUTO
Mode: DC V
++
++
+5 V adjustment for Analog line
2. Connect the probe of the digital voltmeter as follows:
+: TP1/DAC-38 (G-2)
_: E7/DAC-38 (C-2)
3. Adjust the voltage on the digital voltmeter.
Adjustment point: 1RV1/DAC-38 (G-2)
Specification: 4.75 ±0.05 V dc
++
++
+5 V adjustment for Digital line
4. Connect the probe of the digital voltmeter as follows:
+: TP2/DAC-38 (F-2)
_: E2/DAC-38 (F-2)
5. Adjust the voltage.
Adjustment point: 1RV2/DAC-38 (F-2)
Specification: 4.75 ±0.05 V dc
±12 V adjustment
6. Connect the probe of the digital voltmeter as follows:
+: TP3/DAC-38 (D-3)
_: TP4/DAC-38 (D-3)
7. Adjust the voltage.
Adjustment point: 1RV3/DAC-38 (E-2)
Specification: +25.10 ±0.05 V dc
8. Connect the probe of the digital voltmeter as follows:
+: TP3/DAC-38 (D-3)
_: E7/DAC-38 (C-2)
9. Check the voltage.
Specification: +12.55 ±0.15 V dc
10. Connect the probe of the digital voltmeter as follows:
+: E7/DAC-38 (C-2)
_: TP4/DAC-38 (D-3)
11. Check the voltage.
Specification: _12.55 ±0.15 V dc
n
After adjusting the power supply voltage, be sure to
perform “2-4. Input/Output Gain Adjustment”.
DAC-38 Board (Side A)
S3
ON
1234
E3
E6
E8
E1
E2
TP1TP2
RV1
1
RV2
1
RV3
1
D3
D814
D815
RV101
RV201
RV301
RV401
E4
E7
TP4
TP3