Howard Radio Co. 240-1 Schematic

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Product Information:
Model:240-1
Manufacturer:Howard Radio Co.

Schematics Content:

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Page 1:

HOVVARD PAGE 9-7
FOR NOTES AND ALIGNMEINT
SEE INDEX
MODEL 240 Su.; -l
MODEL 240 2.
(C)John F. Rider, Publisher

Page 2:

PAGE 9~8 HOWARD
Ph ,I Par
?"? '?'='>> *= HOWARD RADIO co.
Timer Data
CONNECT AERIAL, POWER SUPPIV AND TURN CN VOLUME IEFBRE STARTING STATION SEYYUP
_ _ SET-UP INSTRUCTIONS
F|n?1 _ Select button by number that w|II tune desired station meeord- fm, _ N," ,,,_,_,, ,he ,4i,,,|,,..,,? 4;,,?|y .Len nnril nleetrie eye
lf\9'?I'?'1U?"?Y vs- l=uN?r~= lr =|\?v>>\ ll=?v?_ xhaws maximum dotlsdinn, then slightly re-mdiust rea sdnmnmenf
Szcotm - Depress the button selected, then ediust red adiustment (be for maximum aye deflection. _
sure to adiust the mdiuxtment having the same number as the de- Founmr-Insert the stetion :all latter tab over _button number |uxt
pressed button.) Move this adiustment until desired station is heard. selected. Repeat this procedure for the rememmg buttons.
Station serine. wan. wan r_.e.,._.=y 11 no uc, rrmmfen none.. 1, 3, ._ 4 _.__ e. _.ne me ne .azon_._..n re .e.:._ new nzosnly 1? einen oy. re. n_.__am__m dn1._>>:em_wan_ne jx
sono" 3 ir eoefenee er. :ren or emi, me no sdimnmen above No 311 news mmm wsu "neue mem me _:nn ...A snnnee an .,=_.??r_.e>> ever ne. J. neon nb by sndnno m
eomn in The eeimnnenr dafeeny obey. me _ee en. ._ sdi-ned ref nmnmmm ey- osrleonen, else. wan r1ne.r_>>1e_
FIRST - Do not try to txland the ad|uxt|Mn|s beyond their Irequlncy ri|ing_ FOURTH - Chuck ldiuxtlnents ocqxionally Int ltwlimum diflklion oi rye, while retaivir vs
mum-no elseneox bor ' d' 1 1 in n ko nm. edmnmonr number ser- _" _ '_ '_ ' _ _ _ _
respond? to bullon nurzlgzrfngnlgizxnzx:inlruihriwrlmnnar :nu mn you ro mixadiusl sdimn~ ""'?" """'?' "' ""' ""'?" """' '""" '" "' ?""""""' ?'" "' """"" "'?""""
asvmcnn-:nn PARTS um mm: 1.151
node1s 240-1 and 240-2
PART usr cmculr Pm LIST cmcurr
No. PRICE n crumou women & mics nmcnxrmuu LOCATION
32-sae $1.30 Coil - 1ez 1.0. Assemmy, como1see_ _ _ _ L1 4s-282 $0.16 Condenser - .0000 md. Mica _ _ _ _ _ _ _ 010.011
:sz-ees 1.30 cm - 2nd 1.0. Assembly, come1eee_ _ _ _ 12 .1s Condenser - .oooos md. mes. _ _ _ _ _ _ 012
2.111 .40 co11 - dnesnne. _ _ _ .._.._.._. ze-as; .vs con+.no1 - volume ..... _ ...... _
2011 A-O Coil - Oscillator . _ _ -AA..... _ 14-275 -95 Control - Tone and Switch >> o - - . _ . o
