Dumont 180, 183, 182, 181 User Manual

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DU MONT TYPE 180

Twenty-two Tube, AC, Superheterodyne, Television Receiver

GENERAL FEATURES

No expense has been spared in the production of these
receivers and every up-to-date television and radio
development has been incorporated. These receivers are
classed as "Electrostatic and Direct Vision." Electro-static
indicates that the entire deflection system is electrostatic
and since the picture is viewed direct, without the use of a
mirror, lens or other device, it is referred to as Direct
Vision. The latter ensures clarity, brilliance and the widest
angle of vision. Steady, clear cut, black and white pictures
that are large enough for all the family to enjoy at one
time are secured by the use of a fourteen inch cathode-ray

A separate high fidelity section brings superb
reproduction of the sound channel which is associated
with the picture. A single control tunes both the sight and
the sound channels so the receiver is no more difficult to
operate than an ordinary broadcast receiver, To the above
features add its compact size, minimum number of
controls and simple straight forward layout and you will
have an idea of the first commercial television receiver
which we believe you will find easy to install and service
in spite of the apparent complexity of the subject
Television.

tube which furnishes a picture eight by ten inches

TECHNICAL INFORMATION

Frequency Ranges – Four Television Channels provided, present alignment as follows:

AUDIO VIDEO
STEP STATION SIDEBAND CARRIER CARRIER
A NBC Single 49.75 45.25
B CBS Single 55.75 51.25
C …… …… …… ……
D NBC Double 49.75 46.5

Power Ratings

Power supply 110 to 120 volts, 50 to 60 cycles, 250 watts.

Audio output, maximum 4.25 watts.

MECHANICAL SPECIFICATIONS

Cabinet Dimensions

Height …………………………………… 24 inches
Width ……………………………………. 15 ¾ inches
Depth ……………………………………. 25 inches

Chassis Dimensions

Height …………………………………… 20 ¾ inches
Width …...………………………………. 13 ¼ inches
Depth ……………………………………. 24 ¼ inches

CONTROLS

Operating Controls…………………………6
Adjustment Controls……………………….7

Types 181, 182, 183

These receivers have the same operating controls as the
type 180 and therefore will not be covered separately

Type Purpose

1853 …………… R.F. Amplifier

6J5M ....….…….. R.F. Oscillator

1852 …………… 1
1853 …………… 1st Video I.F Amplifier
1852 …………… 2nd Video I.F. Amplifier
6H6M ………….. 2
1851 …………… 1st Video Amplifier
6V6G ………….. Video Power Amplifier
6J7G …………… 1
6J7G …………… 2
6Q7G ………….. 2
6V6G ………….. Sound Power Amplifier
6J7G ………….… Horizontal Synch Separator
6AD5G …………. Horizontal Sweep Oscillator
6R6G ...……….… Horizontal Sweep Amplifier
6J7G ………….… Vertical Synch Separator
6AD5G …………. Vertical Sweep Oscillator

6R6G ....………… Vertical Sweep Amplifier

2Y2 ..........…….... 4100 Volt Rectifier

5X3 …………….. 1600 Volt Rectifier

5Z3 .....………….. 350 Volt Rectifier

114-9-T .....……... Cathode-ray Tube (14")

TUBE COMPLEMENT

st

Detector

nd

Video Detector

st

Sound I.F. Amplifier

nd

Sound I.F. Amplifier

nd

Sound Detector and Amplifier

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CIRCUIT ARRANGEMENT

A simple straight line layout is used in these
receivers that should prove extremely helpful to the
serviceman. Viewed from the front, the video receiver is
on the left side of the chassis and the sound receiver is on
the right. Fig. No. 1 shows the front controls and the
sound receiver while Fig. No. 2 shows the rear
adjustments and the video receiver. The top portion of the
chassis contains both sweep circuits along with the
modulating circuit of the cathode-ray tube. To prevent
confusion each side is considered separately, half
appearing in Fig. No. 1 and the remainder in Fig. No. 2.
The seven auxiliary controls shown in Fig. No. 2 are
provided for the use of the installer and serviceman.
These controls are necessary to make the final alignment
of picture size and positioning when

the receiver is installed under the operating conditions
imposed by the .earth’s magnetic field. and the power
supply line voltages. Once properly set these controls do
not need adjustment and since they. were not provided for
the owner’s use we suggest that the dealer or serviceman
seal the back of the cabinet as it is not possible to tamper
with the controls when the back is in place. The use of the
parts and tubes shown in Fig. No, 1 and Fig. No. 2 can be
checked by comparing the "V” numbers, etc., with the
schematic drawings which are furnished in the back of
this manual. Four separate schematic drawings have been
provided which, due to their size, will be found more
readable than a single drawing.

