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CHANGING LIMITER RELEASE TIME TO ONE SECOND
Remove resistor R741 (about 15 mm behind ribbon cable
assembly W813).
CHANGING LIMITER THRESHOLD PRESETS
1. Select the equivalent resistor values for the desired limiter
thresholds from the following table. Then fill in the following
work sheet with the resistor selections.
2. Remove resistors R721, R731, R732, R733, R734 and R735
(surrounding IC U704).
3. Locate empty pads X732, X733, X734 and X735 (surrounding
IC U704).
4. Select a 1/4 W, 1% resistor closest in value to R1 (from the
work sheet), and solder it to the holes of X732.
Note: Use parallel or series combinations of resistors to match
the chosen values as closely as possible if 1% resistors are not
available.
5. Calculate resistor R5 value as follows:
Select a 1/4 W, 1% resistor closest in value to R5 and solder it
to the holes of X733.
6. Calculate resistor R6 value as follows:
Select a 1/4 W, 1% resistor closest in value to R6 and solder it
to the holes of X734.
7. Calculate resistor R7 value as follows:
Select a 1/4 W, 1% resistor closest in value to R7 and solder it
to the holes of X735. (See Changing Limiter Threshold Presets:
Samples Calculations later in the Appendix for an example of
limiter threshold preset component calculations.)
CHANGING LIMITER THRESHOLD PRESETS: SAMPLES
CALCULATIONS
For the following limiter thresholds:
1. Obtain a 105 kΩ, 1/4 W, 1% resistor and solder it to the holes
of X732.
2. Obtain a 150 kΩ, 1/4 W, 1% resistor and solder it to the holes
of X733.
3. Obtain a 52.3 kΩ, 1/4 W, 1% resistor and solder it to the holes
of X734.
4. Obtain a 49.9 kΩ, 1/4 W, 1% resistor and solder it to the holes
of X735.
Limiter Threshold
(dBm into 600 Ω)
R
equiv
(kΩ)
Limiter Threshold (
dBm into 600 Ω)
R
equiv
(kΩ)
0181081
1211193
2 25 12 105
3 30 13 122
4 35 14 139
5 41 15 156
6 47 16 175
7 54 17 194
8 62 18 215
971
DIP Switch S701 Limiter Threshold
R
equiv
(above)
Position 2 Position 3
–
dBm
–
up up high _____ kΩ = R1
down up med. high _____ kΩ = R2
up down med. low _____ kΩ = R3
down down low _____ kΩ = R4
R5 =
1
R2
–
1
R1
1
DIP Switch S701 Limiter Threshold R
equiv
Position
2
Position
3
–
dBm
–
up up high 12 105
kΩ=R1
down up med. high 8
62 kΩ=R2
up down med. low 4
35 kΩ=R3
down down low 0
18 kΩ=R4
R6 =
1
R3
–
1
R1
1
R7 =
1
R4
–
1
R1
1
1
R5
–
1
R6
–
1
1
1
105,000
R
5=
= 151.4 k:
62,000
= 52.5 k:
1
1
1
R
6=
35,000
105,000
1
11
= 49.4 k:
R
7=
1
150,000
1
52,30018,000
105,000