HP 209A Service manual

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OPERATING AND SERVICE MANUAL
SINE IS·QUARE
OSCILLATOR
209A
HEWLETT. PACKARD
www.HPARCHIVE.com
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HEWLETT" PACKARD
CE RTI FI CATION
The Hewlett-Packard Company certifies that this instrument was
thoroughly tested and inspected and found to meet its published
specifications when
it was shipped from the factory. The Hewlett-
Packard Company further certifies that its calibration measure-
ments are traceable to the
U.S. National Bureau of Standards to
the extent allowed by the Bureau's calibration facility.
WARRANTY AND ASSISTANCE
All Hewlett-Packard products are warranted against defects in
materials and workmanship. This warranty applies for one year
from the date of delivery, or,
in the case of certain major compo-
nents listed in the operating manual, for the specified period. We
will repair or replace products which prove to be defective during
the warranty period provided they are returned to Hewlett-
Packard. No other warranty is expressed or implied. We are not
liable for consequential damages.
Service contracts or customer assistance agreements are available
for Hewlett-Packard products
that require maintenance and re-
pair on-site.
Forany assistance, contact your nearest Hewlett-Packard Sales and
Service Office. Addresses are provided
at the back of this manual.
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OPERATING AND SERVICE MANUAL
-hp- Part No. 00209-90002
MODEL
SINE/SQUARE
209A
OSCILLATOR
Serials Prefixed: 818-
Copyright Hewlett-Packard Company 1968
P.O. Box 301, Loveland, Colorado, 80537 U.S.A.
www.HPARCHIVE.com
Printed: MAY 1970

Table of Contents
Model209A
TABLE OF CONTENTS
APPENDICES
A. CODE LIST
OF MANUFACTURERS
B. SALES AND SERVICE OFFICES
C. MANUAL BACKDATING CHANGES
Section Page
VI REPLACEABLE PARTS
6-1
6-1. Introduction 6-1
6-4. Ordering Information 6-1
6-6. Non-Listed Parts 6-1
Section Page
VII CIRCUIT DIAGRAMS
7-1
7-1. Introduction 7-1
7-3. Schematic Diagrams 7-1
7-5. Component Location Diagrams 7-1
Page
5-23.
5-26.
5-28.
5-29.
5-30.
Section
VMAINTENANCE
(Cont'd)
5-8. Distortion Check 5-3
5-9.
Output Voltage and Impedance
Check (Sine Wave) 5-4
5-10.
Output Control Check
(Sine Wave) 5-4
5-11. Balance Check (Sine Wave) 5-4
5-12.
Output Voltage Check
(Square Wave) 5-4
5-13. Rise Time Check
(Square Wave) 5-5
5-14.
Symmetry Check
(Square Wave) 5-5
5-15. Sync
Output Check 5-5
5-16.
Sync Input Check 5-5
5
-1 7. Cover Removal . . . . . . . . . . . . . . . . . 5-6
5-22. Adjustment and Calibration
Procedure 5-6
Introduction 5-6
Power Supply 5-6
Bias Adjustment 5-6
AGC Adjustment 5-6
AGC
and Frequency
Adjustment 5-6
5-31. High Frequency Adjustment 5-7
5-32. Distortion Adjustment 5-7
5-33.
Symmetry Adjustment 5-7
5-34.
Factory Selected Components 5-7
5-36. Troubleshooting Procedures 5-8
5-37. Front Panel Procedure 5-8
5-40. Detailed Circuit
Troubleshooting 5-8
Section Page
VMAINTENANCE 5-1
5-1. Introduction
5-1
5-4. Performance Checks 5-1
5-6. Dial Accuracy Check
5-1
5-7. Flatness Check 5-1
Section Page
IGENERAL INFORMATION
1-1
1-1. Introduction 1-1
1-3. Specifications 1-1
1-5. Description 1-1
1-10. Instrument/Manual Identification .. 1-1
Section Page
II INSTALLATION
2-1
2-1. Introduction 2-1
2-3. Initial Inspection 2-1
2-5. Power Requirements 2-1
2-7. Grounding Requirements 2-1
2-10. Installation 2-1
2-12. Bench Mounting 2-1
2-14. Rack Mounting 2-1
2-16. Combination Mounting 2-1
2-18. Repackaging for Shipment 2-1
Section Page
III OPERATING INSTRUCTIONS
3-1
3-1. Introduction 3-1
3-3. Turn On Procedure 3-1
3-5. Operating Considerations 3-1
3-6. Floating Output 3-1
3-8. Balance 3-1
3-10. Synchronization 3-1
3-13.. Low Distortion 3-1
Section Page
IV THEORY
OF OPERATION 4-1
4-1. Introduction 4-1
4-4. Block Diagram Description , 4-1
4-5. Bridge and Amplifier 4-1
4-9. Peak Comparator and AGC _ 4-1
4-13. Buffer Amplifier 4-2
4-15. Sine-Square Converter 4-2
4-17. Detailed Circuit Description 4-2
4-25. Power Supply 4-2
iii
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Model209A
LIST OF TABLES
Table of Contents
Number
Page
1-1. Specifications 1-0
5-1. Required Test Equipment 5-0
5-2. Dial Accuracy Check 5-1
5-3. Flatness Check 5-2
Number
Page
5-4. Distortion Check 5-3
5-5. Factory Selected Components 5-7
5-6. Front Panel Symptoms 5-8
6-1. Replaceable Parts 6-2
LIST OF ILLUSTRATIONS
Number Page
1-1. Model 209A Sine/Square Oscillator 1-1
2-1. Dimensions 2-2
3-1. Description of Controls and Connectors 3-0
4-1. Model209A Block Diagram 4-0
4-2.
