Elctorical Ajustment - Sony DP-IF8000 Service Manual

DP-IF8000
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3 7 63 1515 0
1. CAUTION
1. Perform adjustment in sequence as listed.
2. Apply a 9 volt DC supply voltage.
2. DC BIAS ADJUSTMENT
Connect a digital voltmeter to test points TP119, 121, 125, 127,
130, 131, 133, 134 on the LED board. Adjust RV101 on the TX
board to obtain an output voltage of 480 ± 5mV on the TX board.
digital voltmeter
10k Ω
0.1 µ
ceramic
3. RF level alignment
Connect an oscilloscope to test points TP119, 121, 125, 127,
130, 131, 133, 134 on the LED board. Adjust RV201 on the TX
board to obtain an output waveform of 960±5mVp-p.
oscilloscope
TE
L 13942296513
Note: Use an oscilloscope with a bandwidth of at lest 200 MHz.
4. RECHECK
The DC bias adjustment made above in 2. may sometime change
(deviate) after the RF level adjustment is made above in 3. So
recheck that the DC bias is at the correct level after making the
RF level alignment. If the DC bias has deviated, realign by re-
peating the adjustment in 2. and 3. above.
• Connection points :
(pattern)
LED BOARD
TP121
TP121
TP119
TP119
TP134
TP133
TP130
www
TP131
TP131
TP130
.
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SECTION 5
ELECTRICAL ADJUSTMENT
TP119,121,125,127,
130,131,133,134
TP119,121,125,127,
130,131,133,134
TP125
TP125
TP127
TP127
TP134
TP133
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2 9
8
• Adjustment location:
TX BOARD (SIDE A)
IC12
RV101: DC BIAS alignment
Q Q
3 6 7 1 3 1 5
co
.
9 4 2 8
RV201: RF LEVEL alignment
IC19
0 5 8 2 9 9 4 2 8
m
9 9
9 9