Eckstein Radio and Television Co. 80-A Schematic

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Product Information:
Model:80-A
Manufacturer:Eckstein Radio and Television Co. (Ecko, Karadio)
Description:the Amateur

Schematics Content:

Please note: this content is a computer-generated interpretation of the above schematic and is provided only to help assist you in locating this schematic. For the actual text, please consult the schematic above. Thank you.

Page 1:

(C)John F. Rider

Page 2:

BAND _ SWITCH SHOWN

BAND 1

AT 2" POSITION
, BAND z

AT 3" POSITION
BAND 3

(C)John F. Rider

Page 3:

E KSTE N PAGE 17-5
MODELS SO-A,80~B,80-C

E RAD 0

Qw Am wwowwuo kmazuwm w>c>> :sm PUBS

Q QE cow 5me #5.5260

(C)J'ohn F. Rider

Page 4:

ECKS EIN RADIO AND TELEV. CO.

GENERAL DCRIPTION

KARADIO model BU is a 3-Band mobile communications radio receiver
lor installation in cars, trucks, buses and other vehicles lor reception
OI radio telephone signals.

BAND 1 54071650 i<.c,
KARADIO MODEL atiia (THE AiiiPoR'l'i
KARADio MODEL snrc tri-1E iii'i'i-:RNA'rloNALi
BAND l 54041650 Kc.

KARADio MODEL an is a superlieterodyne receiver designed to oper-
ate from the B-volt battery supply ol any vehicle. The circuit employ-
ed in ALL ranges consists oi One stage ol tuned RF. mixer and HF.
oscillator, one stage ol LF., second detector, one stage aI resistance
coupled Af, and Beam Power output. Automatic volume control is
also provided on all ranges. The 6" permanent magnet dynamic
speaker is specially designed for communications use and is equipped
with a transformer to correctly load the beam power output stage at

Sensitt ity is such that 5 microvolts or less input signal at antenna plug
will produce .5 watt audio output with a signal to noise ratio OI 4:1

POWER OUTPUT:
At least Z watts ot audio power is available with IUYr or less distortion.

FREQUENCY RESPONSE:

While the KARADIO MODEL 8U is designed to emphasize the voice Ire-
auencies tor communications work it is also pleasing to the ear on

TUBE REQUIREMENTS:

KARADIO MODEL 80 is supplied complete with set of matched tubes
which are tested in the receiver at the time ol alignment. The tubes

RF. PRESELECTOR - SEAS
OSCILLATOR - MIXER >> GBES
IF. AMPLIFIER - BBAS
DEMODULATOR - lst AUDIO - SATS
POWER AMPLIFIER - SAOS
RECTIFIER - SXSGT

KARADIO MODEL so is designed to operate on a DC voltage source

ol 5 to 7.3 voltsv lt is standard practice ol most car manutocturers

to set tire voltage control ol cars and trucks at about 72 volts All

operating data on KARADiOs are talten witir a source voltage ot 7

at which voltage me current is e amperesv By tire use ol a non-syn-

chronous vibrator and GXSGT rectilier tube. no polarity consideration

need be given in tire installation ot your KARADIO
INSTALLATION INSTRUCTIONS

'l'iie radio unit may be mounted to ond directly below tiieinsrrument

panel at any convenient locationv 'l'wo holes must be drilled in tire

stiitening lip ot tire instrument panel about 1/," back trom the iront ot

the instrument panel. These holes must be large enough to pass the-

two Na B mounting screws protruding tram the tcp oi the radio unit,
AIter the holes are drilled, insert mounting screws ol radio in holes,
place lock Washers and nuts On screws. These nuts must be Iastened
real tightv h is also very important that the paint he removed lroin in-
strument panel lip directly under nuts so that a good ground conriccw
tion is made

Drill a hole to pass a No. lU machine screw in the iire wall or other con-
venient place and bolt strap with series oi holes to this support and
Iasten Other end to protruding machine screw on back oi radio. This
is the back support lOr radio unit and good ground connections must
also be considered in this assembly.

The speaker power supply unit is mounted at any convenient location
on the fire wall. This is accomplished by drilling a 5/ 15-inch hole at
desired location in Eire wall and mounted with threaded stud nua and
washers provided. Care is to be taken that this mounting bolt also
IOrms a perfect ground. This cart be assured by scraping the paint
iron-i the spot under the mounting nut and washer on the reverse side
OI the bulk head.