RC Frequency Network Characteristics 4-1
5-1. Dial Accuracy Check 5-1
5-2. Flatness Check 5-2
5-3. 2
MHz Distortion Check 5-3
5-4. Balance Check 5-4
5-5. Sync Input Check
5-5
6-1. Front Panel Exploded View 6-4
7-1. Oscillator Schematic
(AI) 7-3/7-4
7-2. Power Supply Schematic (A2) 7-5/7-6
iv
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Section I
-RANGES-
Table 1-1. Specifications
SQUARE
WAVE
Model209A
Frequency: 4
Hz to 2 MHz in 6ranges.
-PERFORMANCE
RATINGS-
Dial Accuracy: +/-3% of frequency setting.
Flatness:
At maximum output into 600 ohm load.
1kHz reference.
Low
Distortion +/-1% +/-0.5% +/-1% +/-5%
Mode
Output Voltage: 20 V pop open circuit
symmetrical about 0
V. Output can be floated
up to +/-500 Vpeak between output and
chassis ground.
Rise and Fall Time:
less than 50 ns.
Symmetry: +/-5%
Output Impedance: 600 to 900 ohms depending
upon setting
of output control.
Normal
Mode
+5%
-1%
+/-0.5% +/-1% +/-5%
(Hz) 4
Distortion:
100 300k
1M
2M -EXTERNAL SYNCHRONIZATION-
Sync Impedance: 10 kilohm.
1.0
-40
\
-- NORMAL MODE
/
*- - - - LOW
D1ST. MODE
I 0.5
/
46
.,
C
i: 0.3
\
50
Q:
I
c
t:; 0.2
V
54
Ci
\
0.1
60
20 60 100 200
FREQUENCY-Hz
20DK 60CK 2M
Sync Output: Sine wave in phase with output;
amplitude working into 1megohm shunted by
100 pF
is greater than 1.7 V rms from 4 Hz to 50
kHz, greater than
.1 Vfrom 50 kHz to 2 MHz.
Sync Input: Oscillator can be synchronized to
external signal. For 5 V rms input, sync
frequency can be
as much as +/-7% away from
set frequency (sync range). Sync range
is alinear
function
of sync voltage.
--
Hum and Noise: less than 0.01% of output.
-OUTPUT
CHARACTERISTICS-
SINE WAVE
Output Voltage: 5 V rms (40 mW) into 600 ohms;
10 Vopen circuit. Output can be floated up
to
+/-500 Vpeak between output and chassis
ground.
Output Impedance: 600 ohms.
Output Control: 20
dB range continuously
adjustable.
Output Balance: greater than 40
dB below 20 kHz.
1-0
-GENERAL-
Operating Temperature: Instrument will operate
within specifications from
0% Cto 55% C.
Storage Temperature: 40% C to +75% C
Power: AC-Line 115V
or 230V +/-10%,48 Hz to
440 Hz.
less than 7 W.
Dimensions:
Refer to Figure 2-1, page 2-2.
Accessories Available: HP
1l075A Instrument Case.
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Model209A
SECTION I
GENERAL INFORMATION
Section I
1-1. INTRODUCTION.
1-2. This section contains general information about
the
-hp- Model 209A Sine/ Square Oscillator.
Throughout this manual the instrument will
be
referred to as the Mode1209A.
1-3. SPECIFICATIONS.
1-4. Table 1-1 lists the specifications for the Model
209A.
1·5. DESCRIPTION.
1-6. The Model 209A is aversatile signal source with
independent sine
wave and square wave outputs at
frequencies from 4
Hz to 2 MHz. The square wave
amplitude is variable to amaximum of 20 volts
peak-to-peak into open circuit. The sine
wave
amplitude is variable to amaximum of 10 volts rms
into open circuit from aconstant 600 ohm source.
When working into a600 ohm load, the maximum
output level
is 5volts rms.
1-7. Balanced output can be obtained by
disconnecting the grounding strap at the rear
of the
instrument. This isolates the chassis from the cabinet
and line ground. The sine
wave output will balance to
greater than 40 dB, at frequencies below 20 kHz,
with the chassis isolated.