25-255 L25 Condenser - B-4 H.fd. 400 Volt, Electro- 1-290 -35 Cord - Line and Plug. - . . - ~ . . >> . _
52-252 ~Z5 Cvndenssr - Trlnmer- 2 Plate Hvdel 240-1 A,I|J,K, 22-490 ~1O BIICISOH IDT BUBCIDI1 SSIBCKUP ~ o ~ . - . e
35-262 -2_5 condenser - 'mmmer-s Flats node1 340-1 B 15-480 .10 Knob - moex esxrenee _ _ _ _ _ _ _ _ _ _
34-362 .as condenser - 'rrxmmer-4 mere nodsl 24o~1 0,11 .12 aesxscor - 2_5 Ohm 1/2 wana. _ _ _ _ . _ _ m
55-262 .25 condenser - 'rrxmer-5 more node1 240-1 1:,r,c .12 nesxsnor - 75 onm 1/2 were. _ _ _ _ _ _ _ nz
36-262 _so condenser - 1'r1msner~o Plate I10de1 240-1 II .12 Resistor - zoo Ohm 1/as Matt _ _ _ _ _ _ _ mx
as-zsz .40 condenser - Tnmer - Dual Hndal 240-2 cn .12 aesmor - 15,000 onm 1/2 user. _ _ _ _ _ nd
do-2s2 .40 Condenser - 'rrxmmer - 1>us1 Model 240-2 nr .12 nesdseor >> so,00o Ohm 1/2 usoe. . _ _ _ _ as
41-262 _do condenser - Trimmer - Dual Model 2d0>>2 cn .12 nes1seer _ 200,000 onm 1/:_ Batt _ _ _ _ _ ne
421-262 -55 Condenser - Trilllner - Dxml H0461 2,40-2 AB -12 Resistor - 500,000 Ohm 1/3 Watt >> _ - _ o R7
4-I5-262 -40 Condenser - Trinlwr - Dual H0661 2/40-2 OP -12 Resistor - 1 Hegohm 1/3 Hath . - r >> - s RB,R,9
44-262 .40 Condenser - Trillllwr - Dual Model 240-2 HN 2744 ~15 Soflket - 4 Hong. 1 >> e - >> . - . _ . _ _
46-262 |35 Condenser -`T1"illls!' -Dunl HDCISI 240-2 XJ 2747 -15 Socket - 7 Prong. - - - . _ _ _ . . . e o
.10 Condenser - .1 nm. doo Volt. _ _ _ _>> _ _ 01,02 e-7-12 .15 Socket - 4 Prong, speaker _ _ _ _ _ _ . _
.1e condenser - 101 nrd. doo vo1e _ _ _ _ _ _ ca 9-917 2.50 smcen - Pusn-rmcmn, se1secor_ _ _ _ _ _
.1s condenser - .02 md. 200 vo1r _ _ _ _ _ _ cs,ce 9-771 _os 'n1n1ng Eye Socket sno como _ . _ _ _ _ _
_zo condenser - .02 nm. nou1ded_ _ _ _ _ _ _ cv 27-935 2.75 'rrensrormsr - Model 240-1 fur ao Tube _ _
-16 condenser ~ .05 nrd_ 200 Volt _ _ _ _ _ _ ce 39-#938 2~7S Transformer _ Model 240-2 for 1V -1-moe _ _
_1e Condenser - .004 md. doo Qolt. _ _ _ _ _ m` dz-am 4.00 Speaker _ 51' mmm plug __.._ _ _ _ _
nom when ordering spesxer parts such ss cone, cmnsrormer or one r1e1d It 1s necessary uns: une number on one back or me sneaker be
me dn_41>r1oN or 'mn sm ron use WITH m0Noo1u1>1-1
cue or me mex or :ne cnsss1s there exceeds enrse lugs ss shown rn msgrsn ng. 1.
For pnonompn use, one Jumper is removed and s s1ng1e pole, douo1s throw sermon 1s connected ss shown ln ng. 2. The exon-up lame
from the pick-up are eonneotsd no Nos. 1 and 2 :erm1ns1s, men the overall sn1e1d grounded to nn. 2 :emne1.
PRICES ARE SUBJECT TO CHANGE' WITHOUT IDT ICE RAD\0
(C)John F. Rider, Publisher

