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O~.RATING

INSTRUCTIONS

Hammarlund Manufaduring Company

A Giannini Scientific Co.

73-88 HAMMARLUND DRIVE

MARS HILL. NORTH CAROLINA

9001-06-00005

THE HQ-IOOA SERIES

COMMUNICATIONS

RECEIVERS

INSTRUCTION AND SERVICE INFORMATION

ESTABUSHED 19]0

ISSUE 3

1r1 order to receive the full unconditional gO-day warranty against defective material arJd workmanship in this receiver, the warranty card must be filled out and mailed within two weeks of purchase.

Please refer to serial number of warranty in correspondence.

THE HAMMARLUND MANUFACTURING CO.

73-88 Harnrnarlund Drive

Mars Hill, North Carolina 28754

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Symbol

VI

V2

V3

V4A

V4B

V5 v6

V7

V8

V9

CRI

CR2

Figure I. Tbe HQ·IOOA Receiver

Type

6BZ6

6BE6

6C4

1!212AX7

1!212AX7

6BA6

6BA6

6BV8

6AQ5

OB2

Cer 72c

Cer 72c

TUBE AND DIODE COMPLEMENT

Tube

Pentode

Pentagrid Converter

Triode

Triode

Triode

Remote Cutoff Pentode

Remote Cutoff Pentode

Twin Diode, Triode

Beam Power Amplifier

Gas Filled Diode

Diode, Silicon

Diode, Silicon

Function

RF Amplifier

Mixer

HF Os cillator

First AF Amplifier

Q-Multiplier

First IF Amplifier

Second IF Amplifier

Detector, Serie s Nois e Limiter, BFO

Audio Power Output

Voltage Regulator

Rectifier

Rectifier

INTRODUCTION

The Hammarlund HQ-l OOA is an all-new communications receive r representing entirely new concepts in electrical and mechanical design.

It will provide years of top performance with minimum maintenance.

The HQ-100A series receivers have a self-contained power supply and a universal transformer capable of operation from a 117 volt 60 cp/s or 220/230 volt 50/60 cp/s source, provided the proper adapter plug

(P2) is installed.

The HQ-lOOA is a superheterodyne receiver with a frequency cover­ age continuously tunable from 540 KCS to 30 MCS with extremely fine control in separation of crowded signals. A very high signal-to-noise ratio plus the famous Hammarlund noise limiter circuit, permits full use of the receiver's excellent sensitivity on the weakest signals. A

Q-Multiplier is provided for varying the selectivity of the receiver.

Red segments on the main tuning dial indicate wherein the majority of the international short wave stations can be located.

Electrical band spread tuning is provided with direct calibration eve ry

10 KCS on 80, 40, and 20 meter bands; every 20 KCS on the 15 meter band and every 50 KCS on the 10 meter band. In addition, an arbitrary band spread logging scale is provided for use throughout the tuning range of the receiver. CB Channels are also indicated.

A new audio output circuit feature is the Auto-Response which auto­ matically narrows and widens the frequency range of the audio output, depending upon the gain required. This feature permits the receiver to be used as a high-fidelity receiver on stronger signals, while pro­ viding the sharp cutoff required in receiving communication b"gnals.

A second advantage of the Hammarlund Auto-Response is the rapid damping of the audio power in the speaker voice coil which greatly min­ imizes undesirable speaker "hangover." The receiver may be used with eithe r speaker or headphone s. Fast acting AVC maintains a constant audio leveL Adequate filtering practically eliminates AC power ripple.

The HQ-lOOA is equipped with a stable beatfrequency oscillator which provides the operator with a continuous range of audio tones when re­ ceiving telegraph code signals, or excellent single - side band reception.

An "S" meter is provided to obtain accurate reading on received phone signals and to assure "on-the-nose" tuning. A send-receive switch is provided to silence the receiver while transmitting.

Large, comfortable controls in logical groupings are provided for greate st operating ease. The new futuristic front panel is clearly marked to permit full attention to the operating at hand.

The HQ-lOOA was designed with you in mind. You'll have many hours of pleasure and use in operating this truly fine communications instrument.

1

2

RECEIVER figure 2. Installation of Single-wire Antenna

300 OHM TV TWIN LEAD

RECEIVER figure 3.

Installation of folded Dipole Antenna

INSTALLATION

UNPACKING

Unpack the receiver carefully. Make sure the tubes, associated tube shields and pilot lamps are in place.

SPEAKER CONNECriON

Connect a 3.2 ohm permanent magnet dynamic speaker (Hammarlund S-100 Speaker) to the two ter­ minals marked SPKR. on the rear of the chassis.

(Note Figure 4). For best performance do not place speaker on top of receiver cabinet.

POWER CONNEUIONS

Before inserting attachment plug into power outlet, make certain power source is of proper voltage and frequency. (Refer to paragraph one of INTRODUC­

TION. )

INSTALLING ANTENNA

The HQ-100A is designed to operate with a single wire or a balanced type antenna. The front panel an­ tenna trimmer control (Figure 5) permits a good match to most antennae systems of 50 to 600 ohms.

For general coverage, single wire antennae of 20 to 50 feet length will provide surprisingly good recep­ tion. A long single wire outdoor antenna, such as shown in Figure 2, will generally provide entirely satisfactory performance. This wire may be 50 to

150 feet long.

For best reception, the antenna should be isolated as much as possible from neighboring objects and at right angles to power lines or busy highways so as to minimize possible interference pickup.

Optimum performance on a particular amateur band or other narrow tuning range will be obtained by using a tuned half-wave dipole or folded dipole fed with 300 ohm transmission line or other suitable lead-in, as shown in Figure 3.

To tune the one-half wave length dipole, the follow­ ing formula for the length of the antenna may be used:

Length (feet)

=

Fre~~8(MCS)

Each half (1/4 wave length) is half the length found from the above formula.

A good ground, although not always necessary, will generally aid in reception and reduce stray line hum.

Reversal of polarity of power cord plug may possibly further reduce line hum in some locations.

CABINET CHASSIS o

3.2 OHMS

METER

ZERO

PHONES ADJUST o o

figure 4. Connection Points at Rear of Chassis

3

17

1

2

3

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4

INDEX

NO.

5

6

7

1

2

3

4

8

CONTROL

Automatic Clock-Timer Control

Function Switch

ANTENNA Trimmer

MAIN TUNING Control

SENSITIVITY Control

MAN.

-AVC

Switch

Band Selector Switch

Noise Limiter Switch

INDEX

NO.