1-8. The Model 209A can be synchronized with an
external source. With a 5 volt rms sync input, the
external source may vary
as much as +/-7% in
frequency and the Model 209A will remain
synchronized.
1-9. Async output of 1.7 volts rms is also available
at the same front panel terminal used to accept an
external sync source.
1-10. INSTRUMENT/MANUAL IDENTIFICATION.
1-11. Hewlett-Packard uses atwo-section serial
number. The first section (prefix) identities aseries
of
instruments. The last section (suffix) identifies a
particular instrument within the series.
If aletter is
included with the serial number, it identifies the
country in which the instrument
was manufactured.
If the serial prefix of your instrument differs from
the one on the title
page of this manual, achange
sheet will be supplied to make this manual
compatable with newer instruments or the backdating
information in Appendix C
will adapt this manual to
earlier instruments. All correspondence with
Hewlett-Packard should include the complete serial
number.
Figure
1-1. Model 209ASine/Square Oscillator
1-1
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Model209A
SECTION II
INSTALLATION
Section II
2-1. INTRODUCTION.
2-2. This section contains information and
instructions necessary for installing and shipping the
Model 209ASine/Square Oscillator. Included are
initial inspection procedures, power and grounding
requirements, installation information, and
instructions for repackaging for shipment.
2-3. INITIAL INSPECTION.
2-4. This instrument was carefully inspected both
mechanically and electrically before shipment. It
should be physically free of mars or scratches and in
perfect electrical order upon receipt. To confum this,
the instrument should be inspected for physical
damage that occurred in transit.
If the instrument was
damaged in transit, me aclaim with the carrier. Test
the electrical performance
of the instrument using
Performance Checks outlined in Section V.
If there is
damage or deficiency, see the warranty on the inside
front cover
of this manual.
2-5. POWER REQUIREMENTS.
2-6. The standard Model 209A will operate from any
source
of 115 or 230 volts (+/-10%), at 48 to 440 Hz.
With the instrument disconnected from the ac power
source, move the voltage selector switch (located on
the rear panel) so the designation appearing on the
switch matches the voltage
of the power source to be
used. Power dissipation
is less than 7watts.
2-7. GROUNDING REQUIREMENTS.
2-8. To protect operating personnel, the National
Electrical Manufacturers Associatfon (NEMA)
recommends that the instrument cabinet be
grounded. The standard Model 209A
is equipped with
athree-conductor power cable which, when plugged
in to an appropriate receptacle, grounds the
instrument. The offset pin on the power cable
three-prong connector
is the ground connection.
2-9. To preserve the protection feature when
operating the instrument from atwo-contact outlet,
use athree-prong
to two-prong adapter and connect
the green pigtail on the adapter
to earth ground.
2·10. INSTALLATION.
2-11. The Model 209A is fully transistorized;
therefore, no special cooling
is required. However, the
instrument should not be operated where the ambient
temperature exceeds
55
0C(1310F).
2-12. BENCH MOUNTING.
2-13. The Model 209A is shipped with plastic feet
and tilt stand in place, ready for use
as abench
instrument.
2-14. RACK MOUNTING.
2-15. The Model 209A may be rack mounted by
using an adapter frame (-hp- Part No. 5060-0797).
The adapter frame
is arack frame that accepts any
combination
of -hp- submodular units. It can be rack
mounted only. For additional information, address
inquiries
to your -hp- Sales and Service office. (See
Appendix Bfor office locations.)
2-16. COMBINATION MOUNTING.
2-17. The Model 209Amay be mounted in
combination with other submodular units
by using a
Combining
Case (-hp- Model 1051A or 1052A). The
Combining
Case is afull-module unit which accepts
various combinations
of submodular units. Being a
full-module unit, it can be bench or rack mounted
and
is analogous to any full-module unit.
2-18. REPACKAGING FOR SHIPMENT.
2-19. The following paragraphs contain ageneral
guide for repackaging
of the instrument for shipment.
Refer to Paragraph 2-20
if the original container is to
be used; 2-21 if it is not. If you have any questions,
contact your local -hp- Sales and Service Office. (See
Appendix Bfor office locations.)
2-1
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Section II Model209A
-----NOTE-----
If the instrument is to be shipped
to Hewlett-Packard for service or
repair, attach atag to the
instrument identifying the owner
and indicating the service or repair
to be accomplished; include the
model number and full serial
number of the instrument. In any
correspondence, identify the
instrument by model number and
full serial number.
2-20. If the original container is to be used, proceed
as follows:
a. Place the instrument in the original
container if available. If the original
container is not available, one can be
purchased from your nearest -hp- Sales and
Service Office.
b. Ensure that the container is well sealed with
strong tape or metal bands.
