Eico HF-60 User manual

HIGH FIDELITY 60 WATT AMPLIFIER
HF-6D
ELECTRONIC INSTRUMENT CO. INC.
3300 NORTHERN BLV0..L. I. CITY 1. N. Y.

MODEL HF50 &HF60 ADDENDA (Book'jj™^)
Page 6indicates that the HF50 and HF60 can operate safely with line voltages up to 124 volts
and recommends the use of avoltage adjusting device when line voltages exceed this value
(paragraph *3). The power transformer now provided permits the use of this instrument on line
voltages up to 132 volts without component failure being likely. IF your line voltage is 121 volts
or less, connect th>e black-red lead to the fuseholder. Tape up the exposed end of the loose
black-green lead and tape this lead with friction tape to the black-red lead so that it does not
hang loose In th$ chassis.
If your line voltage is between 121 volts and 132 volts, connect the black-green lead to the
fuseholder. Tape up the exposed end of the loose black-red lead and tape this lead with
friction tape to the black-green lead so that it does not hang loose in the chassis. If you are
j~ certain as to your line voltage, or think that it may be high, connect the black-green lead
to the fuseholder and tape up the black-red lead as above. For voltages exceeding 132 volts
avoltage regulator or adjusting device must be used. However, line voltages exceeding
132 volts Is unlikely.
When adjpsting the bias and balance controls, adjust the line voltage to 112 volts if the black-
red lead Is connected to the fuseholder, and 125 volts if the black-green lead is connected to the
fuseholder (page 5).
Please made the following changes In the construction book if you are building this unit from
akit:
(A) If your line voltage is leu than 121 volts, step 7on page 7C should read:
7. ()Fig. 3. Cut the black lead from hole "Y" to 3" and connect to J5“1 (C).
Cut the black-red lead to 51/2" and connect to XF1~1 (S). Tape the exposed
end of the black-green lead to insulate this wire and tape the lead to the black-
red wire so that it does not hang loose.
(B) If your line voltage is greater than 121 volts, step 7on page 7C should read:
7. ()Fig. 3. Cut the black lead from hole "Y" to 3" and connect to J5~l (C).
Cut the black-green lead to 51/2" and connect to XVI “1 (S). Tape the exposed
end of the black-red lead to insulate this wire, and tape the lead to the black-
green wire so that It does not hang loose.
l.E. 1089 Electronic Instrument Co. ,Inc., 33“00 Northern Blvd. ,L.I.C. 1, New York

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MODEL HF 60 HIGH FIDELITY 60 WATT AMPLIFIER
general description
GENERAL
The EICO HF-60 is abasic power amplifier designed for
flawless reproduction of the entire dynamic and frequency
range achieved In present-day microgrove and tape re-
cordings. Enormous undistorted reserve power, excellent
transient response, and exceptional stability result in ef-
fortless response to peak power demands, well-defined
bass, clean treble, and an overall crystal clarity of the
reproduced sound without false emphasis anywhere In the
audio spectrum.
The circuit employed Is avariant of the British Mullard
type including agenuine Ultra-Linear output stage, a
combination now recognized as one of the very best pos-
sible amplifier designs. Aplus factor In the EICO HF~60
is the use of the ACRO TO-330 output transformer, the
very finest in its power class. Other factors worth con-
sidering in the choice ofan amplifier are detailed in the
list of features below.
The HF”60 has been designed to maintain its excellent
characteristics under speakerload as wellas theresistive
load normally used fortesting. Phase corrections have
been provided ot both extremes of the audio spectrum to
Insure stability under all conceivable conditions and to
insure that variations in components and construction will
not affect the performance. Overload characteristics
are excellent and the HF“60 will not exhibit bounce or
flutter under pulsed conditions.
The Model HF~60 can be operated from any source cap-
able of delivering a1/2 volt Input signal. The source
maybe onypreamplifler-contro! unit or acombined tun-
er-preamplifier-control unit. An excel lent preamplifier-
control unit, designed to take its operating power from
the HF”60, is the EICO Model HF"61A High Fidelity
Master Control. The Model HF“61 is identical to the
HF-61A except that it contains its own power supply.