9

10

11

12

13

14

15

16

17

CONTROL

AUDIO GAIN Control

Electrical BAND SPREAD Control

SELECTIVITY Control,

Q -

Multiplier

Frequency Control, Q Multiplier

"S" Meter

Electrical Band Spread Dial

BFO Frequency Control

Main Tuning Dial

Telechron Automatic Clock-Time.

Figure 5. location of Controls

.'

OPERATION

Basically, all that is necessary to operate a radio receiver are the tuning and volume controls. The addi­ tional controls found on the front panel of a communica­ tions receiver such as the HQ-100A, control functions which greatly improve operating performance and make possible reception of oth~rwise unintelligible signals.

NORMAL CONTROL SETTINGS

For "normal" operation such as broadcast, short wave listening, etc .• the position of the various con­ trols should be as follows:

Function Switch . .

ANTENNA Trimmer

· Receive (REC.)

· Tune for highest "S" meter reading on sig­ nal.

MAIN TUNING Control . . . Tune for highest "S" meter reading on sig­ nal.

SENSITIVITY Control

· Fully clockwise

MAN. -AVC Switch. .

· AVC

Band Selector (TUNING. · Set to desired frequen­

RANGE MCS) Switch cy range.

Noise Limiter Switch

AUDIO GAIN Control.

· OFF

· Adjust for proper lev­ el.

BAND SPREAD Control.

· Set counterclockwise to

"100" on band spread dial.

SELECTIVITY Control . . . OFF

Frequency (FREQ. ) Control . Set pointer to trian­ gular marking.

CODE SIGNAL RECEPTION

For reception of code signals, the controls should be set as follows:

Function Switch . .

ANTENNA Trimmer

MAIN TUNING Control

· BFO

· Peak for maximum out­ put on "S" meter.

· Peak for maximum out­ put on "S" ,meter.

SENSITIVITY Control

MAN. -AVC Switch .

Band Selector (TUNING

RANGE MCS) Switch

Noise Limiter Switch .

AUDIO GAIN Control .

SELECTIVITY Control

BFO FREQ Control.

Adjust for desired out­ put level.

Manual (MAN.)

Set to desired frequen­ cy range.

OFF or ON as required by local noise condi­ tions.

2/3 to

3/4 clockwise ro­ tation.

ON position

Tune signal to zerobeat with pointer on zero and then offset either left or right for des ired pitch.

FUNUION SWITCH

Three operating and an OFF position are provided.

For AM reception the REC position is used. CW or

SSB signals may be received with the FUNCTION switch on BFO.

If the receiver is used with a trans­ mitter the switch should be in the SEND position.

SINGLE SIDE BAND OPERATION

The setting of the controls for Single Side Band reception is the same as for CW reception with the

BFO being used for carrier reinsertion. The BFO fre­ quency control should be set approximately 2-1/2 divisions to the left or right of the zero indice, de­ pending upon whether the upper or lower sideband intelligence is desired. Final tuning should be accom­ plished with the BAND SPREAD control in order that proper speech registry be achieved.

BAND SPREAD OPERATION

The BAND SPREAD control may be used for fine tun­ ing by Betting it at apprOXimately gO'on the band spread

5

6 m dial and tuning in the signal with the MAIN TUNING control. Final peaking of the signal is then accom­ plished by adjustment of the BAND SPREAD control.

It should be understood that the setting of the BAND

SPREAD control will affect the Main Dial calibration in that a higher frequency setting of the main tuning dial will be required. Rotating the band spread dial from 100 toward 0 tunes the receiver to a lower frequency.

For Band Spread operation in the amateur bands, the following procedure must be followed: The main tuning dial is set to the line marking the high frequency (right­ hand end) of a given amateur band. The Band Spread tuning and calibration may then be accomplished solely with the BAND SPREAD control and dial.

20BS

SWITCH POSITION

A separate switch position is provided on the

TUNING RANGE control for spreading the 20-meter band. This switches in another band spread capacitor for optimum spreading of this band.

TElECHRON AUTOMATIC TIMER

If your receiver is equipped with the built-in 24 hour Telechron Automatic Clock-Timer, the following instructions should be noted:

Every radio-frequency device is stable only at pre­ determined operating temperatures. In order to elim­ inate waiting for receiver to warm-up to operating temperature,' the Telechron'Timer automatically turns on the receiver ahead of anticipated operating time.

This is accomplished by setting the hand of the timer

(small knob at rear of receiver) to approximately one­ half hour before operating hour. The front panel con­ trol under Timer is then set to "Auto" position. The function switch is set to REC. The receiver is then automatically turned on at the desired time.

The clock hands are set by the rear knob. Push in on the knob to set the switch timing hand and pull out on the knob to set the clock hands. The front switch is setto AUTO and the operation switch is set to REC. when it is desired to use the automatic clock switch for pre-warming the receiver before operation or for use as an alarm to turn the receiver on to a pre-tuned station. To use the operation switch normally, the clock switch should be left in the ON position.

The clock will continue to run as long as the receiver line cord is connected to the power outlet, and is ex­ tremelyusefulfor checking sign-in periods and sched­ ules.

If your receiver is not equipped with the Telechron

Automatic Clock-Timer, and you would care to have the accessory added, clock kits, with full installation instructions. may be had by writing

Harnmarlund Manufacturing Co.

73-88 Harnrnarlund Drive, Mars Hill, North Carolina or by contacting the nearest Harnrnarlund dealer.

POSSI BlE RECEIVER 01 FFI (UlTI ES

1. If, upon turning the function switch from "off" to "receive" position, the dials are not illumi­ nated and the receiver fails to operate after two minutes, this indicates that the clock timer switch just above the function switch is nat·in the proper position. This switch should always be in the ON position unless auto timer is em­ ployed. distortion is preferable to excessive pulse type noise, such as ignition interference.

3. Erratic S meter performance, lack of sufficient variation, etc., is usually due to the two 6BA6 tubes employed in the S meter circuit. These are the tw06BA6tubes, V5 and V6, in the sche­ matic diagram. Merely interchanging these tubes will sometimes provide sufficient im­ provement. Replacing one or both may be found advisable before suspecting other troubles.

2. Excessive hum or failure of the Qmultiplier to operate properly will usually be due to a de­ fective 12AX7 type tube. Such a defective tube may test good in a tube tester but be unsatis­ factory because of higher than normal heater­ to-cathode leakage. Poor noise limiter action is usually due to a poor or defective 6BV8 type tube. The use of the noise limiter will result in some distortion which must be tolerated for most efficient noise limiting. Because of this" when listening to broadcast stations or oth'er strong local signals, the noise limiter switch should be in the "off" position unless the slight

4. Excessive drift, after allowing sufficient time for warm up, may be due to a poor type 6C4 tube, V3, in the diagram or 6BE6, V2, in the schematic diagram.

