Heathkit IG 5280 Manual

Page 1

RF OSCILLATOR
Model lG-5280

595-1957-04

Copyrlghl © 1971

Heath Company

H EAT H C O M PA N Y All Rights Reserved
BENTON HARBOR, MICHIGAN 4902 2

Primed in the Unixed States at America

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_I-IEATHKIT@
TABLE OF CONTENTS
Introduction ................................. 2 Applications ................................ 29
Parts List .................................... 3 In Case of Difficulty .......................... 31
Troubleshooting Chart .................... 32
Assembly Notes ............................... 6 -

Specifications ............................... 33

Step-by-Step Assembly ........................ 9
Circuit Board Assembly ............ 9 Circuit Description ........................... 34

Chassis Assembly .......................... 14
Power Supply Switch and Circuit Board X-Ray View .................... 35

Connector Wiring .......................... 20
Knob and Dial Pointer Semiconductor Identification Chart ............ 36

Installation ................................ 22

Checkout .................................. 23
Adjustments and Calibration .................. 24 Schematic .......... (Illustration Booklet, Page 7)
Final Assembly .............................. 27 Warranty ..................... Inside Front Cover
Operation ................................... 28 Customer Service .............. Inside Rear Cover

INTRODUCTION

The Heathkit Model IG-5280 Portable RF Oscillator
provides AM modulated or unanodulated RF (radio
frequency] signals. Five overlapping bands provide a
wide range of frequencies covering the AM, FM, TV,
LW, and SW broadcast bands. RF frequency is indi-
cated on a large, easy-toqead dial scale. A continu-
ously variable attenuator provides output signal
levels that are suitable for most applications. A built-
in 1000 Hz oscillator provides modulation for the RF
signal and serves as a convenient source of audio
signal.

To insure greater accuracy of the RF frequencies, the
bandswitch and coil assembly has been assembled
and adjusted at the factory. The completed RF Oscil-
lator can be calibrated with a voltmeter and an
AM-FM receiver.

This RF Oscillator is housed in the 5280-series in-
strument cabinet. This cabinet has a convenient stor-
age compartment and is stackable. This will help you
to lay out a neat test center" arrangement. Each kit in
this series is designed to operate from batteries as well
as from an optional AC power supply.

The type 5280 series includes the Model IM-5284
Multimeter, the Model IPA-5280-1 Power Supply,
and several other kits. If you have purchased the Mul-
timeter, you may want to build it first so that it is
available to check the other kits as you assemble
them. You may want to build the power supply next
to avoid the need for batteries.

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632 X 1/4"

PICTORIAL 13

Refer to Pictorial 13 for the following steps.

( ) P1: Bend the ears of the connector shell back
against the side of the body as shown. Position
the pointed end as shown. Push the connector
shell into the mounting plate hole at P1. The
ears of the connector shell will lock into place at
the edges of the hole.

( ] SW4: Install the switch on the mounting plate
with two 6-32 X 1/4 screws. Be sure to position
the switch lugs as shown.

KNOB AND DIAL POINTER INSTALLATION
Refer to Pictorial 14 for the following steps.

[ ) Refer to Detail 14A and locate the dial pointer
and an 8-32 x 1/8" setscrewi Start the setscrew
into the dial pointer collar.

[ ) Slide the dial pointer onto the tuning capacitor
shaft. Loosen the tuning capacitor hardware
which holds it to the chassis and adjust the
capacitor and/or sheet metal to center the dial
pointer in the hole. Retighten the hardware.

NOTE: In the following steps, the dial pointer must be
positioned so that it will move an equal distance past
the dial scale at both ends.

-HEATHKIT®

MOUNTING

PLATE
\ \ /

CONNECTOIt

(

SHELL WITH

( ) Make sure the tuning capacitor shaft is fully

]

counterclockwise. and position the dial pointer
black line a little below the left end of the dial
scale. Lightly tighten the setscrew.

g 8-32 X 1/8"
I SETSCREW

DIAL POINTER

% Detail 14A
832 x 7/16"
SETSCREW

Turn the capacitor fully clockwise and see if the
pointer line is the same distance past the dial
scale as you set it at the other end. Adjust it as
necessary and tighten the setscrew.

