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ADJUSTMENTS
The adjustment procedures for this IC using an oscilloscope are described below.
TD6704P (ANALOG/DIGITAL) ADJUSTMENT
1. Make the input signal of the left and right channels 0 volt (in source pause or input open status), and rotate the semi-fixed
potentiometers R623 (5k ohms) and R624 (5k ohms) to adjust the output voltage at the test points TP4 (Q606 Pin (7)) and TP3
(Q607 Pin (27)) for 4.0 volts.
Refer to Figure A.
2. Apply trigger to the test point TP2 (Q607 Pin (7)) and observe the TP1 (Q607 Pin (10). The oscillator indicates as shown on the
(a) and (b) of Figure B, rotate R625 so that the "H" levels become as small as possible (Figure B, (c)). If there is unbalance in
the level between the right channel and left channel as shown figure B (d), slightly rotate R623 and R624 to balance the level
between 2 channels and then repeat the above procedures.
XB-1000
Oscilloscope
TPI~TP4
4
J
GND
LIGHT UP SENSITIVITY ADJUSTMENT
At the factory, the sensitivity of detector circuit is adjusted so that the LED starts to illuminate when the voltage becomes 500mV
at the Dolby test point. The adjustment procedures used in the factory are as follows:
(1) Take out the DSP unit from the case. Pull out the plastic rivet holing the PC board and unfold the double-folded PC board.
(2) Feed sine wave of 1kHz 350mV from a signal generator to the CD analog input terminal (left or right only).
(3) Apply the power to XB-1000 and set to the CD analog input, Dolby surround DSP mode.
(4) Rotate the INPUT LEVEL potentiometer so that the signal level becomes 500mV rms at Dolby test point (Q604 Pin (2)).
(5) Rotate R765 (located beside the microprocessor) on the PC board so that the "OVER" LED just comes on.
Oscillator
XB- 1000
Oscilloscope
KHz
350mVrms
PCM56P (DIGITAL/ANALOG) ADJUSTMENT
The followings explain the adjustment procedures of D/A converter.
(1) Remove the DSP unit from the main unit's chassis. Pull out the plastic rivet holding the PC board and unfold thePC board. In
this process, keep all the connection cables for input and output connected.
(2) Place the unit to the Digital In mode.
(3) Reproduce the test signal of OdB (against full-scale), for example 1th track of YEDS7, by a CD player having the digital out fea-
ture and feed it-to the this unit in digital signal.
(4) Adjust R643 and R644 so that the signal distortion rate for the left and right channels at the output terminal J7(1 of the DSP
unit becomes minimum.
XB- 1000
CD Player
Distortion Meter
DIGITAL
OUT
YEDS?
PLAYBACK
Ses fe
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