FEATURES
l1
.
EF86 phenomenally low -noise, high gain, voltage
preamplifier,
2. Direct coupling between voltage preamplifier and phose
inverter to eliminate otime constant.
3. 6SN7 GTB cathode-coupled ("long-tailed") phase in-
verter for forced balance over the entire frequency and
dynamic range. Provides drive for the output stage from
equal and comparatively low impedances.
4. EL34/6CA7output pentodes in apush-pull Ultra-Un-
ear output stage operating with fixed bias.
5. Fully potted ACRO TO“330 Output Transformer_the
"heart" of the amplif?er_provides alevel of performance
previously thought unattainable at acompetitive price.
It is manufactured from the finest and costliest materials
on special winding equipment, using unique, patented
design methods. Each transformer is extensively tested
and a-c balance Is guaranteed to 1%.
6. Heavy duty power transformer with reserve capacity
SPECIFICATIONS
for powering any preamplifier.
7.
Extra-rugged GZ34 rectifier tube with Indirectly heat-
ed cathode to eliminate high storting voltage on the e-
leetrolytlc filter capacitors and to delay the application
of the full B+ voltage to the amplifier tubes until they
have wormed up.
B. Input level control.
9. Fuse and panel mount fuse holder.
10. Control of bias voltage for output tubes.
11.DC Balance adjustment of output tubes; convenient
metering terminals provided.
12. Standard octal socket provided for preamplifier power
take-off and remote on-off switching.
13. Switched and unswltched AC convenience outlets.
14. Heavy gauge steel chassis.
Rated Output Power:60 watts continuous; 130 watts peak.
IM Distortion (60 &6000 cps at 4;1):Below 1% at 60 watts; below 0.5% at 50 watts.
Total Harmonic Distortion:Below 0.5% at any frequency from 20 cps to 20 kc within 1db of 60 watts.
Undistorted Sinusoidal Frequency Response ;±0.5db 5cps to lOOkc at Iwatt level; ±0. 1db 15cps to 35kc at any level
from 1milliwatt to 60 wotts; no peaking or raggednes* outside audio range.
Square Wove Response :20cps to 25kc essentially undistorted; 3micro-seconds rise time; no overshoot at any frequency or
power level nor visible rounding below 15kc,
Inverse Feedback: 21 db
Stability Morain:16db
Damping Factor:Above 12, 20 cps to 20 kc; 17 at lkc
.
Sensitivity; 0.52 volt for 60 watts out.
Hum; 90 db below rated output
Speaker Connections: 4, 8, ond 16 ohms
lubes; 2“ EL34/6CA7, I- EF86/Z729, 1- 6SN7GTB, 1- GZ34
Power Source: 1 T
0
—120 volts, 60 cycles; 150va at no signal, 200va at signal developing rated power, 250 va at signal
developing peak power (overload); 3amp fuse.
Size: HWD -7" X14" X8"
Weight; 30 lbs.
2