2-21. If the original container is not to be used,
proceed as follows:
a. Wrap the instrument in heavy paper or
plastic before placing it in an inner
container.
b. Place packing material around all sides of the
instrument and protect the panel face with
cardboard strips.
c. Place the instrument and inner container in a
heavy carton or wooden box and seal with
strong tape or metal bands.
d. Mark the shipping container with
"DELICATE INSTRUMENT", "FRAGILE"
etc.
Dimensions:
209A
TOP 8
(203,21
"-----------,,L
~ 5i ('30'21~
~
t
(10.3)
DIMENSIONS IN INCHES AND (MILLIMETERS)
[T
SIDE
6f2
~
(154,e)
~
e"
~
Figure 2-1. Dimensions
2-2
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Section III Model209A
2
SYNC
""""
I "'AX
6000
3
9
10
,",-LINE
SELECTOR
o ~
IIS/230V± 10%
48-440"" TVA MAX
CHANGE
FREQ.
SLOWLY
I
,OW
NORM OISl.
""
~~~
~ ~ ~
CD RANGE Switch: Selects frequency range or
OFF position.
eD Frequency Dial: Selects frequency within
desired range. Dial setting multiplied by
RANGE switch position indicates output
frequency.
oFrequency Vernier: Provides fine tuning of
frequency dial.
oSquare Wave Amplitude Control: Varies
Square
Wave output level to 20 volts
peak-to-peak, open circuit.
eD Sine Wave Amplitude Control: Varies Sine
Wave output level over a20 dB range to 10
volts rms, open circuit (5 volts rms into 600
ohms).
CD Sine Wave Output Terminal: 600 ohm sine
wave output at afrequency and amplitude
determined
by control settings.
CD Square Wave Output Terminal: 600 ohm
square
wave output at afrequency and
amplitude determined by control settings.
CD SYNC Terminal: (1) Input terminal for an
external sync signal. (2) Output terminal for
1.7 volt rms sine
wave sync signal.
CD Ground Strap: Connects the floating circuit
ground to power ground.
®Voltage Selector Switch: Selects line voltage
of 115 volts or 230 volts AC.
® AC Power Receptacle: Mates with power
cord supplied with this instrument for line
voltage connection.
@NORM/LOW DIST. Switch: Selects normal
or low distortion below 100 Hz.
Figure 3-1. Description
of Controls and Connectors
3-0 www.HPARCHIVE.com

Mode1209A
3·1. INTRODUCTION.
SECTION III
OPERATING INSTRUCTIONS
3-8. BALANCE.
Section III
3-2. This section contains information
as an aid to
operating the Model 209A. Included are control and
connector descriptions (Figure 3-1), and some special
operating considerations.
3-3. TURN ON PROCEDURE.
34. To turn on the Model 209A, proceed as follows:
a. Set the two-position voltage selector switch
on the rear panel
to the value of available
line voltage.
b. Connect the
AC power cord to line voltage.
c. Switch the RANGE switch from OFF to the
desired frequency range.
d. Select the desired frequency and voltage
output with the frequency dial and
amplitude controls respectively.
3-5. OPERATING CONSIDERATIONS.
3-6. FLOATING OUTPUT.
WHEN THE GROUND STRAP ON
THE REAR PANEL IS
CONNECTED, INPUT GROUND
IS AT EARTH GROUND
POTENTIAL.
3-7.
When the ground strap on the rear of the Model
209A
is disconnected, the chassis is isolated from
power ground. The outputs may then
be connected
to any point with adc potential
of not more than
+/-500 volts.
If adc voltage up to +/-500 volts is
connected between the ground connectors on the rear
panels, the oscillator output
is dc offset by that
amount.
3-9. With the chassis isolated from the cabinet, the
sine wave output will be balanced to greater than 40
dB at frequencies below 20 kHz. If the square wave
output is being used simultaneously with the black
terminal connected to ground, the sine wave output
will no longer be balanced.
3-10. SYNCHRONIZATION.
3-11. The Model 209A is equipped with a SYNC
terminal that provides async output signal or accepts
asynchronizing input signal from an external source.
The sync output signal
is a1.7 volt rms sine wave in
phase with the oscillator output. The external sync
signal can be any periodic waveform
of sufficient
amplitude to maintain sync. For an external sync
signal with an amplitude
of 5volts rms, the oscillator
will remain synchronized at frequencies
of +/-7% of
the set frequency.
3-12. The Model 209A can be synchronized to any
significant harmonic
of an external signal. However, if
aharmonic or non-sinusoidal waveform is used to
synchronize the Model 209A, some portion of the
external sync signal will be
on the output. This small
signal will appear
as distortion. The amount of this
apparent distortion will be directly proportional
to
the amplitude of the sync signal. For anon-sinusoidal
sync input
of 2volts peak-to-peak, the distortion will
be down about
45 dB for frequencies which are
normally down -60 dB.
3-13. LOW DISTORTION.
