Patterson Radio Co. 375AW Schematic

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Product Information:
Model:375AW
Manufacturer:Patterson Radio Co.

Schematics Content:

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Page 1:

PATTERSON PAGE 8-1

ALIGNMENT OI" INTERMEDIATE AMPLIFIEH-Connect the grid
ot the vacuum lube voltrneter to any point on the AVC hus and
the ground lead oi the vacuum lube voltmeter to ground on the
chassis. Remove grid clips irom BB7-second LF. tube. SDS-ttrst
LF. tube and 6A7-detector-oscillalor lube. Place oscillator in
'operation on 458 KC. Apply output oi oscillator to grid ot 637 and
adiust trimmers on i.i~`. transiormer at right oi SB'I until loudest
sound is heard in speaker and meter on vacuum tube vollmeter
swings iarthest toward Replace cap and shield on 687 and
apply oscillator signal to grid oi SDS. Adiust trimmers on i.l-`.
translorrner to leit oi SDS as described above. reducing oscillator
output-ii nesessary to obtain a good readable swing on meter.
Alignment ol 1st l.l-'. being completed replace clip and shield on
EDB. Apply oscillator output lo grid of SA? and adlusl trimmers on
LF. transformer. located at right ot 6A7 tor maximum swing towards
sera ui vacuum tube voltmeter. ii these instructions have been
careIuIIy IolIowed. the intermediate frequency amplilier will be
properly aligned.

CAI-IBBATION OF BROADCAST BAND-Turn switch to broad-
cast position. With vacuum tube voltmeter connected to AVC hus
as described under intermediate Ampliiier alignment, place service
oscillator in operation at HUD KC. Turn let dial to 1400 KC and
adiust oscillator trimmer tor resonance as indicated by farthest
swing toward "0" oi vacuum tube voltmeter. New adiust service
oscillator to 600 KC. Turn set dial to 600 KC and adiust law tre-
quency pad lor resonance as indicated by vacuum tube voitmeter.
Set service oscillator again at 1400 KC and turn set dial ta HDD
KC. Readlusl oscillator trimmer tor resonance as indicated by
vacuum tube voltrneter. Without moving dial setting. adiust detector
and ILF. trimmers tor maximum swing toward

CALIBBATION Oi" ZND BAND (1.6-4.5 Megacyclesl-Turn switch
to second band position. 'l'urn let dial to 4.0 megacycles. place
service oscillator in operation at 4.0 megacycles and adiull set
oscillator and detector trimmers to resonance as described under
1400 KC adluslmenl oi broadcast hand. (Note-On some queh

(C)John F. Rider, Publisher '

MODELS 75Aw,175Aw
PATTERSON RADIO CO. 275AW,575AW
Schematic ,Alignment
W... ` IF PEAK *Tar/wa _

Models 75AW, 175AW. 275AW 375AW

Frequency bands reierred to tn the iollowing instructions as:
3rd Band-4.542 Megacycles
4th Band--11 -10 Megacycles

PART VALUI 'All'

l l m Bulls C l mv.

K I Hmm onus C 9 m1.

I" m." a Cid (WL

'USE OF DOUBLET

Remove link on antenna
terminal sh'iP on back ot
chassis. Connect doublet
leads to terminals A and D.
The usual ground connection
may b. und n "mimi G
but link connecting D a'nd G
must always be removed

when a doublet is used.

A ward ol Caution concern-
ing the ule at doublet anten'
nas is deemed advisable. A
properly "grae-red and in-
stalled doublet antenna il
very efficient lor short wave
:sc-prion but uni." prep-fly
"gina-ed will gin "ry
poor results.

detector trimmer is unnecessary and is omitted irom chassis

CALIBRA'I'ION 0F 311D BAND (4.5-l2 Megacyclesl-Turn switch
to third hand position. Place service oscillator in operation at 12
megacycles. 'l'urn set dial to 12 megacycles. Adiust oscillator trim-
mer until signal is heard loudest and then adiust detector trimmer
lor greatest vacuum tube voltmeter swing toward "0".

CALIBRATION 0F 4TH BAND (Il-20 Megacyclesl-Beiore at-
tempting any calibration of this band it will be necessary to deter-
mine the oscillator tracking. Some models were produced in which
the oscillator beats SLOWER than the incoming signal. This is not
the usual mode oi operation but was used tor more uniform track-
ing. in other production series the oscillator beats taster than the
incoming signal. which is the usual method oi operation.

To determine which model your set is. proceed as follows:
Place service oscillator in operation at 15 meqacycles. Tune signal
in on set. ii oscillator BEATS SLOWER. the real signal will come in
at 15 megacycles and the image will come in at 15.915. i.e. The
image will be almost 1 meqacycle iaster than the true signal.
It oscillator BEATS FASTER, the real signal will come in at 15
megacycles and the image will come in at 14.084 megacycles, i.e..
almost 1 megacycle slower than the incoming signal. Alter having
determined which oscillator tracking is used in your set be sure
to keep this setting. i.e.. either taster or slower. as determined.
throughout the entire band.

Place service oscillator in operation at 20 meqacycles. 'l'urn set
dial to 20 meqacycles. Adjust oscillator to a point taster or slower.
os determined from above. where signal comes ln loudest. Now
adiust high frequency trimmer until vacuum tube voltmeler shows
greatest swing toward Now. place oscillator in operation at
12 megacycles. Turn dial slowly toward 12 megacycles until TRUE
'SIGNAL is heard. Adiust low irequency pad (the one on the end
oi the chassis' which has '/4 megohm resistor across it) until the
vacuum lube voltrneter shows greatest swing toward sero. J

Page 2:

PAGE 8~2 PATTERSON
MODEL lOSAW

SchematiC PATTERSON RADIO co.

MODEL }ms>>w

(C)John F. Rider, Publisher

Page 3:

PATTERSON RADIO CO.

(C)John F. Rider, Publisher

PATTERSON PAGE 8-3

MODELS esA'Jf-A,1asAw-A

Schematic s

Model 15 AW-A

Page 4:

84 PATTERSON

MODELS 75AW-A,

PATTERSON RADIO C0.

SET LAYOlrl-Plguxe 2 .ham the layout o! coil. and trimmer

ll ldantical lot both .em and eight-tubs modell.

Looking m the bottom of the chaui.. the section ot th. band

lt Willjn nolsd that the trimmer condenler [or meh band ll
than" "Fitch nmol! the front of Ili. chmil switch!! the antenna-

locuhd dinctly On the coil torminull cmd th. tfimmlf to! thi

broadcast bond-pm il lncaiad on top ol tho variable mdonlir.
dltldnr coil.. The Nm' section Iwitchel the oscillator plc'lo and

grid coils and in addition "killl" the nillnt hmlnq cdiustmsnt on

all except the bmadeult band.

(C)John F. Rider, Publisher

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