Insert the tour-prong plug in lead Irom speaker into the socket On back
side oi radio. Connect Iused power lead from radio tO the ammeter
or circuit breaker Of the vehicle. A lD-ampere FUSE is provided in this
calole. Never replace this Iuse with one of any other size.

The antenna of the cowl type is recommended and should he 96 to 108
inches maximum length. The model 80 KARADIO is designed lor an
antenna ol this length and a low capacity shielded lead-in of 30 inches.
IT IS IMPORTANT THAT THE ANTENNA LEAD NOT BE CHANGED
LENGTH IS CORRECT TO MATCH THE ANTENNA INPUT

INSTRUCTIONS FOB mATING MOTOR
IGNITION INTERFERENCE:

Cut the high tension lead that runs from the center terminal ot the
distributor to the coil, as close as possible to the distributor end. Screw
the distributor suppressor into the lead and reconnect to the distributor,
Mount tlie generator condenser on tire generator trome under tlie
ground lead screw. connect tire spade tip on the oonderiser wire under
the battery terminal Ol the generator. Do not Connect it to the lield
terminal ol generator.

When checking the car lor motor interierence, clamp the hood down
tight with the hood clamps.

ln some installations it may he necessary ta bond the inuliler or the
transmission housing to the Irame of the car. If necessary, bond the
motor block securely to the front and rear supports. For bonding,
use Vz-inch Copper braid. Further interlerence may be eliminated by
bonding all metal control cables or pipes feeding from the motor side
ol the firewall into the car. These bonds should be made Irom the
pipes or control cables and soldered to the firewall immediater ad-
jacent to the motor side

In case ol tire static. collector springs should be inserted under the
hub caps ot the front wheelsv In some cases it may be necessary to
install such collectors in the rear wheels as well.

Interference Irorn electric gas gauges may be cured by inserting a
"dime light filter" in series with the lead near as possible to the gas

In some instances it is beneficial to attach a by-pass condenser lrorn
one side of the ammeter to the grounded part ol the instrument panel,
II the dome light is feeding interference to the antenna, the lead should
be cut where it comes lrorn the post under the dash and a switch be
inserted in the instrument panel to tum the dome light oil ond on, A
by-pass condenser connected to tire dome light lead and grounded at
tire post would serve in lieu of a switch.

The LF. Irequency is 470 I( C , alignment Ol each band should be made

First, oscillator trimmers should be adjusted tor correct dial calibration
at the high frequency end oi each band. Then, oscillator padder con-
densers should be aligned near the low frequency end ol each band
alter adjustment Oi the oscillator trimmers. Next, antenna and RF
trimmers oi all bands should be aligned near the high frequency end
of each band. This alignment should be made at a point approximate-
ly 15?/s or 1/2 tum oi the knob down from the high frequency end of
each band.

ln aligning o receiver, especially tlie antenna trimmers, it is extremely
importath that the correct ioad, which is equal to the antenna, be used.
Shielded leads iron-i signal generators or oscillators have a definite
capacity and should be considered When testing or aligning is dai-ie.

it is preferable to use an indirect connection or a condenser ot approri,
mately lou MMF in series with tire sional generator lead and tire anten.
na lead, The reason that this procedure is important is that an all
tirree bands, tire primaries ot me antenna coils are ot iiigii impedance
and are designed tor tire best impedance rnatcli at tire low trequency
end ol eacii bond. Byvusirio o greater capacity, a loss in accuracy
would result, `

Individual tubes ol the some type will vary slightly in their character4
istics and it is well to remember this lact when replacements become
necessary. Even though the circuit is designed so as to reduce the
efiect Oi such variations to a minimum. The high Irequency oscillator-
lirst detector tubes should be selected with some care. The tolerance
of the inter-electrode Capacities is enough in Ce oi some tubes tO
slightly alter the tuning. This change would be, however, most notice-
able at the high frequency end oi each band.