3-14. At frequencies below 100 Hz, distortion can be
reduced by switching the NORM/LOW DIST switch
on the rear panel
to LOW DIST. In the LOW DIST
mode
the Model 209A will have alonger settling time
when changing frequencies. To avoid this, set the
desired frequency before switching to
LOW DIST.
3-1
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R24
AGC
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R8
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Model209A Section IV
SECTION IV
THEORY OF OPERATION
4-1. INTRODUCTION.
4-2. This section contains adescription of the basic
principles
of circuit operation for the Model 209A.
The information
is presented as adiscussion of each
block indicated on the Block Diagram, Figure 4-1,
and detailed circuit descriptions which refer to Figure
7-1 and 7-2.
4-3. The Model 209A
is basically a Wien bridge
oscillator. The output from the oscillator circuit
is
applied to abuffer amplifier and to asine wave to
square wave converter. These two circuits provide
independent sine
wave and square wave outputs,
respectively.
4-4. BLOCK DIAGRAM DESCRIPTION.
furnished through the frequency determining
network
of CIA, R8, CIB, and R16. At the
frequency that the phase
of the positive feedback is
00,Xc =Rand the maximum ratio of output
voltage
is supplied to the amplifier (see Figure 4-2).
The characteristics
of the Wien bridge are such that
the output voltage to the +input
of the amplifier at
F0
is one third the amplitude of the positive feedback
voltage. Therefore, to maintain unity gain and
oscillation, the negative feedback network (R28, R24
and AGC) was designed with adivider ratio
of two to
one, to
give the amplifier again of three.
4-8. The amplifier itself
is asolid-state, high gain
amplifier with the output in phase with the input so
that feedback will produce oscillations.
4-9. PEAK COMPARATOR AND AGC.
-RATIO
FREQUENCY
4-5. BRIDGE AND AMPLIFIER. 4-10. The voltage output from the
Wien bridge to the
input
of the amplifier is not always one third of the
positive feedback voltage at
all operating frequencies,
nor
is the amplifier gain constant for all operating
frequencies. One technique used for maintaining
unity gain in the oscillator circuit at
all operating
frequencies
is to have adynamic resistance, variable
with changes in gain, in the negative feedback
network. In the Model 209A this
is accomplished
with the combination
of the peak comparator and
AGC circuits.
4-12. When the oscillator
is first turned on, the AGC
gives the amplifier again of much greater than three.
Noise in the amplifier
is amplified greatly, and the
frequency selective network in the
Wien bridge selects
the noise at the tuned frequency. The selected noise
becomes positive feedback to the amplifier, and the
amplifier starts oscillating at the tuned frequency.
As
the output amplitude approaches 7.2 volts peak, the
4-11. The peak comparator compares the negative
peak
of the oscillator amplifier output to a7.2 volt
reference.
If the output varies above or below the
reference voltage, adifference voltage will be supplied
to the
AGC circuit. The "dynamic resistance" of the
AGe circuit is afield-effect transistor with the gate
controlled
by the difference signal from the peak
comparator. The oscillator amplifier output
is held to
7.2 volts peak amplitude.
LEAD
LAG
-
-/
--
//
.".......-
-.........
//
-/
/
//~
//--
""
--
~//
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----- PHASE
E
pf
sPOSITIVE FEEDBACK VOLTAGE TO AMPLIFIER
Eo "OSCILLATOR CIRCUIT OUTPUT VOLTAGE
F0 " FREQUENCY WHERE Xc 11 R
0.4
o.
Figure 4-2. RC Frequency Network Characteristics
4-6.
An overall loop gain of at least unity is a
requirement for any amplifier to oscillate. The Model
209A satisfies this requirement with acombination
of
positive and negative feedback through the bridge.
4-7. The oscillator bridge
is divided into two
networks, the frequency selective network and the
negative feedback network. Positive feedback
is
4-1
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Section IV
AGC reduces the gain of the amplifier to three; and
stable oscillation
is achieved.
4-13. BUFFER AMPLIFIER.
4-14. The 5volt rms sine wave output from the
oscillator circuit
is coupled to the buffer amplifier.
The amplifier has ahigh open loop gain that
is
controlled by the negative feedback to provide a gain
of 2. This enables the circuit to have very low
distortion characteristics. The buffer amplifier uses a
complementary symmetry transistor pair
to furnish a
10 volt
rms output.
4-15. SINE-SQUARE CONVERTER.
4-16. The 5volt rms sine wave output from the
oscillator circuit
is also applied to the sine-square
converter. The sine
wave is coupled to atunnel diode
which produces asmall square wave output with fast
rise and fall times. This small square wave signal is
then shaped and amplified. It appears at the output as
a 20 volt peak-to-peak square wave.
4-17. DETAILED CIRCUIT DESCRIPTION.
4-18. For the following paragraphs, refer to the
Oscillator Schematic Diagram, Figure
7-1 .
