Oscillator Circuit - Elenco Electronics SUPERHET AM-550TK Assembly And Instruction Manual

STATIC MEASUREMENTS
Q1 BIAS
With the power turned OFF, connect the VOM to your
circuit as shown in Figure 19. Connect a clip lead from
test point two (TP2) to the collector of Q1. This short
prevents Q1 from oscillating. Set the VOM to read 2 volts
DC accurately and turn the power ON. The DC voltage
Amps COM V/W
Figure 19
If you do not have an oscilloscope, go to the Final Alignments With No Test Equipment Section.
DYNAMIC MEASUREMENTS

OSCILLATOR CIRCUIT

With the power turned OFF, connect the oscilloscope to
the circuit as shown in Figure 20. Set the oscilloscope
for a vertical sensitivity of 1 volt/division and turn the
power ON. The oscilloscope should display a low
Figure 20
go to the Final Alignments with No Test Equipment Section.
V
GND
R2
If you don't have an oscilloscope and an RF generator,
at TP1 should be 1.6 volts. If the voltage in your circuit
differs by more than 0.5 volts, leave the power ON and
check the battery voltage.
greater than 8.5 volts, turn the power OFF and check
components R1, R2, R3 and Q1.
voltage sine wave. The frequency of the sine wave
should change when capacitor C1 is turned. If your
circuit fails this test, turn the power OFF and check
components Q1, C1, C2, C3, L1 and L2.
Oscilloscope
-26-
If the battery voltage is
Clip Lead
GND
R2