Bweclsanical Installation
GENERAL
a) HEAT DISSIPATION (VENTILATION): In common with
other electronic equipment, the Model HF“60 produces a
great deal of heat in normal operation. Unless contin-
uous and adequate air flow Is obtained around the heat
producing elements, these elements will overheat and their
useful lifewill be greatly curtailed. Adequate ventilation
will be provided If the amplifier is installed in an open-
back console provided that the top of the amplifier is spaced
at least two inches below an/ shelf mounted above it.
If the cabinet Is enclosed at the rear, provide several large
hole* or slots as low down and as high up in the cabinet
back as possible. As an alternate, holes may be provided
in the sides, bottom, or top of the cabinet. The Impor-
tant thing to remember is that effective venti lotion re-
requires provision for cool air to enter at the bottom and
to leave at the top.
If the amplifier is not installed in aconsole. It should be
situated preferably on an open surface. An attractively
finished matching cover for the Model HF"60 Is available
which will provide a"finished" appearance as well os
protection when the amplifier is not Installed in aconsole.
Four rubber feet are also provided so that the amplifier
will not mar the surface of furniture onwhich it isplaced.
b) ACCESSIBILITY TO PARTS: Tubes ore the most fre-
quently replaced items In electronic equipment, if the
amplifier is placed in aconsole, sufficient space should
be allotted to reach and remove any tube in the ampli-
fier. Furthermore, Input and output terminals of the am-
plifier should be accessible to permit easy interchanging
of system components for comparison. If antennas are
strung around the back of the console In which the ampli-
fier is Installed, arrange them so they will not Interfere.
c) ELECTRICAL ISOLATION: To realize the full benefit
of having apower amplifier physically separate from the
preamplifier-control unit and/or tuner, the power ampli-
fier should beplaced at least one foot awoy (more if pos-
sible) from either or both of these units.
d) ACOUSTICAL ISOLATION: If amplifier and speaker
are installed in the same cobinet, provide sufficient sep-
aration to minimize mechanical speaker vibration reaching
the amplifier. The minimum separation is about one foot.
CONSOLE MOUNTING
Having determined aproper location for the amplifier in
the particular console, the correct procedure for mounting
the amplifier chassis is as follows: a) If the rubber feet
have been inserted in the bottom plate, remove them (pry
out with athin screwdriver), b) Remove the 10 screws
which fasten the bottom plate to the chassis, c) Place the
bottom plate (bumps facing up) at the location on the she If
or other mounting surfoce in which it is desired to mount
the amplifier. With asharp pencil, placed with its point
directly against the edge of the lower surface of the bottom
plate, draw the outline of the bottom plate on the shelf
and also mark the positions of the two extreme holes on
both the long sides (front 8. rear), d) Remove the bottom
plate and drill each of the marked holes on the shelf to a
diameter of 1/4" .e) Refasten the bottom plate to the
chassis, with the 6*8 X3/8 screws previously removed,
using the center holes on each of the long sides and the
two holes on each of the short sides, f) Roplac.o the
chassis on the shelf, positioning it exactly In the outline
previously drawn, g) From the bottom side of the shelf,
insert a*8 X1" screw with a1/2" flat washer against the
head through eachof the fourfront and rear holes. These
screws engage the stamped nut over each hole on the
chassis flange and when tightened secure the chassis to
the shelf.
eleefr&cal installation
POWER
o) POWER REQUIREMENTS: The EICO Model HF-60 re-
quires 200 watts at 110 to 120 volts, 60 cycles AC.
b) REMOTE SWITCHING: The EICO Model HF"60, al-
though not provided with its ownON-OFF power switch,
has provision for remote switching, through an octal socket
mounted on the chassis. Pins 6and 7of the octal socket
are Infernaiiy connected to the ends of abreak in one
power transformer primary lead and are externally con-
nected together by a jumper in amole octal plug inserted
in the octal socket. When this male plug is removed, pins
6and 7may be brought out to an external AC switch,
usually in apreamplifier unit. This is one of the connect-
ion functions accomplished with the octal plug-and-cable
attached to the EICO HF-61A preamplifier-control unit,
if the MF“60 power amplifier is being used with aself-
powered preamplifier, such as the EICO HF~61 ,or aself-
powered tuner-preamplifier, the octa! plug furnished with
the HF”6Q remains inserted in the octal socket (to connect
the primary of the power transformer to the AC line ond to
ground oneside of thefllament windingjand the line cord
of the HF“60 Is inserted in aswitched 117VAC conven-
3