4-19. Transistors
AIQI through AIQ7 make up the
basic oscillator amplifier.
Al QI is an N-channel FET.
AlCRI sets up proper de bias for
Al Q2. Diodes
AICR6, AICR7, AICR8 set up proper bias for
Al
Q4. Capacitor Al C9 is chosen to provide astable
roll
off at high frequencies. Al Q7 is acurrent source
for AIQ3 and AIQ4. AICR4 and AICR5 provide
proper biasing for complementary output transistors
Al
Q5 and AlQ6.
4-20. The positive feedback arm
of the Wien bridge
consists
of tuning capacitors AICIA and AIClB, and
range switching resistors
Al RI through Al RI7.
4-21. The negative feedback arm of the Wien bridge
depends upon the ratio
of the impedance of Al R28
to the total impedance
of Al R23, AlR24, Al R25,
and AlQ8. AlR25 reduces the effect
of the FET
Al
Q8 to increase stability. Al Q8 proVides AGC for
this amplifier by varying impedance
to obtain the
proper negative feedback.
4-2
ModeI209A
4-22. The conduction
of FET Al Q8 is controlled by
the peak detector circuit using AIQ9. AIQ9 conducts
during the most negative portion
of each negative half
cycle, developing anegative charge in
Al C 15 and its
parallel capacitors.
As the amplifier output amplitude
increases, Al
Q9 conducts more and Al C 15 becomes
more negatively charged. This makes the FET input
voltage more negative, increasing its impedance and
increasing the negative feedback
to reduce the output
amplitude
of the amplifier.
4-23. Transistors AIQ13 through
AIQI8 comprise a
buffer amplifier with again
of two. AIQ13 and
AIQI4 form adifferential amplifier. Diodes AICRI8
and Al CRI9 furnish proper biasing for
complementary output transistors
Al QI7 and
Al
QI8. When the output attenuator Al R79 is fully
clockwise, the output amplitude
is greater than 10
volts rms. When the attenuator is fully
counter-clockwise, the output
is attenuated by
greater than 20
dB.
4-24. The Sine-Square Converter circuit includes
Al QlO through Al QI2. This converter circuit
operates
as asaturating amplifier. Tunnel diode
Al CRI2 squares the sine wave input, and the
Symmetry Adjust
Al R45 determine the level where
conduction starts. This provides for adjustment
of the
symmetry
of the square wave. Zener diode Al CRI5
sets the voltage level
of the negative portion of the
square wave.
Al QI2 furnishes the positive portion of
the square wave output, and Al QII furnishes the
negative output.
4-25. POWER SUPPLY.
4-26. The following paragraphs refer to the Power
Supply Schematic, Figure 7-2.
4-27. This power supply
is aseries regulated power
supply furnishing
+21 volts and -21 volts. Zener diode
A2CR6 serves
as areference for the positive power
supply, which in turn serves
as the reference for the
negative supply. The positive supply
is described here,
and the negative supply operates similarly.
4-28. Transistor A2QI regulates the output voltage
and
is controlled by A2Q3. A2Q2 is acurrent source
for A2Q3. Zener diode A2CR5 furnishes bias for
A2Q2, while A2R2 injects negative ripple feedback.
A2CR6 sets the emitter voltage
of A2Q3, setting up a
reference for the supply output. A2Q4 current limits
the output
to prevent damage to the supply.
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Section V
Table 5-1. Required Test Equipment
Model209A
INSTRUMENT REQUIRED RECOMMENDED MODEL
SPECIFICA
nONS
Frequency Accuracy:
+/-1 count -hp- Model 5233L
Counter Range: 4Hz
to 2 MHz
AC Voltmeter Range: 10 Hz
to 2 MHz -hp- Model 400E
Sensitivity: 1mV
to 10 V
Accuracy: +/-2%
DC Null Sensitivity: 10
uV to 20 V-hp- Model 419A
Voltmeter Accuracy: +/-2%
of full scale
Distortion Range: 5
Hz to 600 kHz -hp- Model 334A
Analyzer Fundamental Rejection:
greater than 60
dB
Test Range: 10 Hz to 2 MHz -hp- Model 651 B
Oscillator Output: 5 V rms open circuit
Oscilloscope Frequency Range: 4Hz to -hp- Model 140A
20
MHz (plug-ins) 1402A
Sweep Speed: 50 nsec/cm
l420A
Thermal Accuracy: +/-0.2% -hp- Model H08-11049A
Converter Frequency Range: 5Hz
to 2 MHz
Voltage Input: 5 V rms
Input Impedance: 600 ohms
Bucking See Figure 5-2 for diagram
Supply
a. R: fxd 6500 ohms -hp- Part No. 0811-0392
b. R: var 500 ohms -hp- Part No. 2100-0324
c. R: var 50 ohms -hp- Part No. 2100-1481
d. Battery: 1.34 VMallory RM-42R
2
MHz Notch See Figure 5-3 for diagram
Filter
a. C: fxd 30 pF
-hp- Part No. 0160-0181
b.
