12
DP-IF8000
SECTION 5
ELECTRICAL ADJUSTMENT
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.
TP119,121,125,127,
130,131,133,134
10k
Ω
0.1
µ
digital voltmeter
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.
TP119,121,125,127,
130,131,133,134
oscilloscope
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 :
C301
R111
Q
3
5
5
R
1
0
0
R
1
0
7
R
2
1
0
R215
R
1
0
1
R
1
1
4
C
2
9
0
R
1
1
3
C210
R
2
0
8
R
2
1
Q
3
5
8
R
1
0
2
C
2
0
6
Q
3
5
2
C
2
2
3
C
2
3
0
R
2
1
1
R
2
0
9
R112
Q
3
6
2
Q
3
6
1
Q
3
6
0
C
2
3
9
C241
C231
IC206
JC
1
1
7
C242
Q
3
5
6
Q
3
5
3
Q
3
5
9
R
1
1
0
JW221
D
1
7
JW
2
0
4
D
2
1
JW
2
2
0
JW211
C
3
5
1
0
JW212
JW209
JW218
D
2
2
0
JW227
D
1
3
D
1
4
D
1
5
D
1
6
D
9
D
8
D
7
D
2
0
8
D
2
0
9
D
2
D
D
2
D
2
S
W
3
D221
VERTUAL
TP131
TP130
TP133
TP134
TP127
TP125
TP133
TP131
TP130
TP125
TP127
• Adjustment location:
TX BOARD (SIDE A)
IC12
IC19
RV201: RF LEVEL alignment
RV101: DC BIAS alignment
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