Section V Models 78100A, 78101A
Maintenance
5-39. Transmitter exchange boards will not have the trans- Log Ref Level - 10 dBm
mitter oscillator crystal (Y 1) installed. Remove crystal from Display Adjust - Fully CCW
defective transmitter P.C. board and install it in the ex- Video Filter - Off
change board. A list of carrier frequencies, crystal frequen- Scan Mode - Int
cies and respective crystal part numbers is supplied in Scan Trigger - Auto
Table 5-6 under the applicable channel and option number.
HP 1740A OSCILLOSCOPE
5-40. Test Equipment Setup.
Position controls during test as required.
541. Test equipment is set up in the following manner for
a11 transmitter testing. Switch names appear at the left, HP 432A POWER METER (With HP 478 Thermistor
under each instrument name, and switch positions are at Mount)
the right.
Mount resistance to 200
8901A MODULATION ANALYZER Calibration Factor to 100
Range to 3 mW
Automatic Operation
Measurement - FM or FREQ as required during test 5300B/5306A MU LTIMETER/COUNTER IN
Low Pass Filter - 3 kHz MAINFRAME
Detector -Peak +, Peak- - as required during test
Resolution - 10 Hz as required during test (see Special Function - FREQ
Functions for the 8901A) Range - 10 kHz
141s SPECTRUM ANALYZER DISPLAY SECTION 5-42. Subcarrier Frequency.
View/Store/Wri te/Erase - Select Write 5-43. This procedure is used to adjust the nominally
\
Focus - Adjust as required 1000 Hz subcarrier frequency. R23 controls the currents
Pergistence - Adjust as required flowing in Q12 and Q13, which controls the charging times
Intensity - Adjust as required without causing trace to of capacitors C8 and C11 in the subcarrier oscillator. R23
bloom is adjusted to produce a 1 kHz subcarrier frequency, which
is monitored by the 5306A Counter.
(IF 141T DISPLAY SECTION IS USED)
a. Prepare transmitter by removing sealed cover (Para-
Storage - STD Position graph 5-21). Install battery into transmitter and mate trans-
Time - Minimum Position mitter to test box 0078063030 plug (Figure 5-12).
Persistence - As required (usually close to minimum)
Intensity - As required without causing trace to bloom b. Attach clip leads from 5306A Counter input to trans-
Focus - As required mitter TP8 (Figure 5-13, Figure 5-14).
8554L SPECTRUM ANALYZER RF SECTION c. Adjust R23 on transmitter P.C. board for 1 kHz
?lo Hz.
Tuning Stabilizer - ON (up position)
Bandwidth - 300 kHz d. Remove clip leads from TP8 and replace tuning cover.
Scan Width - 100 MHz
Scan Width (Per Division) - ?0-1250 MHz? 5-44. Carrier Output.
Input Atten. - 10 dB
Freq. (Fine Tune) - During test as required 5-45. The following sequence of adjustments assures that
Freq. - Approximately 470 MHz the carrier frequency emission will comply with FCC regu-
lations.
8552A SPECTRUM ANALYZER IF SECTION
546. The adjustment of C25 tunes the collector tank cir-
Base Line Clipper - Adjust as required with 141s cuit of Q21, which is the oscillator transistor, so that the
Intensity Persistence to eliminate bloom oscillator turns on. Adjusting C28 in the transistor fre-
Scan Time (Per Division) - 5 ms quency doubler permits selection and amplification of the
LoglLinear Select - Log crystal oscillator second harmonic.
5-1 8 078 100-2 |
ACEC
