Elenco Electronics AM-550TK Instruction Manual download pdf (Page 27)

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Figure 20

Figure 19

Oscilloscope

Amps COM V/Ω

Clip Lead

GND

STATIC MEASUREMENTS

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

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. If the battery voltage is

greater than 8.5 volts, turn the power OFF and check

components R1, R2, R3 and Q1.

Q1 BIAS

If you do not have an oscilloscope, go to the Final Alignments With No Test Equipment Section.

DYNAMIC MEASUREMENTS

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

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.

OSCILLATOR CIRCUIT

If you don’t have an oscilloscope and an RF generator,

go to the Final Alignments with No Test Equipment Section.

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Elenco Electronics AM-550TK Instruction Manual Page 27