Ninety-nine percent of all receiver trouble has been found to be due to one or more defective tubes. This can undoubtedly b e attributed to the rough handling equipments receive in shipment. Please, therefore, be sure to follow the above suggestions in addition to haVing all tubes tested before writing the Home Office.

CIRCUIT THEORY

The HQ-100A basically a single conversion, four­ band, superheterodyne receiver with a noise limiter.Its circuitry incorporates a Q-Multiplier for full control of selectivity and a stable, beat frequency oscillator.

PRESELEGION

The antenna input coupling and RF amplifier stage provide the necessary preselection and gain for high performance and rejection of undesired signals. The high signal level at the mixer grid,

V2,

contributes to a favorable signal-to-noise ratio.

Both grid and plate circuits of the RF stage are tuned; individual tuning coils are selected for each band.

The antenna compensating compacitor, adjustable from the front panel, permits the receiver to be resonated for optimum performance with the par­ ticular antenna in use.

CONVERTER STAGE

A high degree of oscillator stability is attained by the use of a separate mixer (6BE6) ,

V2,

and an inde­ pendent oscillator (6C4),

V3.

The output signal from RF amplifier Vl is heter­ odyned with the output of the local high frequency oscillator,

V3, and electronically combined within

the mixer tube, V2,.

On the four frequency ranges the local oscillator is 455 KCS above the signal fre­ quency.

Low-loss tube sockets, low-loss, phenolic temper­ ature compensating capacitors, and stable, coaxial trimmers all contribute to oscillator stability. Addi­ tional frequency stability is attained by applying regu­ lated voltage to the oscillator circuit and by the rugged construction of the entire HF oscillator section as­ sembly.

Q MULTIPLIER

The Q-Multiplier frequency control prOVides a means of peaking any signal within the pass band of the IF amplifier. The degree of peaking is controlled by the SELECTIVITY control. This same SELECTI­

VITY control when turned completely counter-clock­ wise disconnects the Q-Multiplier.

If interference is experienced, either between sta­ tions close to one another or from an interfering SW signal, gradually advance the Q-Multiplier selectivity control from its normally off or extreme counterclock­ wise position. This will result in increased selecti­ vity by producing a spike of narrow bandwith that is adjustable from approximately 3 KCS to 100 cycles in width. The narrowest bandwith being obtained by adjustment of the Q-Multiplier selectivity control to the point just below that which would cause the

Q-Multiplier to break into self-oscillation as evi­ denced by the receiver blocking with a resultant loss of volume.

The Q-Multiplier is generally never employed on the standard broadcast band or when short wave broadcast stations are being received. The use of the

Q-Multiplier under these circumstances will only result in limiting the frequency response of the broad­ cast band and short wave broadcast stations in view of the very narrow band width that is provided by the

Q-Multiplier. Of course, the SELECTIVITY control will make it possible to control this response charac­ teristic.

If, by chance, when receiving foreign short wave broadcast stations interference is experienced caused by two stations operating very close to one another, the Q-Multiplier maybe employed under these circumstances to minimize, if not eliminate, the inter­ ference by the improved selectiVity or decreased band width proper adjustment will provide. The proper use of the Q-Multiplier can actually enhance many times the result obtained with this receiver.

In view of this" it is suggested that a little time be spent in learning just how to properly adjust the Q-Multiplier frequency and selectivity controls under different receiving condi­ tions. As the Q-Multiplier SELECTIVITY control is advanced, a decided decrease in noise will be ap­ parent. This is due to the narrowing of the pass band.

On AM phone signals this control will usually be be­ tween the 7 and 11 o'clock positions. The FREQUEN­

CY control should then be adjusted for clarity of sig­ nal or for minimum adjacent channel interference.

The SELECTIVITY control may be advanced progres­ sively more for SSB and CW reception. The more this c·ontrol is advanced, the more critical the setting of the FREQUENCY control becomes. Advancing the

SELECTIVITY control too far will cause the Q-Multi­ plier to oscillate. This should be avoided. The Q­

Multiplier is a very handy tool in the hands of an experienced operator and, unfortunately, it is beyond the scope of this instruction manual to attempt to be more definite than we have.

IF AMPLIFIER

Seven, stable tuned circuits, in two stages of IF amplification (V5 and

V6),

contribute to sensitivity and selectivity. Iron core permeability-tuned trans­ formers improve performance and add to the ease of adjustment. The intermediate frequency is 455 KCS, the EIA standard.

Ave SYSTEM

Automatic Volume Control minimizes fading and signal strength variations by controlling the gain of the RF stage Vl and the IF stage

V5.

As a result, a comfortable and constant level of audio is maintained.

7

8

"S"

METER ICARRIER LEVEl]

The "S", or Tuning, Meter is provided to assist in tuning and to give an indication of relative signal strength. Because the meter reading are propor­ tional to AVC voltage, it is operative only in the AVC position.

The meter, which is calibrated to 40 db over S-9, is factory adjusted so that a signal input of approxi­ mately 50 microvolts gives a reading of S-9. Each

"S" unit indicates a 6 db increase, eqUivalent to doub­ ling signal strength. Should meter readjustment be necessary:

L Set function switch to REC.

2. Set front panel SENSITIVITY control to "10" and

Q-Multiplier SELECTIVITY control to OFF.

3. With receiver off, mechanically zero pointer with a fine screwdriver.

4. With AVC on and the ANT. terminals shorted, zero pointer with ZERO ADJ potentiometer

R-15.

DETECTOR AND NOISE LIMITER

One diode section of the 6BV8 tube, V7, is used for the second detector and AVC system. This system produced a minimum of distortion.

The other diode of V7 operates as a series, self­ adjusting noise limiter.

It will reduce automobile ignition and other types of impulse noise to a mll1l­ mum. Intelligibility is not affected by the noise lim­ iter, although it may be switched off if desired.

BEAT FREQUENCY OSCILLATOR IBFO]

The BFO is activated by the FUNCTION switch for reception of CW or SSB signals or as an aid in loca­ ting weak SW broadcast stations. The BFO control is used under these conditions to vary the pitch. Each calibration diVision of this control represents approx­ imately 1000 cycles. When receiving single side band transmission, the generally accepted procedure of setting the beat frequency oscillator approximately

1000 cycles above or below zero beat should be em­ ployed. In other words, if the beat frequency oscil­ lator FREQ. control is set one degree clockwise or counterclockwise from the center position, optimum single side band reception will usually be obtained.