(C)John F. Rider

Page 5:

ECKSTEIN PAGE 17-7

PARTS LIST
L for
MODEL 80 KARADIO

_ 3 Gong 'lining cop.
Nov 14 cl-lOKE
POWER TRANSFORMER
OUTPUT TRANSFORMER
l. r. TRANSFORMER (los)
l. r TRANSFORMER (ltls)
ANTENNAE coll. RAND l
ANTENNAE coll. BAND 2
ANTENNAE coli BAND a
. R r. coll. RAND l
. R, F. COIL BAND 2
R. r. coll. RAND a
.. OsciLLATOR coli RAND l
... OsclLLArOR cOll. BAND 2
AOscll_l.ATOR coll. RAND a
..3 POS. 3 SEC o clR. SwlrcH
NON SYN. leRArOR
s" PM SPEAKER

Number Delcl'imicn
C .05 mid 200 Vv
C . .05 mid 400 V
C 100 mmid, Mica
250 mmtd, Mica
_ 250 mmid. Mica
v006 mid 600 V.
. ,015 mid 600 V.
., ., lU mid. 25 V. Electrolytic
. 006 mid 1500 VV (Oil)
. 30 mid 350 V. Electrolytic
30 mid. 350 V Electrolytic
500 mmidV Mica
.01 mid 600 V.
i 1 Megohni 1/2 Watt
. lsil Ohrn 1/2 watt
. l Megohrn l/i watt
. 25 i( Ohm l/z Watt
. 15 K Ohm l Watt
. 150 Ohiri _ 1/2 Wall
. l Megohrn 1/2 Watt
. l2 K Ohm l/z Watt
. 15 K Ohm l Watt
.. 50 K Ohm l/z Watt
. 10 Megohm 1/2 Watt
. 470 K Ohm l/z Watt
.. 470 l< Ohiri l/Z Watt
. 450 Ohm 2 Watt
. 150 Ohrn 1/2 Watt
..150 Ohm l/y Watt
. 500 K Ohm

TABULATION OF PROBABLE THOUBLES, CAUSES.
AND CORRECTIVE MEASURE:

Even though all component parts at the receiver have on ample iactor
oi saiety| ioilure may occul- in certain individual cases. Oi these
failures, the most common will probably be due to some defect in one
oi the tubes. To iind this detect, check tubes on a reliable tube checkr
er, or by substituting spore tubesv ll the tenure is o short in eiilier
the plate or screen circuits, the tiller resistors and condensers assa
elated with the aircuii lrl question should be checked with a reliable
volt>>ohmeter. To check these circuits it is preterable to use the point
to point system, in which the chassis is always negative, except the
hot side oi the iilament circuit, Which will be negative ii the positive
automobile battery terminal is grounded to the irame oi the car. Then
by applying the positive lead ol the voltohnieter directly to the tube
socket contacts and the negative lead to the chassis, it will Show which
ot the component circuits are at iault, by a total absence ot voltage
or o large difference lroni the correct voltage lroin those given in the
chart ot voltages li a bypass condenser is iound to be at tault re-
place with new condenser Also, check the resistors associated with
the faulty condenser, ii they have been iound to have been hot due
to the shorted condenser, it is best to replace it also to lorestall tature

Other possible loilures. such as open circuits caused hy poor connec-
tions can be likewise located by the above point to point system in
accordance with the chart ol voltages. Open bypass condensers are
apt to cause either a loss ot sensitivity or oscillation ln some portion oi
the circuit. in such cases the iault can be easily located by temporari-
ly connecting a condenser oi known quality in parallel with each unit
that is under Suspicion.

Inten-nlttent or noisy reception is almost always caused by a poor
connection, a bypass condenser intermittently opening iip. or o had
tube, Such iaults are oiten rather diiiicult to iind, bint usually Carl be
located by lightly tapping each circuit element or'component part
with a light rubber hammer Or insulated rod,

In case oi iailure, lt is advisable to check the vibrator, the iuse and
the "Pi" lead connections as the iirSt probable causes. li the set blows
iuses repeatedly. the most likely cause will be sticking vibrator. in
which case the vibrator should be replaced Ii the set upon test shows
to be drawing excessive current immediately upon turning ll'le set on
with a good vibrator and GXSGT in place, the most likely trouble will
be shorted butter condenser,.part No, CrlB. Ii the drain gradually
builds up, the trouble most likely will be one of the iilter condensers,
or one of the byrpass condensers.

POWER

C|4 ANT

(C)John F. Rider

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