Radio Shack PRO-60 Service Manual page 11

Reference Frequency Osc. Alignment
Control Setting
Test Instrument Connection
Adjust Result
OFF/VOLUME control: ON.
SQUELCH control: CCW.
Select channel 1.
Connect the frequency counter
to TP101. See Figure 4.
TCI 02
Adjust TCI 02 so the frequency
is 1123.200000 MHz ± 200 Hz.
Unit °-
TP101
Frequency Counter
Under Test
.
1
Figure 4
Note:
If no frequency counters capable of measuring 1200 MHz are available, use a frequency counter capable of
measuring 20 MHz. Follow the instructions below so the frequency counter can do an appropriate adjustment.
1. The frequency counter for measurement should be accurate within 1 Hz.
2. Be sure a 2 pF capacitor is connected to the end of the cable of the signal line. The unit would be destroyed if
you did not use this capacitor.
If a capacitor other than the 2 pF capacitor is used, or if the capacitor is connected anywhere other than the
end of the measurement cable, correct measurement will never be obtained because of the effects on the oscil¬
lator.
3. Be sure the coaxial cable for measurement is as short as possible (shorter than 1 meter) to avoid stray capaci¬
tance effects.
4. Test point locations and adjustment frequency range are as follows:
Pin 15 of IC101 and Cl 88 (10 pF) are connected to a through hole, as shown in "Alignment and Test Points "
(Page 9). Connect a 2 pF capacitor at a through hole pattern location and then adjust TCI 02 so that the frequency
range is 12.799937 MHz ±2 Hz.
Figure 5
NFM/AM Discriminator Coil Alignment
Control Setting
Test Instrument Connection
Adjust Result
OFFA/OLUME control: ON.
SQUELCH control: CCW.
Select channel 1.
Connect the signal generator
to the Ant. connector and the
DC SSVM to TP301.
See Figure 6.
T301 Set the signal generator
frequency to 512 MHz, 100 pV
output (no mod.), and adjust
T301 to 1+0.1 volt on the DC
SSVM.
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