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-HEATI-Ixz're

ADJUSTMENTS AND CALIBRATION

In the following steps, if you do not get the indicated
results, turn the Oscillator off and refer to the In Case
of Difficulty" section.

Refer to Pictorial 15 [Illustration Booklet, Page 4) and
study the operation of each switch and control of the
RF Oscillator. Note the location of the AMPL ADI
control (R5), BIAS ADI control (R19), and trimmer
capacitors C12 and C22 on the circuit board.

POWER SUPPLY CONNECTION

Perform this step only if you are going to use batteries.

( ) Connect the two 9-volt batteries, which you
purchased earlier, to the battery connectors. If
you wired the power supply switch, place this
switch in the Batt position.

NOTE: If you are using battery power ONLY, disre-
gard the following steps and proceed to Oscillator
Amplitude Adjustment.

( ) Connect one of the five connector shells coming
from the Power Supply to P1 on the mounting
plate. Make sure the wire colors at both connec-
tors are the same and are not reversed. See the
inset drawing #1.

[ ) Place the LINE/BATT switch to the LINE posi
tion.

( ) Plug the Power Supply line cord into the ap-
propriate AC receptacle.

OSCILLATOR AMPLITUDE ADIUSTMENT

( ] Place the AF OFF/ON switch in the ON posi»
tion.

( ) Connect a DC voltmeter to the base of Q3 and set
the BIAS AD] control to read 4.3 volts on the
meter.

( ) Disconnect the DC voltmeter.

( ) Place the AF OFF/ON switch in the OFF posi-
tion.

NOTE: You will need a voltmeter capable of measur-
ing AC for the following steps.

[ ) Set the meter to the lowest range capable of
measuring 2 volts AC.

( ] Place the AF OFF/ON switch in the ON posi-
tion.

( ] Turn the AF AMPLITUDE control to the
maximum clockwise position.

( ) Connect an AC voltmeter to the emitter of Q3
and set the AMP/AD] control to measure 2 volts
rms on the meter.

( ) Disconnect the AC voltmeter.

PRESET ADJUSTMENTS

The coil slug adjustment which determines the lower
end frequency of each band, has been adjusted to
precision standards at the factory.

The trimmer capacitors adjust the high end fre-
quency. When you preset these in the next two steps,
the RF Oscillator will be reasonably close to the final
calibration.

[ ) Refer to Pictorial 15 and preset trimmer
capacitor C12 as follows: Turn the screw down
until it is snug; then turn it counterclockwise
1-1/2 turns.

( ] Adjust trimmer C22 to the position shown in
Pictorial 15.

NOTE: Two calibration methods are provided for
greater accuracy. A frequency counter provides the
most accurate and quickest method of calibration. If
you have a frequency counter, disregard the Radio
Calibration steps below and follow the steps under
Frequency Counter Calibration" on Page 26. If you
do not have a frequency counter, you may use a radio.
Follow the steps under Radio Calibration.

RADIO CALIBRATION
Bands A through D

[ ] Turn the RF Oscillator and AM-FM radio on.
Allow the Oscillator and radio to warm up for
15 minutes so all components will reach normal
operating temperature.

[ ] Connect the test leads to the RF OUTPUT jacks.

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-HEATHKITe g

CIRCUIT BOARD X-RAY VIEW

NOTE: To find the PART NUMBER of a component B. Locate this same number in the Circuit
for the purpose of ordering a replacement part: Component Number column of the Parts
List in the front of this Manual.

A. Find the circuit component number (R5, C.

Adjacent to the circuit component number,
C3, etc.) on the X-Ray View.

you will find the PART NUMBER and DE-
SCRIPTION which must be supplied when
you order a replacement part.

VIEWED FROM COMPONENT SIDE