Whether the beat frequency oscillator control will be set clockwise from zero beat will depend on whether upper or lower side band is being transmitted. If the beat frequency oscillator is on the wrong side of zero beat, it may be impossible to obtain intelligibility of the single side band signal when the band spread dial is tuned very slowly through the single Side band sig­ signal. Should such a condition arise, merely rotate the FREQ. control from the one degree counterclock­ wise to the one degree clockwise position and then very carefully adjust the BANDSPREAD for intelligi­ ble speech. The BFO frequency control may also be

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employed as a fine tuning adjustment to obtain desired speech quality. Here again experience is the best teacher. The stability of both the high frequency os­ cillator and the beat frequency oscillator employed in this receiver plus the excellent mechanical rigi­ dity will prOVide excellent single side band reception.

Refer to the paragraph on the Q-Multiplier operation for increase selectivity or narrowing of the passband usually permissable with CW and sideband reception.

It may be found desirable to place the function switch on BFa while tuning to aide in locating weak signals.

As a result of activating the BFO, each carrier tuned in will produce a beat note or whistle easily discern­ able.

If a phone signal is located in this manner, adjust the bandspread tuning control for the lower pitch tone or zero beat. This will result in centering the desired phone signal and now placing the function switch on REC will allow for normal AM operation.

AUDIO AMPI.IFIER

The first audio stage is a resistance coupled voltage amplifier employing the other section of the l2AX7

(V4B). The audio output stage is a 6AQ5 beam power amplifier (V8) prOViding an undistorted output level of at least one watt.

A feature ofthe audio system is the variable negative feedback employed (see Auto-Response Curve, Figure

6). Maximum feedback is provided at low settings of the AUDIO GAIN control for the fine quality reception of local broadcast and strong short wave stations.

As the AUDIO GAIN control is increased, the feedback decreases so that on reception of weak signals addi­ tional selectivity is prOVided by the audio section. This results in an increased signal-to-noise ratio. A further advantage is the critical damping of the speaker for elimination of speaker "hangover". This upgrades the reception of speech and music and decreases the noise output of the receiver. A further advantage is the reduction of distortion at lower settings of the

AUDIO GAIN control.

ACCESSORIES

A

Now you can get even more out of your HQ-lOOA receiver!

The XC-lOO Crystal Calibrator is available, pro­ viding checkpoints every 100 KCs within the range of the receiver.

The kit is qUickly and easily installed. It is com­ plete with eas y-to-follow instructions ,operating switch and mounting hardware.

This is not usually required by the average short wave listener, although it will prove an aid as a means of correcting for possible dial error.

The amateur operator will find this of most value since the 100 KCS checkpoints this unit provides, will make it possible to accurately set amateur band edges.

This will result in improving the accuracy of the am­ ateur band spread dial, by determining the exact set­ ting of the main tuning dial.

9

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SERVICE AND

REALIGNMENT PROCEDURE

NOTE

To service this receiver, disconnect from power source and remove all leadwires attached to terminal connections at rear of chassis apron.

Carefully turn the receiver up onto the front panel face on a smooth clean surf~ce.

Remove the two #10 hex machine screws at the extreme ends of the chassis apron at the rear of the cabinet, and the knob from the clock adjustment shaft if receiver is so equipped. Lift cabinet straight up and off of chassis. To reassemble, use reverse procedure.

ANTENNA ADJUSTME.II.IS

ADJUST SWG AT

1.2

M.C

ADJUST SLUG AT L65

Me

ADJUST SWG AT IOMC \

WITH ANT. CAPACITOR

NEAR M I N.CAPACITY

WITH ANT. CAPACITOR

NEAR

MID.

CAPACITY

WITH

ANT. CAPACITOR

NEAR MID CAPACITY

/ ADJUST SUJG AT 4MC

WITH ANT. CAPACITOR

NEAR MID. CAPACITY

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IF ADJUSTMENTS

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BOTTOM SLUG ADJUST TOP SWG ADJUST

AT 1.65 MC FOR MAX.

AT 4MC BOTTOM

AMPLITUDE

SWG ADJUST AT

10

MC

TOP SLUG ADJUST AT

.6MC BOTTOM SLUG

-J/ '\

ADJUST AT 1.65MC

R

F ADJUSTMENTS

TOP SLUG ADJUST AT

4MC BOTTOM SLUG

ADJUST AT 10 MC

H

F OSc. ADJUSTMENTS

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View

of Chassis

10

IF ALIGNMENT

NOTE

Use a non- metallic alignment tool such as Gen­ eral Cement Co. No. 5097, or equal. a. Connect the output cable of a 455 KCS unmodu­ lated. signal generator to the bus lead of the

6BE6 mixer gnd. The frequency accuracy of the generator may be checked with sufficient precision by picking up its second harmonic

(910 KCS) in any receiver whose calibration at

910 KCS has been checked as correct and then adjusting the generator frequency. b. Connect aDC vacuum tube voltmeter, set for neg­ ati ve voltage reading to pin S of the V7, 6BVS socket. c. Set the receiver controls as follows:

BAND SPREAD dial on 100

Function switch on REC.

Main tuning dial on . 54 MC

Noise limiter switch on OFF

AUDIO GAIN control at minimum

SELECTIVITY control on OFF

Band selector switch on . 54 1. 6 MC

MAN. -AVe switch on MAN.

SENSITIVITY control on 3 from maximum. d. During alignment, adjust the generator output and the SENSITIVITY control to prevent over­ loading. Final adjustment should be made with the SENSITIVITY control at approximately the third indice from its maximum (clockwise) posi­ tion. Adjust each of the three IF transformers fo,(' maximum meter reading. Topside adjust­ ments (Figure 7) are secondaries or grid cir­

figure

B.

Bottom

View

of Chassis

11

12

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cuits; bottom of chassis adjustments (Figure 8) are primaries or plate circuits. ment should be accomplished by combined or alternate adjustment of the oscillator and RF for maximum amplitude. e. Turn the Q-MULTI. ON and adjust the SELEC­

TIVITY control clockwise to a position below the oscillating point. With its panel bushing nut loosened to permit the frequency shaft to turn without hindrance by the stop, adjust the FREQ. control to obtain a maximum meter indication.

The input signal must be adjusted to a value just sufficient to obtain a good meter swing. This adjustment is the center frequency of the pass band. While the meter is at maximum, turn the stop lug to a position 180 degrees directly opposite the stop pin in the frequency shaft.

