Electro-Metrics EM-2115, Instruction Manual

Page: 96 / 278

EM-2115 4.0 SERVICE, MAINTENANCE, CALIBRATION
(EM2115S4-28)
Step c-2 for RF Frequency Ranges 1-10 using the information in Table 4.4 (RF
Frequency Ranges 1-10 only).
f. Remove the subminiature coaxial cable from A1A3-J5 (Divide By 100 Input) on
the Microprocessor Board (A1A3) and using an external Signal Generator, repeat
Step c-2 for RF Frequency Ranges 11-15 using the information in Table 4.5 (RF
Frequency Ranges 11-15 only).
g. If the Frequency Display readings are correct in Steps e and f, the following can
be inferred:
1) The Prescaler Module (A12) is defective,
2) The cabling between A12-J2/A1A3-J6 or A12-J3/A1A3-J5 may be defective.
h. If the Frequency Display readings are in error or not present in Steps e and/or f,
the Microprocessor Board A1A3 may be at fault.
Table 4.5
Microprocessor Board A1A3-J5 (Divide By 100)
Frequency Display Preset/Lo Input Data
RF FREQ.
RANGE FREQUENCY
DISPLAY
PRESET
NUMBER
LO
FREQUENCY
INPUT
(MHz) LO
FREQUENCY
INPUT LEV-
EL
[dB(µV)] FRONT PANEL
FREQUENCY
DISPLAY
READING
(MHz)
11 991.300 0.387 +95.0 30.0000
12 991.300 0.787 +95.0 70.0000
13 9611.30 1.887 +95.0 150.000
14 9931.30 4.187 +95.0 350.000
15 9901.30 8.487 +100.0 750.000
4.4.11 RF Tuner A2 Adjustment/Verification
Equipment required: Signal Generator
Oscilloscope
Spectrum Analyzer
a. Remove the RF Tuner Module A2 from the receiver (Section 4.2.2). Next, remove
the top cover from the RF Tuner (Section 4.2.2.1).