RCA VICTOR SRT-403 User manual

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Size
5r' reel (600 ft. )
7" reel (1200 ft. )
SPEED
CHANGE
RECORD
rocK
BUTTON
TONE
RADIO.
P.A.
PltoNo
INPUT
RECORD
CONTROT I.EVEt
INDICATORS
FAST
REWIND RE'NOTE
RECORD CONTROT
swtTcH
PLAY FAST
STOP FORWARD ON.OFF
SWITCH
VOTUME
CONTROL
Figure 1
GENERAL INFORI\4ATION
The RCA Models SRT-403 and SRT-403Q feature fingertip operation for Fast Forward,
Playback, Stop, Record, andFastReverse. Theserecordersaredesignedto record and playback
twotrarkgof materialonstandardwidthrecording tape. Any reel size up to ?r' can be used. Two
neon recording indicators simplify the recording level setting. New recordings can be made on
previously recorded tape since the erase hea.d is automatically positioned wtren the nRecordrr
button is pressed, or the same recording may be played back indefinitely. Recordings can be
made from a radio, television receiver, _or phonograph, in addition to those made dire-gy from
themicrophone. Recordingscanbeplayed back through the seU-contained speakers, or external
speakers may be used by connecting to t}e nExt. Spkr. r' jacks.
The RCA Models SRT-403 and SRT-403Q have two tape speeds, g g/4* and ? L/21, per
second. Using both tracks of the tape the recording time is as fottbws:
RCA VICTOR
MODET SRT-4O3 (Ml-t 5gl7!,
7 l/2* Speed
1/2 hour
t hour
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These unitg are designed to_operate on 60 cycle, 115 volts, AC supply only. Before con-
necting to your line supply, be absolutely certain that it agrees with the -aUove specifications "
3 3/4,, Speed
t hour
2 hours
Manufactured by:
Engtneering Products Dept.
Radio Corp. Of America
Camden, N. J.
This moterial compiled ond published by
sAil5 & CO., lNc., tNDIANAPOLIS,
Copyrighr 1956 . All Righrs Rererved
INDIANA
llATE 1.50 stT 313 FOTDER 9
HOWARD YY.

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BIAS
ADJ.
NCIRMAL
INDICATOR
ADJ.
OVERLOAD
INDICATOR,
ADJ.
Figure 2
SPECIFICATIONS
Size: 10" x L5 7/8" x 14 l/4,,
Weight: 35 lbs.
qpggq: 3 3/4 and 7 1/2 IPs
Reel Capacity: Up to 7" Reel
Rewind Time: 1200' (?" Reel) in 2 3/4 min.
fEernafSpea.t<er Impedance: 3. 2 ohms
ffiEffiinblement: 5Y3, l2AX7, 12AY?, 6AQb (2)
Oscillator Frequency: 60KC
*'*'*G INSTRUCTIONS
Preparation For Operation-
1. Remove the AC power cord, 7" reel of tape,
emptyreeland the microphone from the storage com-
partment.
2"Depress the "Stop" button.
3. Plug the AC cord into a convenient wall re-
ceptacle of the proper rating.
4. Set speed change knob to 7.50 or 3. ?5 as de-
sired.
5. Place "Remote Control" switch in "Off" posi-
tion"
CAUTION: Do not turn speed change knob unless
"Stop" button is depressed.
When the Forward or Reverse btrtton are de-
pressed, the Record and Play buttons are locked so that
Page 2
they cannot be pressed down, with the possibility of
spilling tape. The buttons should always be pressed
down firmly until they latch and the Stop button must
be depressed before changing functions or speeds of
the recorder.
IMPORTANT: Always depress the Stop button when
the machine is not in use.
Speed Change Knob-
Thearrowonthe speed change knob should point
at?.50or 3.75 according to the speed desired. These
recordershavetwo speeds, 7 l/2* and 3 3/4" per se-
cond. The arrow pointing at 7. 50 means the unit will
operate at the fast speed or 7 l/2r, per second.
CAUTION: Turning the speed change knob while the
unit is operating will not change the speed ,
The Stop button must be depressed before
the speed can be changed.
Threading The Tape-
1. Place a fult reel of tape on the left (supply)
spindle, malcingcertain one of the reel slots catch the
protrusions of the pan. Unwind about 14" of tape from
the supply reel.
2. Insert free section of tape into the tape slot.
3. Insert free end of tape into one of the three
slots in the hub of the right (take-up) reel and while
holding the tape in place give the reel two or three
turns until the tape is secured.

