Sony CFD-G70 Service Manual page 15

CD SECTION
Perform all CD section check and all adjustments in the test mode.
How to put the set into CD test mode
1. Press the POWER button turn the set ON.
2. Press the FUNCTION button to select CD.
3. Set Tset mode by momentarlly shorting both side of TEST A.
4. Press the x button two times. The set is into CD test mode.
(88 is displayed)
5. Turn the power off to release test mode.
CONTROL-1 BOARD
(Conductor side)
Focus Bias Check
1. Connect the oscilloscope between TP (RF) and GND on CD
board.
2. Insert the disc (YEDS-18). (Part No. : 3-702-101-01) (CD)
3. Press the u button two times (LPC ON).
4. Confirm that the oscilloscope waveform is as shown in the fig-
ure below. (eye pattern)
A good eye pattern means that the diamond shape (◊) in the cen-
ter of the waveform can be clearly distinguished.
5. Press the u button.(LPC OFF)
6. Perform confirmation in step 4 again.
• RF Signal Reference Waveform (eye pattern)
VOLT/DIV : 200mV
TIME/DIV : 500 nS
TEST mode : momentarily short
RF level
0.83 – 0.87 Vp-p (LPC ON)
0.82 – 0.88 Vp-p (LPC OFF)
When observing the eye pattern, set the oscilloscope for AC range
and raise certical sensitivity.
CD BOARD (Conductor side)
TP (RF)
TP (RF)
(GND)
CFD-G70
oscilloscope
(AC range)
1-68
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