Page 3:

g' o L DESCRIPTION Amo or snomwxvs B 5.5 To le M. c. A L., tg tg ?11
ng ___?N0DEL 36 15 an B tube Seb hevine Chree bands. wverase being First check the position or the dial nand by rotatlng the condenser 5 ag H E E; 'F
. to lvoo kc, 1.7 to 5-5 "C and 5`5 to 13 Mc' There "9 Separate oe- snare to the left to run oapacmy. at this point the oral hand should a g on >>-1
cillators and R.F. coils for each d. For the broadcast band only a be straight across in l1ne with the lines dividing the scale ln half. If ? O: 02 N 32
31 preselactor coll is used, belng tuned by the back section of the gang the hand is off posltlon lt can be lined up by removing dial glass and g :V W S S
E condenser. setting hand with screw ln center of dlal. *-' Z ` | E
3 The tIu'ee I. F. stages are tuned to 465 KC followed with the conven- 1. Set the test o clllator to 17 megacyoles. 3 0 3
? 5101141 M0591 S-YlD11!10T', and HHS19 Output circuits. 2. Turn wave band switch all the way to right for highest SM. band, and gf 8- 01 5; >
set dial hand to 17 M. C, 'Q M sh
_UE MOD 3 ?18, :ig are the s chassis (the model numbers refer to 3. Peak trimmer condenser of the osc1llator coil to resonance w1th 17 M. O 55
2 different Cabinet Styles). This ten tube Set has a similar R. F. and C. fed into antenna. T6 E | U
V I. F. coll system except that the preselector stage on the broadcast band 4. Ad,]ust antenna trimmer to same frequency after the above mentioned g N
F' includes the 6 K'7 tube. The output to push pull beam power", the 6.156 oscillator trimmer has been set. T2 g
Z' being the inverter tube. uw '
=. _ NOTE: After adjusting the two high bands at 17 rnegacycles and 5 megacy- "'
Q THE MODEL 240 series 1 and 2 is strictly a push-button tuner having cles the test oscillator input to antenna should be increased and re- SL
vg H0 Zen! C0l'l39!\S9I'~ The elsht 171?Sh~b\l\2'D0n SKMIOH SSISOSOFS Horhplebf-2 the csiver dial advanced to .9 megaoycle lower and note if test oscillator (_,
ground circuit of the oscillator and R. F. tuned condensers previously signal is heard. :-
set to whatever frequency desired. The eight circuits cover the complete In case there is no response the osclllator trimmers have been pulled '?
r of the broadcast band from 540 to 1750 KC. The instructions for down too tightly. The trimmers should be released until this condition 2
the set-up are shown on separate page of this manual. exists then go back to original point of ali nt - reduce antenna input Q
voltage and correct the trimmer adjustment. o ._, r
The model l used the 80 tube for a rectifier and the model 240-2 5'
uses the lv type tube. EXAMPLE: The r?colver has been adjusted to 17 megacycles. Tune receiver D,
to approximately 16.9 M. C. 3
refer to the part list. when ordering specify Increase oscillator signal by 'opening up" the attenuatcr. Move the m
serial er of set as wall as the part number. dial back and forth at 16.9 M. C. U3 O
V If no signal 1s heard, let oscillator tri r ctr until it is heard Qi A
FOR CIRCUIT VQQAGEQ refer to the charts sham in the following at 15.9 M. C. = <1
es for models 568 and 318. The voltages for the model 240 are shovm Reduce signal voltage from generator, go back to l'7 M. C. and slight- g
on the schemtlc dlagr' . ly correct this last trimmer adjustment. >
The same applies to the 5 11. C. adjustment. "' gg
THE ALIG PROCEDURE Q at U
The all ent procedure for the 365-318 models 15 given in the f01~ E .4
lowing pages. we est, however, that no attempt be made in changing ALJG OF POLICE BAND 1.7 T0 5.5 I'I.C. Si g Z
the trimmer adjustments unless it is found t a. change is necessary. '?
l. Set the test oscillator to 6 megaoycles. 2- ? U*
we suggest in case of trouble the tubes, especially the 6.150 and 2. Turn wave band switch to the middle position for Police Band, and set 2; G, U
the SP5 types,be checked. dial hand to 6 N. C. er 5 \_'
3. Peak trimmer condenser T5 of the oscillator coll Fig. 4 to resonance
The Only Other trouble that m1$ht Oocur 15 in 03898 OI extreme low with 6 H. C. fed into antenna. O
A. C. line voltage of 100 volts or less, by which the oscillator plate 4. Adjust antenna coll trimmer T5 to some frequency after the above men- 3
vol e might drop to too low a potential. tloned oscillator trimner has been set. E "oe 3 ? Q
for the model 368 will be abbut B 170 12 THE ALIG OF 'THE ROAD ? on l" Q
mlcrovolts, mdel 318, about 2 to 4 mlcrovolts and the model 240, 15
to 30 mlcrovolts. 1. Turn wave band switch all the way to left and dial d set to 1400
KC (the top scale).
2. Peak oscillator trimmer T4 to 1400 KC and antenna trimmer Tl to same {\> ,_,
I. '1'I~!E LF. STAGES frequency. Likewise C15 trimmer on the gang condenser. $3 v-1 cn
3. Set dial hand T50 600 KC and adjust Osclllabol' padding condenser T5 5 5
The intermediate frequency stages are aligned in the usual manner by to 600 KC. ' 5 Q .91
feeding 465 K.C. into the grid of the mixer tube SA7. 4. Recheck dial at 1400 KC as in number (1) and (2). g gf gf
5. Points in the middle or the dial may be checked and it necessary the w
The two trimmers in each of the LF. c should be very carefully plates of the front section of variable condenser be bent for
peaked to resonance as they are very critical and will greatly affect the all ent.
performance or the set. NOTES ,.. E
Always use as low an output ae possible from the signal generator "1 :: t E
when maklng the various adjustments, 1. Seal all trimmers after their final adjustment. ? ? EF, 5
The senelclvuy or the 1.r. system alone will be round to oe between 2- Be Sure that the settings are heme made to the true fund ntal 57 Q U' ?
15 and 20 Mlcrovolts, signal from the oscillator and not on a ha n1c or image frequency.

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