Figure 3
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4. The dull side of the tape should always face
away from the operator (rear of unit).
To Record From Microphone-
1. Turn the On-Off Volume control to the right
until a click is heard and allow about 30 seconds for
tfie unit to warm up. The pilot light located above the
Stop Button will glow when the unit is turned on.
2.Insert the microphone plug into the "Micro-
phone" input"
3.Movetherecordlock button (g) downward with
thelefthand. This releases the safety lock which pre-
vents accidental erasure.
4. Depress the "Record" button with the right
hand (while holding record lock button (g) with the left
hand) until it latches.
5. Adjust the "Volumeil control until the rNor-
malil indicator just flashes, while speaking into the
microphone. When the ilVolume" control is advanced
too far the "Overloadil indicator will flash and the re-
cording will be distorted. To prevent overload, lower
the "Volume" control to a point where the ilOverload"
indicator will not flash,
6. The rrTonet' control does not operate during
recording. When recording from radio, set the radio
t'Tone" control for maximum treble.
ToRecord From ExternalRadio. TV. Or phonograph-
l.Insert the phonograph pickup plug into the
"Radiort-P. A. -t'Phonott jack.
2. For radio or TV recording, connectpatch cord,
PartNo. 204215 to the voice coil of the radio or TV
receiver speaker by means of the alligator clips, plug
into t'Radio-P. A. -Phonot' jack.
3. Proceedasdescribedunder ilTo Record From
Microphoner'.
NOTE: Remove patch cord after recording is
completed.
To Use Second Track-
1. Depress the "Stop" button when all the tape
has wound onto t}re take-up reel.
2. Remove reel containingtape and place on left-
hand supply reel.
3. Place empty reel on right-hand take-up pan.
4. Thread tape as previously described.
To Play Recordings-
l.Turn on unit with rVolume" control knob.
2. Thread tape as described under "Threading
The Tape".
3. Set the speed change knob (1) to the speed at
which the recording was made.
4. Depress "Play" button until it latches.
S.Adjust [Volumer and rrTonerr controls to de-
sired listening level.
Page 3

Figure 4
High-Speed Forward Or Reverse-
When it is desirable to play a certain portion
of thetapeover again it is not necessary to rewind the
entire tape. By depressing the "Forward" or "Reverseil
button the tape will advance (or reverse) at a rapid
speed.
Several minutes of normal recording can be
skipped in a few seconds by the I'Reverseil and t'For-
ward" buttons.
Tape Timer-
The tape timer provides complete selectivity
and immediate location of any part of recorded tape .
By turning the indicator to zero when beginning each
reel, the numerals on the indicator will act as a ready
referencetoany desired portion of the recorded tape.
Permanentrecords of this may be kept on the tape box
enabling you to pin-point your favorite selections.
To Edit And Splice Tape-
NOTE: Since it is impossible to edit and splice
onetrackwithoutaffecting the other, re-
cordings which are to be edited should
be limited to one track only.
1. The tape maybe edited by cutting out unwanted
portiong or by joining selections into another sequence .
Announcements may be inserted between selections,
etc. Unused sections of tape can be spliced together
for re-use.
2. Forbestresults, cuttape at a slight diagonal,
join ends together with splicing tape on the glossy side
and trim off any excessive width.
Erasing Recorded Material-
head is automaticallypositioned, erasing any previous
recording before a new one is made. You may erase
material no longer needed, without recording, by de-
pressingthe "Record"button and turning the'T'o1umeil
control knob to the minimum volume position or ex-
treme counter-clockwiee position just before the re-
corder shuts off. One track is erased at a time. To
erase the second track, reverse the reels and repeat
the above operation.
To Use As A Public Address System-
Insert the microphone plug into the "Microphonerr
input jack. Plug in an extension speaker or splakers
if desired and depress the "Record" button. Set the
"Volume" and "Tone" controls to the desired listening
level. A recording can be made at the same time with
a tape placed on the unit in the normal manner.
CAUTION: When using the public address feature ,
see that the microphone is as far away
from the speakers as possible, to pre-
vent "feedback" squeal.
Remote Control Operation-
A socket and switch are provided to allow re-
mote operation up to a distance of 15 feet, either re-
cording or playback. This is accomplished by means
of aremotecontrol cable. Connect attachment cord as
follows:
l.Insert remote control cable plug into remote
socket" Be sure remote control switch on end of cable
is in "Off" position.
2. With control switch on the recorder in "Off"
position start the unit in the regular manner and set
"Volume" control to the proper level.
3" Place control switch on the set to "On" po-
sition. Tape will come to a stop.
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When the record button is depressed, the erase