Holding it in this position, tighten the bushing in the nut making sure that the shaft or the stop lug have not turned by checking the zero setting.

NOTE

The trimmer adjustments, if required, should be the final adjustment for each band. See Fig­ ure 8 for location of trimmers.

There is no RF amplifier adjustment for the

. 54 - 1. 6 MC band. f. Note that the oscillator frequency in the HQ-100 is always on the high side of the signal frequency by 455 MCS. Therefore, it is necessary to make sure that the oscillator frequency is not adjusted below the signal frequency which would be an image response of the signal. f. Turn FUNCTION switch to BFO. With the BFO frequency control on ZERO adjust the slug in

L7 for ZERO beat with the AVC-MAN switch on MAN position and the SENSITIVITY control adjusted at a position below overload. g. It will be necessary to repeat low and high end alignment adjustments of each band since the adjustments are interdependent. The process should be repeated until maximum amplitude is obtained at both alignment frequencies of each band. g. With the MAN. -AVCswitchon AVC, the SENSI­

TIVITY control at maximum, with grid pin 1 of the V5 amplifier tube grounded, and with no signal input, adjust the METER ZERO ADJUST. pot at the rear of the chassis (Figure 4) for a reading of zero on the "8" meter.

RF ALIGNMENT

NOTE

Use a non-metallic alignment tool such as Gen­ eral Cement Co. No. 8282, or equal. a. The slugs and trimmers, having been factory adjusted, should require a minimum amount of adjustment for any realignment. b. All R F and oscillator slug adjustments are made from the top of the shield cans. See Figure 7. c. Connect the unmodulated, signal generator out­ put cable to the antenna and ground terminals of the receiver, with the A terminal adjacent to the G terminal jumped together. See Figure 4. d. Set the controls the same as for IF alignment above. Adjust the SENSITIVITY control as re­ quired to obtain a sufficient voltmeter read­ ing and to prevent overloading. e. The oscillator adjustment is made first. The

RF is adjusted next to obtain maximum ampli­ tude. The antenna slugs are adjusted last. A certain amount of interaction will occur between the oscillator and RF adjustments, partiCUlarly on the higher frequency bands. Final adjust­

NOTE

The receiver should be warmed up at least one-half hour before final oscillator frequency adjustments are made for the dial calibration check.

DIAL CAI.IBRATION

a. Use a crystal calibrator haVing 100 KCS and

1000 KCS output. Set the arbitrary band spread dial scale to 100. Set the function switch to

BFO. Set the BFO FREQ. control to zero. Set the SELECTIVITY control toOFF. Set the MAN.

-AVC switch to

MAN. b. Check to see that the frequencies at or near the alignment frequencies are "on the line." If not, make minor adjustments of the slugs and trim­ mers (Figures 7 and 8) to make them correct.

CAUTION

Weaker signals will be observed at dial settings apprOXimately 10 KC8 above each calibration dial marking. These are image signals from

1 MC above the desired signal and may be re­ cognized by their somewhat weaker strength and may be further reduced by proper adjust­ ment of the gain controls. They will, of course, be more noticeable on the higher bands. Keeping the antenna tuned will help.

--.

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Figure 9. Se'ectivity Curves

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TABLE 1. TUBE SOCKET VOLTAGES

MEASURED FROM TUBE SOCKET PINS TO CHASSIS WITH VTVM AUDIO GAIN MINIMUM. BAND SWITCH ON 10 TO 30 Me.

LIMITER OFF. AVC-MAN SWITCH ON MAN. SENSITIVITY MAX. OPERATION SWITCH ON REC. Q-MULTIPLIER OFF.

LINE VOLTAGE 117. NO SIGNAL INPUT.

TUBE

SOCKET NO. 1

2

SOCKET PIN NUMBERS

3 4

5

6

7 8 9

V1RF

6BZ6

V2 MIXER

6BE6

V3 HFO

6C4

V4 12AX7

Q MULT. 1st A-F

V5 1st IF

6BA6

V6

2nd

IF

6BA6

V7 6BV8 DET

LIM AVC BFO

VB 6AQ5

AUDIO OUTPUT

V9 OA2 V-R

-6

90

90

105

1.8

1.3

-8 BFO ON

13

6.3 AC

6.3 AC

6.3 AC

1.5

6.3 AC

6.3 AC

110 BFO ON

6.3 AC

6.3 AC

210

205

90

200

200 95

1.2 AC

-.2

-9 BFO ON

210

105

105

70

-3 TO -9

60

100

205

.....

CJ1

TABLE 2. TUBE SOCKET RESISTANCES

BAND SWITCH ON 10-30 MC. MEASURED FROM TUBE SOCKET PINS TO CHASSIS. AUDIO GAIN MAXIMUM.

OPERATIONS SWITCH ON REC. BFO OFF. LIMITER ON. SENSITIVITY MAXIMUM. AVC-MAN ON MAN.

TUBE

SOCKET NO.

-

VI RF

6BZ6

V2 MIXER

6BE6

V3 HFO

6C4

V412AX7

Q MULT. 1st AF

V5 1st IF

6BA6

V6 2nd IF

6BA6

V7 6BV8 DET

LIM AVC BFO

V86AQ5

AUDIO OUTPUT

V9 OA2 V-R

1

10K

2.4M ON AVC

22K

2

180

180

SOCKET PIN NUMBERS

3 4

5

0

0

.5 MEG INF

0

6800

.5 MEG

2.2 MEG

16KSEL OFF

0

2.4M ON AVC

0 0

470K

0

0 lOOK

.5 MEG

.5 MEG

430

0

0

.5 MEG

BFa ON

0

INF

0

0

0

0

0

0

0

0

0

.5 MEG

.5 MEG

.5 MEG

.5 MEG

.5 MEG

47K

0

.5 MEG

.5 MEG

.5 MEG

.5 MEG

.5 MEG

1 MEG 2200

180

10K MIN

SENS -

200

10K MIN

SENS -

3.3

6

120 K

.5 MEG

.5 MEG

.5 MEG

INF

7

0

0

0

8 9

0

0

.5 MEG

0

2.2 MEG 190 K lOOK LIM OFF

16

Ll

L2

L3

L4

L5

L6

L7 m

Sche=atic

Designation

PARTS LIST

Description

Hammarlund

Part No.