CAUTION AND WARNING

The set is equipped with a safety switch which
automatically opens upon the removal of the back of
the cabinet. This protects the operator from dangerous
high voltages which would otherwise be exposed.

The serviceman that is engaged installing or
servicing television receivers is urged to take all
precautions and run no unnecessary risks. The high
voltages that are necessary with this type of equipment
are very dangerous and should not be approached in a
careless manner.

It is better to shut the set completely off between
adjustments than to suffer a painful or even a
dangerous burn.

Large cathode-ray tubes operate at high-voltages and
hence are evacuated to a very high degree of vacuum.
Therefore the atmospheric pressure on the glass can run
into tons depending on the size of the tube. A collapse
therefore is as bad as an explosion and all cathode-ray
tubes should be handled with care. The Du Mont
Laboratories have gone to great expense to provide a
cathode-ray tube that is safe for the home and the
structural design results in its ability to stand tests nearly
twice as severe as usually employed. The serviceman,
however, should observe the following rules as he will
probably be the only one to handle the average tube.

1. Be careful in handling the tube.

2. Watch the use of tools near the tube.

3. Don't scratch the surface of the glass.

4. Don’t stand the tube on a metal surface or in any
other way cause certain parts to be quickly
heated or cooled.

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INSTALLATION OF RECEIVER

Antenna Installation

In the installation of television receivers the proper
antenna is a necessity. Successful installations will result
from attention to details, while slipshod and careless work
will bring only poor customer satisfaction and repeat
calls. There is nothing difficult about the installation of
television aerials, a little patience and experience is all
that is required. Regular broadcast aerials in the majority
of cases will be found useless. Impress this upon the
owner and make a satisfactory installation regardless of
what other equipment he already has. Satisfactory picture
reception is what both of you require for the completion
of the installation.

The Dipole Antenna

The Dipole form of aerial is generally satisfactory; it
consists of two metal rods, each approximately five feet
long and placed on a line with each other. Extreme
accuracy in the length of these rods is usually not
necessary and if the receiver is located very close to the
transmitting station it may be found advisable to cut down
the length of each rod. The simple dipole aerial is shown
in Fig. No, 3.

The Lead-In

The most popular lead-in from the dipole to the
Television receiver will be a twisted pair as it is
inexpensive and generally satisfactory in locations where
the. signal is strong. The length of this lead is usually not
of extreme importance, It is best to get the Dipole located
in the clear and as. far from electrical interference as
possible than to limit its location by using a theoretical
exact length feeder, The twisted pair should be soldered to
the lugs on the Dipole as a good connection is essential
and necessary since several changes in the position of the
antenna may be required for best results. The other form
of lead-in is the coaxial line such as the Amphenol No.

72. This form of feeder should be used in installations
where the length of the lead-in is too long for satisfactory
work with the twisted pair and again where the
installation is at an extreme distance and every bit of
energy picked up must be delivered to the receiver.

Polarization

If the dipole is mounted horizontally it is said to be
horizontally polarized, and if vertical it is vertically
polarized. Since the physical location materially effects
the aerial no specific form can he advised and we can
merely suggest that you start by using horizontal
polarization and change if necessary to produce the best
results.

Location of the Antenna

Whenever possible the Dipole should be erected so
that it is in line of sight with the transmitter. This do es no t
mean that no signals can be secured where a direct view
of the transmitter cannot be obtained. Surprising results
are often secured on these high frequencies and no
concise rules can be assigned to this work. If the location
is on a street, having heavy traffic there may be
considerable noise level due to automobile ignition
systems. In this case, locate the Dipole to the rear of the
building and away from the source of the noise as far as
possible. In the case of' electrical machinery over which
you have no control, the same method can be employed
along with the utilization of the directional effects of the
aerial which will be covered later.

Room Illumination

Whenever possible the receiver should be so placed
in the home that a direct glare from either natural or
artificial light does not fall upon the face of the cathode­ray tube. The received picture may be viewed under a
variety of conditions where it is not always convenient to
darken the room completely. Adjustments made to meet
these conditions will not cause damage to the receiver.
Viewing the pictures in as dark a room as possible is
always at an advantage as it permits the setting of the
Intensity and Contrast controls in a manner that will give
picture tone values more correctly relating to those
actually used in the studio from which the picture is
transmitted.

Installation Process.