C: fxd 400 pF (2) -hp- Part No. 0150-0071
c. L: fxd 30 uH -hp- Part No. 9100-1624
d. R: fxd 1kilohm -hp- Part No. 0686-1025
e. R: fxd 82 kilohms -hp- Part No. 0686-8235
f. R: var 10 kilohms -hp- Part No. 2100-1776
Balance See Figure 5-4 for diagram
Network
a. R: fxd 300 ohms +/-0.1% -hp- Part No. 0811-0029
b. R: fxd 150 ohms +/-1% -hp- Part No. 0757-0715
Terminating R: fxd 600 ohms +/-1% -hp- Part No. 0757-1100
Resistance
Capacitor
C: fxd 100 pF +/-10% -hp- Part No. 0150-0073
5-0
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Model209A
SECTION V
MAINTENANCE
5-1. INTRODUCTION.
Table 5-2. Dial Accuracy Check
Section V
5-2. This section contains information necessary for
the maintenance
of the Model 209A Sine/Square
o scilla tor. Included are performance checks,
adjustment and calibration procedures, and
troubleshooting procedures.
5-3. The test equipment needed to properly maintain
and service the Model 209A
is listed in Table 5-1. If
the recommended model is not available, other
equipment may be substituted provided it meets the
required specifications.
5·4. PERFORMANCE CHECKS.
5-5. The performance checks presented in this
section are designed to compare the Model 209A with
its published specifications. These checks can be used
for incoming inspection, periodic maintenance
checks, and to verify performance after adjustment or
repair. Aperformance check test card appears at the
end
of this section which can be used to record the
performance specifications.
5-6. DIAL ACCURACY CHECK.
a. Connect the Model 209A and the Frequency
Counter
as shown in Figure 5-1. Set the
counter to measure frequency and check the
Model 209A at the frequencies listed in
Table 5-2 for the tolerances indicated.
b.
If the above dial accuracy checks fail to
meet the required specifications, refer to the
Adjustment and Calibration Procedure in
this section.
RANGE FREQUENCY COUNTER
SWITCH DIAL INDICATION
X2 2 4
Hz +/-0.1 Hz
X2 510
Hz +/-0.3 Hz
X2 20
40 Hz +/-1.2 Hz
X10 220 Hz +/-0.6
Hz
X10 550
Hz +/-1.5 Hz
XlO 20 200
Hz +/-6 Hz
XlOO 2200 Hz +/-6 Hz
X100 5500
Hz +/-15 Hz
XlOO 20 2kHz +/-60 Hz
X1K 2 2 kHz +/-60
Hz
X1K 5 5 kHz +/-150 Hz
X1K 20 20 kHz +/-600 Hz
XlOK 220 kHz +/-600
Hz
X10K 550 kHz +/-1.5 kHz
X10K 20 200 kHz +/-6 kHz
XlOOK 2200 kHz +/-6 kHz
XlOOK 5500 kHz +/-15 kHz
X100K 20 2
MHz +/-60 kHz
5-7. FLATNESS CHECK.
a. Connect the equipment as shown in Figure
5-2.
-----NOTE-----
The BUCKING SUPPLY should be
constructed from the components
listed in Table 5-1. The 500 ohm
control should be used
as acoarse
adjust and the 50 ohm control
should be used
as afine adjust
hp 209A
OSCILLATOR
@ELECTRONIC COUNTER
hp5233L
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Figure 5-1. Dial Accuracy Check
www.HPARCHIVE.com
5-1

PERFORMANCE CHECK TEST CARO (Cont'd)
DESCRIPTION CHECK
Distortion:
Range Dial NORM LOWDIST
--
X2 2.5 -40
dB
-54 dB
X2 10 -40
dB
-54 dB
XlO 2-40 dB
-54 dB
XlO 10 -54
dB
X100 2-60 dB
XI00
10 -60 dB
XIK 2-60 dB
XIK 10 -60 dB
X10K 2-60 dB
XI0K
10 -60 dB
XIOOK 2-60 dB
XI00K
6-50 dB
XI00K
20 -40 dB
Output Voltage and Impedance
(Sine Wave):
No load 10
Vrms
600 ohm load 5
Vrms
Output Control (Sine Wave):
<1 Vrrns
Balance (Sine Wave): -40
dB
Output Voltage (Square Wave): 20 Vpk-pk
Rise and Fall Time (Square Wave): 50 nsec
Symmetry (Square Wave): +/-0.5 cm
Sync Output: 1.7 V
rms
Sync Input: <18.6 kHz >21.4 kHz
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DC NULL
VOLTMETER
hp 419A
Section V
@
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209A-B-I662
THERMAL
CONVERTER
hp H08-II049A
BUCKING SUPPLY
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Mode1209A
Figure 5-2. Flatness Check
b. Set the Model 209A RANGE switch to
XlOO and the frequency dial to 10. Set the
AMPLITUDE control to maximum output.
c. Adjust the BUCKING SUPPLY 50 ohm fine
control for minimum resistance, and record
the THERMAL CONVERTER output
as
indicated on the DC NULL VOLTMETER.
the
DC NULL VOLTMETER indication by
the THERMAL CONVERTER output
voltage recorded in step c
of this paragraph.
