Fisher CR-5125 - Page 16

TRANSISTER ADJUSTMENT
TRANSMITTED FREQUENCY ADJUSTMENT
1. Connect a frequency counter through a 47 k-ohm resistor to
the emitter of Transistor Q2 as illustrated.
Frequency Counter
570 Hz (+3 Hz)
4. Adjust the potentiometer (P3) to obtain 38 kHz (+0.2 kHz)
on the frequency counter. Then, turn the core of the
transformer (T1) until the wave form becomes the
maximum at peak-to-peak (50 — 55 V) on the synchroscope
(Volt. Range: 10V/cm.).
5. Check to see that the frequency counter reads 38 kHz
(£0.2 kHz).
* If not, repeat the adjustment in Item 3 until the specified
value is obtained.
6. Connect the synchroscope (Volt. Range: 0.2V/cm) to the
plus side of Capacitor C6 as illustrated. Then, adjust the
potentiometer (P2) until the synchroscope reading becomes
1 V at peak-to-peak.
Synchroscope §
1V ‘
—16—
2. Turn the potentiometer (P2) fully counter-clockwise and
adjust the potentiometer (P1) by turning it until the
oscillation frequency becomes 570Hz (+3Hz) on the
frequency counter.
3. Connect the frequency counter through a 47 k-ohm resistor
and a synchroscope to the transmitter output as illustrated.
Synchroscope
50 — 55V
Frequency Counter
38 kHz (40.2 kHz)
Resistor
) (47 k-ohm)
Output
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