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Static measurements, Assembly instructions – Elenco AM/FM Radio Kit User Manual

Page 25

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STATIC MEASUREMENTS

AGC ZERO SIGNAL BIAS

With the power turned OFF, connect your VOM to TP5 as shown in Figure 23. Make sure that the AM/FM switch
is in the AM position.

Check that the VOM is adjusted to
read 9 volts DC and turn the power
ON. The voltmeter should read
approximately 1.5 volts DC. If your
reading varies by more than 0.5
volts from this value, turn the power
OFF and check the polarity of D4.
Also check R36 and R35 and check
that transformer T6 is properly
installed.

T8 TEST

-24-

ASSEMBLY INSTRUCTIONS

C34 - 100

μ

F Lytic

(see Figure B)

T6 - AM IF Coil

(Yellow Dot)

R35 - 27k

Ω

Resistor

(red-violet-orange-gold)

TP5 - Test Point Pin

(see Figure A)

C32 - 10

μ

F Lytic

(see Figure B)

R36 - 3.3k

Ω

Resistor

(orange-orange-red-gold)

C33 - .02

μ

F Discap (203)

or .022

μ

F Discap (223)

R38 - 100

Ω

Resistor

(brown-black-brown-gold)

TP3 - Test Point Pin

(see Figure A)

T8 - AM IF Coil

(Black Dot)

D4 - 1N4148 Diode

(see Figure H)

C38 - .01

μ

F Discap (103)

R42 - 2.2k

Ω

Resistor

(red-red-red-gold)

If you do not have an RF generator, skip to Section 3.

With the power turned OFF, connect the positive lead
of the VOM to TP3 and the negative lead to ground
pin TP15. Make sure that the VOM is set to read 9
volts DC and turn the power ON. The voltage on the

VOM should be the same as your battery voltage or
power supply voltage. If not, turn the power OFF and
check that T8 is properly installed. Turn the power
OFF.

Figure 23

GND

TP15