CAPACITORS

Variable, Main tuning . . • • • . . . . . • . . . . . . • . . • . • . . . . . • . • . . . . . • . . • . . . . • . . . 9441-60-40003

Variable, Bandspread . . . . . . . . . . • . . . . • . . . . . . . . . . . . . . • . . . . . . . . . . . . . • • . • 9441-60-40004

Variable, Antenna Co=pensator . . . • . . • . • . . . . • . . . . . . . • . . . . . . . . . . . . . . . . . 9434-45-40038

Fixed, Ceramic disc. 01 mf 1000V . 1509-01-01001

C53

C54

C55

C56

C58

C59

C60

C1, A thru C

C2, A thru F

C3

C4, 5, 6, 7,8,9,10,

15,19,30,31,32,

34,35,36,41,48

Cll, 12, 13

C16, 17, 18

C20,21,22,23

C24

C25

C26,57

C27

C28

C29

C33, 45, 46

C38

C38A

C38B

C38C

C42

C43,44

C47

C49,50

C51

C52

Rl,32

R2

R3

R4, 10

R5

R6,33

R8

R9,34

Trimmer 1-8 mmf 500V . . . . . . . . . . • . • • . . . . . • . • . . . . . . . • . . " . . . . . . • . . • . .

Fixed, silver mica, 100 mmf 500V . . . • . . . . . • . • • . . . . . . • . . . . • . . • . . . . • . • .

Variable 1-8 mmf 500V. . . • . . . • • . . . • . . . • • . . . . • • • . • . • . . . • . . .' . • • . . . . . . • .

Fixed, silver mica 430 mmf 300V . . . • • . . . . . . • . . . . . • . . . . . . • . • • . • . • • • . . .

Fixed, silver mica, 1300 mmf 500V . . . . . • . . . . . . . . . . . . . . . • . . . . . . • . . . . . .

Fixed, silver mica, 3000 mrnf 500V . . . . . • . . . • • • . . . . . . • . . . . . . . • • . . . • . . .

Fixed, silver mica, 1100 mrnf 500V . . • . . . . • . • . . . . . . . . . . . • . . • • • . . . • • • . .

Fixed, silver mica, 3300 =mf 500V . . • . . . . • • . . . . . • • . . . . . . • • • . . . . . . . . • .

Fixed, silver =ica, 510 =mf 500V . . • . . . . . . . . . . . . . . . . . . • • . . . . . . • • • . . .

Fixed, Ceramic disc, .04 mf 600V . • . . . • • • . . • . . . . • . . . . • . . . . . . . • • . . . . •

Fixed, Three-section electrolytic . . . . • • . • • • • • . • . . . . . • . . . . . . . • . . . • • • • . .

60 rnf 450V (Part of 1517-01-00001)

40 rnf 450V (Part of 1517-01-00001)

25 mf 50 V (Part of 1517-01-00001)

Fixed, Ceramic disc, .005 mf 1000V. . . . • . . . . . . • . . . . . . • . . • . . . . . • . • . . • . .

Fixed, Ceramic disc, . 01 rnf 1400 V . . . . . . . . . • • • . . . . . . • . . . . . • . • . . • . • . . .

Fixed, Discap, temperature compensating, 6.8 mmf . . . . . . . . . . . . • • . . • . . . .

Fixed, Discap, temperature compensating, 2.7 =mf . . . . . . . • . . . . . • . . . . • •

Fixed, Discap, te=perature compensating, 6.8 mmf . . • . . . . . . . . . . . . . . • . •

Fixed, Ceramic, temperature compensating ..••. '" ... '" . . . . • . • . • • • . . . non-insulated,

1,

5 mmf

Fixed, Silver mica 5 mmf 10% 500V . . . . • . . . . . • . . . . . . • . . . . . . . . . . . . . • . . .

Fixed, Ceramic disc, 4.7 mmf 5% N220 . . • . . . . ,. . • . . . . • . . . . . . . . . . . . . • . . .

Fixed, Ceramic disc, .02 MFD 500V . . • . • . . . . . . • . . . . . . . . . . . . . . . . • • . • • .

Fixed, Silver mica 350 mmf, 20% 100V. . . . • . . . • • . . . . . . . . . . • . . . . . . . . . . . .

Fixed, Silver mica 220 mmf 5% 500V. . . . • . . . . • • . . . . . . . . . . . . . . . . . . . . . . . •

Variable . . . . • . . . . . . '" . • • . . . . . . . . . . . . • . . . . • . . . . . . . . . . . " • . . . . . • . . . . .

Fixed, Silver mica 2mrnf ±. 5 mmf, 500V . . . . . . • . . • . . . • • . . • • . . • . • • . • . . .

1527-01-00001

1519-01-00001

1527-01-00002

1519-02-03010

1519-02-03011

1519-02-03009

1519-01-03001

1519-02-05001

1519-01-03002

1509-01-01005

1517-01-00001

1509-01-01003

1509-01-01015

1509-01-00022

1509-01-00001

1509-02-00003

1509-01-02002

1519-01-00003

1509-02-00024

1509-01-01016

1519-02-00053

1519-01-00007

9434-45-40038

1519-01-00024

COILS

R. F. Coil Assembly (Bands 1 and 2) . . . . . . . . • . . • . • . . . . . . , . . . • • . . . . . . • • . 1809-01-00005

R. F. Coil Assembly (Bands 3 and 4) . . . . . • . . . . . • • . . . ., . • . • . . . . . . . . • • . . . . 1811-01-00011

H. F Osc. Coil Assembly (Bands 1 and 2) . . . • • • • . . . . . . . • . . . . • • . • . . . . • . • •

1809-01-00006

H. F. Osc. Coil Assembly (Bands 3 and 4) . . • . • . • • . . . . • • . . . . • . • . • . • • . . . .

Coil and Ferrule Assembly . . • . . . . . . • • . . . • • . . . . . • . . . . . . . . . . . . . • . • . • • • .

Choke, Filter, 13 Henries at 65 ma D. C . . . . . . • • . • . • . . . • . . . • . . . . • • • . . . .

BFO Coil . • . . . • • . • . • . . . . . . • . . . • • . • . • . . • . . • . • . • . . • • . . . . . . . . • • • . • • • • • •

1811-01-00012

9001-03-00118

5626-02-00001

1804-02-00055

RESISTORS

22 Ohms, 1 /2W . . . . . • . • . . . . . . . . . . . • • . • . • • . . • . . . . . . • . • . . . . . . • . • . . . . . . . 4703-01-00312

Potentiometer, 10,000 Ohms . . . . . . . • . . . . . . . . . • • . • . . • . . . . • . . • • . . . • . . . . . 4735-02-00001

10,000 Ohms, 1/2W . . . • . . . • . . . . • . • . . . • . • . . • • . . . • . • • . . . . . . . . . • . . . . • . . •

4703-01-00344

1,000 Ohms, 1/2W . • • . . . . . . . . . • . . . . . • • . . • • . . . . • • . • . . . • . . . . . • . . . • . . . . .