ience outlet in the control unit. Note: When using a
self-powered preamplifi er-controi unit, touch one end of a
wire to the preamplifier chassis and the other end to the
power amplifier chassis. If aspark occurs, pull out the
HF-60 line cord plug ond re-inserf it with the prongs re-
versed .
c) POWERING AUXILIARY PREAMPLIFIER: The some
octal socket provides all necessary filament and B+ voltages
foroperating an auxiliary preamplifier-control unit. 6.3
volts AC filament voltage, at 1ampere, may be obtained
from pins 1and 2; pin number 4on the socket supplies
350 volts DC, at amaximum current of 10 milliamperes;
and pin 3Is connected to ground. As stated above, con-
trol of 117 volt AC line power to the power amplifier,
and, indirectly, power for the preamplifier-control unit
itself, is made available through the connections to pins
6and 7. This arrangement Is exactly suitable for power-
ing the EICO HF-61A preamplifier-control unit; all that
need be done is to remove the octal plug provided with
the HF"60 from the octal socket and insert the octal pi ug-
and-cable of the HF-61A in its stead. Note thot aJumper
between pins 2and 3of the octal plug furnished with the
HF"60 effectively grounds one side of the filament wind-
ing; removal of the octal plug leaves the filament wind-
ing floating. This arrangement is used because abum bal-
ance control Is connected across the filament leads In the
EICO HF-61A preamplifier and the arm of this control is
returned to atop In the B+ supply to provide asuperim-
posed DC potential on the filament supply for purpose of
minimizing hum due to cathode-heater leakage in the
preamplifier tubes.
d) CONVENIENCE OUTLETS: When the HF-60 Is used
with apreamplifier thot takes power from it, such as the
EICO HF61A, the convenience outlets of the HF-60 will
be found useful .Theoutlet marked" 117 VAC SW. N("SW.”
is an abbreviation for "SWITCHED") Is "live" or "dead"
depending on whether the preamplifier powerswitch turned
to ON or OFF; plug tuners into this outlet. The outlet
marked "117 VAC" is not switched and Is "live" whenever
the HF-60 line cord plug Is inserted in awall outlet; plug
arecord changer Into this outlet In order to protect the
mechanism. When the HF-60 Is used with aself-powered
preamplifier, such os the EICO HF~61 A, normally the con-
venience outlets on the preamplifier will be used. How-
ever, the HF“60 outlets may be used also, If desired. In
which cose both of them will be "switched"
.
INTERCONNECTION OF COMPONENTS
SIGNAL
a) PREAMPLIFIER -CONTROL TO POWER AMPLIFIER:
Single conductor, shielded cable must be used to inter-
connect the preamplifier-control unitor tuner-preampli-
fier-control unit and the power amplifier. Unless the
source has alow Impedance output, such as acathode fol-
lower (with which up to 50ft. of coble can be used), use
the shortest possible connection; in ony case, use a low
capacity type of shielded cable (as low as 25mmf capacity
per foot Is available). Both ends of the coble must be
fitted with RCA type phono plug connectors.
b) SPEAKER CONNECTIONS: To connect your speaker
to the amplifier properly, you must know Its rated Imped-
ance, which is usually marked on the speaker or specified
In the manufacturer's literature. Connect one speaker
lead to the terminal on the rear apron marked "G" and
the other speaker lead to the nearby terminal designated
by the rated speaker impedance (4,8, or 16 ohms). Plastic-
covered lamp cord may be used for distances up to 50 ft.
with little power loss. For shorter distances, tv antenna
lead can be used, particularly if It Is desired to run the
speaker lead under arug.
If It is desired to use two similar or identical full-range
speakers of the same rated impedance (either 8or 16 ohms
only) for better sound distribution, connect one speaker
lead of each pair to "G" and the two remaining leads to
the terminal with anumber equal to half of one of the
speaker's rated impedance. (It may be necessary to "phase"
the two speakers by reversing both of the leads from one
of the speakers.) This may not be done if each of the
speakers is designed for reproduction of adifferent part
of the audio spectum (woofer-tweeter combinations), In
which case across-over network is required which connects
to the amplifier with only one pair of leads.
INTERCONNECTION PROCEDURE
a) Make all system interconnections before applying AC
power. Making or breaking Interconnections while AC
power is applied will result in amomentary overload of
both the power amplifier and speaker system with possible
damage to either or both.
b) If the EICO HF”61 Apreamplifier control unit (notself-
powered) has been obtained in kit form, remove all the
jumper connections in the octal plug supplied with the
HF-60 and wire the preamplifier power take-off leads to
this plug as follows:
Color of Preomp. Lead Pin of Octal Plug Connected to
grey 6
grey 7
brown 1
brown 2
red 4
black 3
Wired HF-61A preamplifiers will have the preamplifier
leads connected to the octal plug as in the table above.
c) If it is desired to use apreamplifier without apower
supply other than the HF“61A, the power take-off leads
of the preamplifiershould beconnected to theHF”60octal
plug (after removing the Jumpers) as follows:
Preamp. Power Leod Pin of Octal Plug Connected to
AC ON-OFF 6
AC ON-OFF 7
filament (6.3 VAC) 1
filament (6. 3VAC) 2
B+ 4or 5*
ground 3
*Ifthe preamplifier requires 350VDC, use pin 4; If the
preamplifier requires less than 350VDC, use pin 5and