Multiply this value by 100
to get percent of
output change. Divide this percentage by the
THERMAL CONVERTER multiplier to
obtain apercentage within the tolerances
listed in Table 5-3.
d. Adjust the BUCKING SUPPLY coarse and
fine controls for a
OV indication on the DC
NULL VOLTMETER. Do not readjust the
BUCKING SUPPLY controls for the
remainder
of this check.
e. Check the Model 209A flatness at the
frequencies listed in Table 5-3, recording the
DC NULL VOLTMETER indication for each
frequency.
Example:
Frequency
THERMAL CONVERTER output
DC NULL VOLTMETER reading
Calibration Report multiplier
Table
5-3 tolerance
.025 mV x100% =0.29%
5mV x1.7
100 kHz
5mV
25 uV
1.7
+/-0.5%
5-2
NOTE
The THERMAL CONVERTER
is
considered asquare-law device.
Therefore, theoretically, the
percent
of change at the output of
the THERMAL CONVERTER
should be 2times the percent
of
change at the input. Actually the
value
is not quite 2. The number is
typically 1.7. The multiplier (M)
can be determined by measuring
the output (Ei) for a
given input,
doubling the input and again
measuring the output (EF). The
multiplier
is then determined by
the following formula:
M=EF/2Ei
f. Convert each reading on the DC NULL
VOLTMETER
to the percentages listed in
Table 5-3 by the following procedure. Divide
Table 5-3. Flatness Check
Frequency
Toleran~e
Dial RANGE
NORM
LOW
Setting Setting
mST.
2.5 X2
+5% -1% +/-1%
10
X2 +5% -1% +/-1%
2.5 X10
+5% -1% +/-1%
10 X10 +/-0.5%
2.5 X100 +/-0.5%
10 X100 SET
2.5
XlK
+/-0.5%
10 X1K +/-0.5%
2.5 XlOK +/-0.5%
10 XlOK +/-0.5%
3
XlOOK
+/-0.5%
10 X100K
+/-1 %
20 X100K +/-5%
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Mode1209A Section V
hp209A AC VOLTMETER
OSCILLATOR
hp 400E
@
2MHz NOTCH FILTER
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209A-B-I663
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a. Connect the Model 209A sine wave output
with a600 ohm load to the Distortion
Analyzer.
5-8. DISTORTION CHECK.
Figure 5-3. 2 MHz Distortion Check
h. Repeat steps athrough f
of this paragraph
for
all frequencies listed in Table 54.
i. Connect the equipment as shown in Figure
5-3.
b. Set the Model 209A controls
as follows:
Dial .10
RANGE X100
Amplitude Full
CW
NORM/LOW DIST NORM
c. Set the Distortion Analyzer controls
as
follows:
Dial 10
FREQUENCY RANGE X100
METER RANGE 0
dB
FUNCTION SET LEVEL
SENSITIVITY
MIN
MODE MANUAL
d. Inc rease the Distortion Analyzer
SENSITIVITY to obtain a 0 dB indication
on the meter.
e. Switch the Distortion Analyzer FUNCTION
to DISTORTION, and adjust the Distortion
Analyzer dial and BALANCE controls for a
null indication on the meter.
f. When an approximate null has been obtained
with the Distortion Analyzer dial and
BALANCE controls, switch the
MODE to
AUTOMATIC for minimum meter
indication.
g. Meter indication should be greater than 60
dB down from the 0 dB reference.
j. Set the Model 209A frequency dial
to 20
and the RANGE switch
to X1K. Adjust the
sine wave amplitude control for a 0
dB
indication on the AC Voltmeter.
k. Switch
to the X100K RANGE, and adjust
the frequency dial and notch filter control
for aminimum indication on the
AC
Voltmeter.
1. The meter indication should be greater than
40 dB down from the 0 dB reference.
Table 5-4. Distortion Check
Frequency Tolerance
Dial RANGE
LOW
Setting Setting NORM DIST.
2.5 X2 -40
dB
-54 dB
10 X2 -40
dB
-54 dB
2X10
40 dB
-54 dB
10 X10 -54
dB
2X100 -60
dB
10 X100 -60
dB
2X1K -60
dB
10 X1K -60
dB
2X10K -60
dB
10 X10K
-60 dB
2X100K -60
dB
6X100K -50
dB
5·3
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