4703-01-00332

22,000 Ohms, 1/2W . • . . . . • . . . . . . . . . . • . . . . . • . . . . . . . . . . . • . . . . . . . . . • . . • •

4703-01-00348

180 Ohms, 1/2W . • . . . . . . . . . . . . . . . • . . . . . . • . . . • . . . . . . . . . • . . . . . • . . . . . • . .

4703-01-00323

6,200 Ohms, 1 /2W . • . . • . • . . . . . . . . . • . . . . • . . • . • . . • . . • . . . . • . . . • . • . . • . . . .

4703-02-00466

47,000 Ohms, 1/2W . . . . . . . . . . . . . . . . . • . . • • • . . . . • . . . . . . . . . • . • • • • • . . • . • .

4703-01-00352

------------------@

PARTS LIST

Schematic

Designation

R11

R12

R13

R14, 16, 21, 29, 35

R15

R17

R19

R20

R27

R28

R30

R31

R36

R37

R38

R39

R40

SlA, SIB

SIC

S2

S3

S4

S5

Tl

T2

T3

T4

T5,

6, 7

T8

T9

CRl,2

Fl

Fl

II,2

Jl

Ml

P2

P2

Description

Hammarlund

Part No.

RESISTORS (continued)

2.2 Megohms, 1/2W .

6,8000hms,l/2W . . . . . • . . . . . . . . . . . . . . . . • . . . . . . . . . . . . . . . . . . . . . . . . . .

4703-01-00372

4703-01-00342

Potentiometer, 10,000 Ohms . . . . . . . . . . . . . . . . . • . . . . . . . . . . . . . . . . . . . . . . . 4735-01-08002

2,200 Ohms, 1 /2W" " .

Potentiometer, 200 Ohms . . . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . . . . . . . . . . . .

4703-01-00336

4735-01-00200

1,600 Ohms, 1/2W 5% . • • . . . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . . . . . . . . . . . . .

180 Ohms, 1/2W 5% . • . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . . . . . . . . • . . . . . . . . .

4,000 Ohms, lOW .

4703-02-00452

4703-02-00429

4714-01-01002

Potentiometer, 1 Meg • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4735-01-00002

47 Ohms, 1/2W . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . . . . . . . . . . . . . . . . '. 4703-01-00316

100 Ohms, 1/2W. . . . . . . . . . . . • . . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4703-01-00320

430 Ohms, 1W . . . . . . . . . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4704-02-00738

10 Ohms, 1/2W. . . . . • • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . .

470K Ohms 1/2W . . . • . . . . . . . . . . . . . . . • • . • • . • . . . . • . . . . . . . • . . . . • . . . . . . . .

4703-01-00308

4703-01-00364 lOOK Ohms, 1/2W . . . . . . . . . . • • . • • • • • . . . . . . . . . . • . . . . . . . . . . . . . . . . . • . . . •

4703-01-00356

3.3 Ohms, 5W. . . . . . . . • • . . . . • . • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4713-01-00001

22 Ohms, 1W. . . . . • . • • . • . • • . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . . . • . . . . . . . .

4704-01-00612

SWITCHES

Switch Wafer RF . . . . . . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • . • . • • • . . . 5105-01-00007

Switch Wafer HF Osc . . . . . . . . . . . . . • . . • • • . . . . • • . • • . . . . . . • . • . . . . . . . . . . .

Power-On-Off, SPST (Part of R13)

5106-02-00005

OFF-REC BFO, Single Section, four position . . . • . • . . . . . • • • . • . • • . . . . • . . . 5106-02-00007

MAN. -AVC, SPST...••••.••••..•......••.•..••••..•.•••••••••••.•....

5101-01-00001

LIMITER, SPST . . . . . . . . • . • . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • • . • . . . . . .

5101-01-00001

TRANSFORMERS AND COIL ASSEMBLIES

Antenna Transformer Assembly (Band 1) . • . . • • • • • • . . • . • • . . . . . . . • . • . . . . .

Antenna Transformer Assembly (Band 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . •

Antenna Transformer Assembly (Band 3) . . . . . . • . . . . . . . . . . . . . . . . . . . . . . . .

Antenna Coil Assembly (Band 4) . . • • • . . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Transformer, 1st, 2nd, and 3rd 1. F. .. .

Transformer, Output, Max power 5W, impedance match; 10,000 Ohms plate to 4 Ohms voice coil.

.

Transformer, Power, Primary 115V /230V . . . . . . . . . . . . . . . . . . . . • . • . • • . • .

50-60 cps.

1809-01-00004

1810-01-00010

1811-01-00010

1812-01-00012

1811-01-00018

5618-01-00002

5603-01-00011

MISCELLANEOUS

Diode, Silicon CER72C . • . . . . . . . . • • • . . . . . . . . . . • . . . . . . . . . . • . . . . . . . . . . . . 4807-01-00001

Fuse, 1 amp (115V Operation) . . . . . . • • . . . . . . . . . . . . . . . . • • • . • . • . . . . . . . . . .

5134-01-00201

Fuse, 1/2 amp (230V operation) . . • • • • • . • • . . . . . . . . . • . . • . . • • • . • • • . • . . . . . 5134-01-00213

Lamp, pilot #47, 6.3V, . 15A . • . . . . . . • • . • • . . . . . . • . . . . . . . . . . • • • • • • . . . . .

3901-01-00001

Phone Jack . . . . . . . . . . . . . . • . • . . . . . . . . • . • . . . . . . . . . . . . . . . . . . . . • . . • • . • . .

2109-01-00001

Meter

"s"

(Carrier Level) . . . • . . • • • . . • • . . . . . . • • . • • • . . . . . . . . . . . • . . • . • • •

2902-01-00003

Adapter (115V) . • . . . . • . • • • • • . . . . • . . . • • • • . . . . . . • . . . . . • . . • . . • • • • . . . . . . • 9001-03-00028

Adapter (230V) . . . . . . . • • • • • • . . • . . • • • • . • . . . . • . . • . • . . . . . • • • • . . . . . . . . . • •

9001-03-00029

Telechron Clock Assembly (115V/60 cps) . • • . • • • . . • . . . . . . . . . . • . • • • • • . . . •

9207-01-00001

Telechron Clock Assembly (230V /60 cps) . • . . . . . . . . . . . . . . . . . • • . • • • • • . • . .