connect adropping resistor of appropriate value and vol-
tage rating from pin 4to pin 5of the octal socket on the
HF"60 chassis. For example, if the preamplifier in quest-
ion requires3Q0VDC 0+ voltage at lOma drain, the drop-
ping resistor will be required to drop the voltage by 50
volts (350-300 =50}ct acurrentof lOma. By Ohm’s Law,
the required resistance in ohms is the voltage drop In volts
divided by the current in amperes or 50 volts/. 01 amp. =
5000 ohms. The power dissipated in the resistor in watts
is equal to fhevoltage drop in voltsmultiplied by the cur-
rent In amperes or 50 volts X.01 amp =0.5 watts. For
safety aresistor of double the wattage rating should be
used. Therefore, a5000 ohm 1watt resistor is required.
maintenance
CONTROL ADJUSTMENTS
There are three controls in the HF“60 amplifier. Two of
these controls, the BIAS ADJ. and the BALANCE ADJ.
,
must be adjusted by kit builders before initial use of the
amplifiers—factory wired units will have had these ad-
justments made. The BALANCE ADJ. will have to be re-
adjusted by all users whenever one or both of the EL34
output tubes Is replaced or if it Is suspected that adc im-
balance in the output tubes has occured In the course of
use. The third control is the INPUT LEVEL ADJ. which
Is set after all the systems components are interconnected
and are actually operating. If the INPUT LEVEL ADJ.
willnot be accessible after mechanical Installation, then
the systems components should be Interconnected and turn-
ed on before mechanical Installation to permit the proper
setting of this control.
a) PRELIMINARY BIAS &BALANCE ADJUSTMENTS: Be-
fore applying power, set both the BIAS ADJ. control and
the BALANCE ADJ. control at the approximate center of
their ranges of rotation. Then connect to AC power, turn
the amplifier on, and allow about one minute for warm-up.
If the plates of the EL34 output tubes turn cherry-red dur-
ing warm-up, turn the BIAS ADJ. control counter-clock-
wise until redness is just barely visible (normal condition).
If the redness does not disappear even at full counter-
clockwise rotation, which Indicates an abnormal condition,
him off the power and recheck the amplifier wiring and
components.
}) SETTING BIAS ADJ. CONTROL (BIAS VOLTAGE AD-
JUSTMENT): Use either aVOMof at least 20,000 Qper
/oltsensitivityand ±3%accuracy on dc voltage measure-
ment or aVTVM. Set the instrumentat the minus or neg-
ative DC volts functions and arange of not less than 50
/oltsormore than 150 volts (the closer the po inton
rhescale at which the reading is made is to full scale, the
nore accurate it is). Rest the amplifier on the short side
>n which is located the input jack and remove the bottom
Mate. Locate the arm (center contact lug) of the BIAS
kDJ. control and connect the "hot" meter lead to it.
touch the common or ground meter lead to any unpainted
Joint on the chassis (ground) and read the negative dc
voltage on the meter. Adjust the BIAS ADJ. control for
areading of -47 dc volts (negative). Disconnect the
meter leads when this is completed.
c) SETTING BALANCE ADJ. CONTROL: Set the VOM
or VTVM at either the plus ar minus DC voltage function
and select the lowest DC voltage range. Connect the
meterleads to the twoMETER pins jacks on the rear chassis
apron. If the meter pointer deflects to the left of zero,
reverse the leads. Adjust the BALANCE ADJ. control for
azero or minimum reading. This completes the balance
adjustment, whereupon the meter leads can be removed
from the METER pin jacks.
d) Set the VOM or VTVM at the plus DC voltage function
ond select the lowest DC voltage range (not higher than
3volt* full scale). Insert the "hot" meter lead into either
one of the METER pin Jacks and touch the common or ground
meter lead to any unpainted point on the chassis (ground).
Readjust the BIAS ADJ. control for ameter reading of
0. 65 volt.
e) Repeat step c
f) Repeat step d
g) SETTING INPUT LEVEL ADJ. CONTROL: The IN-
PUT LEVEL ADJ .control is intended to protect the speaker
system from "blasting" should someone turn the pream-
plifier-control unit level controls to full, by permitting
you to attenuate the preamplifier output signal by any de-
sired amount at the input to the power amplifier where it
can not be "fiddled" with. Start by setting the INPUT
LEVEL maximum counter-clockwise (maximum attenua-
tion), using qscrewdriver. Set the LOUDNESS control
on your preamplifier to the maximum clockwise position
and the LEVEL control at the midpoint of its range of ro-
tation. Turn your phonograph on and play on average
orchestral record. Then slowly rotate the INPUT LEVEL
ADJ. control clockwise until the music is at normal (or
concert) listening level. This completes the adjustment,
which need not be repeated.
5