It is a good plan to proceed as follows with the
installation,
l. Erect the Dipole antenna in the clear. Start by using
horizontal polarization (mount the rods horizontal) and
turn them until their plane is at right angles with the
location of the transmitter

2. Adjust the receiver to produce a picture.

3. Return to the antenna and make final adjustments for
best signal strength and removal of ghosts, etc.

Ghost Effects

Where the picture appears to be duplicated and
slightly displaced, the additional picture is referred to as
a ghost. This effect is usually due to the refection of the
signals and can be cured by the slanting or rotating of the
Dipole or the use of a reflector or reflectors. If after all
possible positions have been tried, the ghost still exists it
will be necessary to change the location of the antenna
and try again.

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Directional Effects

In the simple Dipole, directional effects are not very
pronounced, but it does have a rather sharp no-signal
radius and it is possible in some instances to materially
reduce interference by placing the offending source in this
area. If the installation of the receiver is being made at
quite a distance from the transmitter or if the signal level
is very low due to local conditions it is well to con sider
the use of a reflector. This is done by placing a rod, about
ten feet long, parallel with the Dipole and about 5 feet in
back of it. The directional effect of the Dipole remains the
same, namely at right angles to the plane. Signals coming
from the front will be greatly increased. In using
reflectors it is well to bear in mind, however, that any
signal approaching from the rear (where the reflector is
located) will be greatly attenuated. Fig. No. 4 shows
reflector added to the simple Dipole.

Operating Controls of the Receiver (Front)

First, become familiar with the controls on the front of the
receiver. Since the receiver has been tested before
shipment, probably only a few minor adjustments will be
necessary. Therefore before touching the adjustments in
the rear attempt to operate the set according to the
instruction sheet supplied the purchaser and make only
the adjustments required. These instructions are repeated
here to cover the possible lose of the sheet. Figure No.1
shows the front of the receiver with the controls
numbered and the use and the purpose of these controls is
as follows.

1. Marked CONTRAST, ON and OFF

This is a power switch for starting and stopping a set. It
also is the volume control of the picture signal. It should
be adjusted in conjunctio n with the intensity control (No.

4) to produce a picture of pleasing contrast to the user. If
the location is such that the signal received is very small it
may be necessary to use the full gain of the control, while
in a good location it may, have to be retarded
considerably. If the picture is not satisfactory the rear
controls must be adjusted as covered in a following
section.

2. Marked SELECTOR

This control is a four position switch provided for
covering four television channels. The present alignment
was given previously under the technical information
section.

3. Marked TUNING

Only one control is necessary to properly tune both the
sight and sound channels. Simply adjust this control until
the best reception of the sound is secured and at this point

4. Marked INTENSITY

The intensity or brightness of the picture is controlled by
this knob. It should be adjusted in conjunction with
Control No. 1 to get the best picture. Note: it is a good
plan to retard (turn to the left) this control when starting
the set. If about 15 seconds is allowed to elapse before
advancing this control it will prevent a small brigh t spot
from appearing on the screen which might eventually
darken the screen.

5. Marked FOCUS

This control is used to sharpen the individual lines of the
pattern and once set seldom requires further adjustment.

6. Marked VOLUME

This volume control adjust the audio volume and has no
effect whatever upon the picture

Rear Controls of the Receiver

As previously stated the adjustment of these controls is
necessary for the final alignment of picture size and
positioning, as the earth's magnetic field and power
supply line voltages vary with locations. The location of
these controls is shown in Figure No. 2 and th eir use will
be covered in numerical order. Proceed as follows:
remove the wood screws holding in the back of the
cabinet and pull out the back. The safety switch will open
turning the set off and since it is necessary to have the set
in operation while making these adjustments the switch
can be made temporarily inoperative. (A large battery clip
is convenient for this purpose.) Do not reach into the set
with the voltages on. (See Cautions and Warning.) There
is one adjustment that cannot be made by these controls,
that of rotating the Cathode-ray tube to cause the picture
to properly line up with the viewing opening. To remedy
this, turn the set off, remove the elastic band that grips th e
rear support and rotate the tube by hand in the correct
direction.
The function of the seven rear controls are as follows

1. Vertical Frequency Control

This controls the frequency of the vertical sweep. If the
picture is not steady and slips past at intervals, vertically,
this control should be adjusted until a steady picture is
secured.

2. Vertical Size Control

If the picture is too narrow and out of proportion
vertically this control will remedy the trouble.

3. Vertical Positioning Control

As its name indicates, this Control will move the pattern
vertically, allowing the picture to be placed directly in the
center of the opening.

the picture signal will be correctly tuned.