9207-01-00002

Telechron Clock Assembly (230V /50 cps) " . • . • . . . . . . . . . . . . . . . •

9207-01-00003

Crystal Calibrator XC-I00. . . • • • • • . . . . . . • . • • • • . • . • . . . . . . . . . . . • • . • • . • . .

9205 -00-000 11

17

18 m

ADDITIONAL HINTS FOR THE NOVICE AND SHORT WAVE I.ISTENER

A voltage reading of 45 - 50 volts may be obtained between the chassis and a ground as the result of the two power line by-pass condensers that are connected across the power line with the center tap grounded.

Since we are dealing with AC, these capacitors will look like resistors to a volt meter. This will also produce a slight shock if the chassis is not grounded, and one happens to contact a grounded object, and the chassis or any exposed part of the receiver. This al­ so will account for a slight spark, if the receiver is connected to the power line and the ground connection is made. For protection a good ground should always be employed.

In using the receiver for CW, or with the BFO, it is absolutely necessary to take the receiver out of the AVC position and put it into the Manual position.

Failure to do this will result in the receiver blocking and erratic action of the S meter. The S meter is only usable in the AVe position. When using BFO, the audio control should be used at 2/3 to 3/4 rotation clockwise position and the RFsensitivity control em­ ployed as a means of adjusting volume.

When employing the

Q multiplier for phone use the function switch will, of course, be in the REC posi­ tion and it is advisable to start with the Q mUltiplier selectivity control in the 10 to 12

0' clock position.

If this control is advanced past approximately the 2 o'clock position, the

Q multiplier may go into oscil­ lation resulting in the blocking of the receiver. For use on phone the

Q multiplier selectivity control, will also usually be employed between maximum counter clock wise position and approximately straight up.

Beyond this point or even at approximately the straight up position the receiver is usually so selective that it is capable of wiping the modulation off the carrier by actually rejecting the side bands. For normal phone use or broadcast reception the selectivity control should always be employed in the OFF counter clock wise position, since this results in the operation of a switch which disconnects the

Q multiplier from the

IF system.

If it is desirable to use the BFO to locate a station when tuning for weak signals, after the carrier is tuned in, merely rotate the function switch from the

BFO position to the Receiver position which will re­ sult in turning off the BFO for phone reception. If interference is experienced either between stations close to one another, or an interfering CW signal, turn the

Q multiplier selectivity control. Gradually advance the

Q multiplier selectiVity control which will result in increasing the selectivity by producing a spike of narrow band width that is adjustable from apprOXimately 3 kc to 100 cycles in width. This spike can be moved around within the IF pass band that is nominally apprOXimately 6 kc wige. The frequency control is the means for varying the position of this spike. Assuming that the selectivity control is ad­ jus ted to produce a spike 1 kc wide and also ass uming that the band width of the IF system is 6 kc wide, it can be appreciated that the shape of the IF system response curve can be varied by moving the 1 kc band width anywhere within the 6 kc band width. This will produce a valley on either side of the spike or peak.

By proper tuning, therefore, of the band spread dial and the frequency control of the Q multiplier, it should be apparent that an interfering signal may be placed in a valley and the desired signal on the peak, with the net result of decreasing the strength or elim­ inating the signal that is in the valley, without seri­ ously affecting the deSired signal intelligibility.

Since the use of the

Q multiplier naturally means narrower band Width, it should only be employed when interference is present. Never use the

Q multiplier on the broadcast band unless you are hunting weak DX signals and are therefore not after maximum fidelity response. The same, more or less, applies to short wave broadcast listening. Here the use of the

Q mul­ tiplier in addition to functioning as previously de­ scribed may also prove advantageous from a noise reduction standpoint as a direct result of the de­ creased band width.

------------@

MEMORANDA

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MARS HILL. N.C

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THE HAMMARLUND MANUFACTURING COMPANY

Standard Warranty

The Hammarlund Manufacturing Company, warrants this equipment to be free from defects in workmanship and materials under normal and proper use and service for the uses and purposes for which it is designed, and agrees to repair or replace, without charge, all parts thereof showing such defects which are returned for Inspection to the Company's factory, transportation prepaid, within a period of 90 days from date of delivery, provided such Inspec­ tion discloses to the satisfaction of the Company that the defects are as claimed, and provided also, that the equipment has not been altered, repaired, subjected to misuse, negligence or accident, or damaged by lightning, excessive current or otherwise, or had its serial number or any part thereof altered, defaced, or removed. Tubes shall be deemed to be covered by the manufacturer's standard warranty applicable thereto, and such Items shall be and are hereby excluded from the provisions of this warranty. Pilot lamps and fuses are not guaranteed for length of service.

Except as herein specifically provided, no warranty, express or implied, other than that of title, shall apply to any equipment sold hereunder. In no event shall the Company be liable for damages by reason of the failure of the equipment to function properly or for any consequential damages.

This Warranty Is valid for the original owner of the equipment, and Is contingent upon receipt of the Warranty Registration Card by the Company. No equipment shall be returned to the factory for repairs under warranty unless wri"en authorization is obtained by the Company, and the equipment is shipped prepaid by the owner. The Company maintains Authorized

Service Stations, names and locations of which will be sent upon request of the owner.

The Hammarlund Manufacturing Company

A

Giannini Sci.ntific Co.

73·88 Hammarlund Drive, Mars Hill, N.

C.

Expo" Departmant: 13 East 40th St,eet, New Yo,k 16, N. Y.

Th. policy of tha Hammarlu.... Manufacturing Campony, is ona of continuad improvemant in dooign and manufacture wharever and whanaver possibla, to provida tha higha.t attainobla quality a .... porformanca. Hanca, .pacifica­ tion., finishOl, ate. are subject to maltJa without notice a .... without a.sump­ tion by Hammarlund of any obligatIon or responsibility to provide sum features

CIS may ... manged, odded or dropped from previous production runo of thi. aqulpment.

Hammarlund Manufacturing Company

A Giannini

Scientific

Co.

73-88 Hammarlund Drive. Mars Hill. N.

C.

Export Department: 13 East 40th Str.et, New York 16, N. Y.

DO NOT

MAKE ANY RETURNS WITHOUT AUTHORIZATION FROM THE

FACTORY. ALL AUTHORIZED RETURNS SHOULD BE SHIPPED TO HAMMAR­

LUND MANUFACTURING CO., ATTN. CUSTOMER SERVICE, MARS HILL, NORTH

CAROLINA.

- - -

-----~-----.-..~~~~----~~------~----

ESTABLISHED r9ro