TROUBLE SHOOTING and OPERATING NOTES
Your amplifier should require little service except for nor-
mal tube replacement. We recommend no substitutions
for the tube types used in this amplifier. The EF86, EL34,
and GZ34 types are distributed national ly by the Amperex
Electronic Corporation (230 Duffy Ave. ,Hlcksvilie, L. I.
,
N.Y.) and Mullard Ltd. (international Electronics Corp.
,
81 Spring St., N.Y. 12, N.Y.) If necessary, replace-
ments can be obtained directly from EICO.
itshould be noted that slight red coloring of the EL34 out-
put tube plates in operation is not abnormal and does not
indicate that the amplifier is operating improperly.
The HF"dO is intended for operation at aline voltage of
117 volt AC. Component failure Is likely at a line vol-
tage above 124 volts AC. if the line voltage at your lo-
cation Is higher than 124 volts, use avoltage adjusting
device or voltage regulator of adequote volt-ampere ca-
pacity (minimum 250VA),
To facilitate servicing, remedial and trouble-shooting pro-
cedures havebeen provided in the TROUBLE SHOOTING
CHART that follows. AVOLTAGE AND RESISTANCE
CHART is also provided as an aid in locating defective
components and to permit acareful, stage-by-stage check
of the amplifier. DC operating voltages are given both
at no signal and at asignal developing 50 watts output as
well os the corresponding 1kc signal voltages.
To Isolate the source of unusual hum or noise in your
system, first turn off the AC power and then unplug the
audio cable connecting to the amplifier input. Then turn
the AC power on again and note whether hum or noise has
decreased, tf It has, the fault Is In the preamplifier or
associated equipment and measures should be taken to cor-
rect it as described in the service notes for these urtlts.
If it is desired to provide agood building ground for your
entire system, run olead from under speaker connection
terminal "G" to acold water pipe. Da not connect such
aground wire to other components in the system.
If the trouble is no output or low output and the amplifier
Is suspected, check AC signal voltages storting at the In-
put and working step-by-step toward the output, using a
sine-wave audio signal generator and aVTVM. Turn the
INPUT LEVELADJ. control maximum clockwise (no atten-
uation) and set the input signal to 0.4 volt. The corre-
sponding grid and plate signal voltages for this input are
Indicated on the schematic diagram .This procedure should
suffice to localize the defective stage.
If the trouble is an excessively distorted output, try tube
replacement, signal tracing or procede directly to voltage
and resistance measurements.
When the defective stage is localized, procede to are-
sistance and voltage check of the stage, using the data in
the Resistance and Voltage chart. Disconnect the ampli-
fier from the power line and discharge capacitors prior to
making any resistance check and prior to removing either
both of the EL34 output tubes or disabling the bias supply.
Do not turn the amplifier on with either oftheoutput tubes
removed or with the bios supply disabled .
CHECKING ATYPICAL TUBE STAGE
1. Check tube.
2. Check plate and cathode resistors.
3. Check coupling capacitors for leakage or short.
4. For output Stage, check dc resistance of transformer
windings.
5. Check grid leak resistor for open.
6. Check cathode by-pass capacitors for short.
7. If no or low B+ voltage on tube, check decoupling
path for open or defective R9, and filter copocitorCH
and Cl 1for short.
8. if wiring and circuit components including the tube
check O.K. and B+ voltage Is excessive, check the de-
coupling path for short or defective R9.
SERVICE
If trouble developesln your instrumentwhich you con not
remedy yourself, write to our service department listing
all possible indications that might be helpful .Ifdesired,
you may return the instrument to our factory where it will
be placed in operating condition for $5.00 plus the cost
of parts replaced due to theft being damaged in the course
of construction. NOTE: Before returning this unit, be
sure all parts are securely mounted. Attach atag to the
instrument, giving your home address and the trouble with
the unit. Pack very carefully in arugged container, us-
ing sufficient packing material (cotton, shredded news-
paper, or excelsior), to make the unit completely immov-
able within the container. The original shipping carton
is satisfactory, providing the original Inserts are used or
sufficient packing material is inserted to keep the instru-
ment immovable. Ship by prepaid Railway Express, If
possible, to Electronic InstrumentCo. ,Inc, ,33”00 North-
ern Blvd., Long IslandCityl, N.Y. Return shipment will
be made by express collect. Note that acarrier cannot be
held liable for damages In transit if packing IN HIS OPIN”
JON, is insufficient.
6

CHASSIS
MOUNTING
serted
from
the
inside
of
the
chassis
apron.
Use
two
each
of
the
following:
3C

4C

Likewise,
mount
the
two
post
left,
I
post

J2
R20
IOC
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