The recorder can now be operated (start and
stop) by means of the remote cable switch. When
starting the recorder by means of the remote control,
the switch should be rotated to the "Motor" position
andthen a.fter a slight pause rotated to the 'Record-
Play"position. Tostoprecordingor playback, rotate
the control switch directly to "Off" position, pausing
slightly at the "Motor" position"
ADJUSTMENTS
Disassembly Instructions -
1. Remove two screws located in storage com-
partment.
2.Removepush-on type volume and tone control
knobs.
3.Removetwo screws located under volume and
tone control knobs, remove front egcutcheon.
4.Remove two hex head screwg located under
front escutcheon.
S.Removethe wood screwa holding remote con-
trol panel to bottom of case.
6" Lift unit out of case, removing leads from
spealers before removing unit completely.
Record-Plavback Head Adiustment-
To adjust the record-pla.y-head (42) for maxi-
mum frequency response, make the following ad-
justment:
1. Remove the rear escuteheon (12)"
2. Properly thread an alignment tape or a good
recorded tape on the machine.
3. Set the controls as described under "To play
Recordings".
4. To adjust for maximum output of all fre-
quencies, loosen bracket mounting screw (42A) and
rotate bracket slightly until maximum output is ob_
tained. Tighten screws (42A) after adjustment.
To adjust for maximum high-frequency response
onearlyproductiongrip the vertical portion of the re-
cord,/playback head mounting ,bracliet with a pair of
long-nosedpliers. Rock the mounting bracket and re-
cordheadfrom side to side slighily until the maximum
high frequencies are obtained. Bend the bracket with
the pliers to obtain a permanent set at this position.
To adjust for maximum high-frequency response
on_ late production (see figure 2) turn adjusting screw
(428) as required until the maximum high-fr6quency
output is obtained.
Pressure Pad Adjustment-
@1. Remove the front escutcheon (13).
2"Depress the "Play" button" Do not turn re-
corder on.
3. Use a pencil type postal scale and check the
amountofpressurenecessaryto just pull the pad away
from the tape. The test should be made on the end of
the pressure pad mounting spring (49). Adjust the
pressure pad for I 3/4 oz. + l/4 oz.
Hum Control Adjustment-
It is very important for recording purposes that
the hum control be correctly adjusted" Hum that is
present during recording will be amplified during play-
back.
To set the hum control turn the unit "On" and
allow the tubes to warm up, advance the volume control
to approximately mid-position and adjust the hum
control (R3) for minimum hum.
(a)The record head pressure pad is adjusted
by the locked adjustment screw (41).
(b)The guide post pressure pad (40) is adjusted
by bending the pressure pad spring. It must be adjusted
for minimum pressure against the tape"
4. After the adjustments are made depress the
"Stop" button and replace the front escutcheon.
Erase Head Adjustment-
1. With tape properly threaded, turn recorder
onanddepress the "Record" button. Allow tape to run
for a few geconde then turn recorder off, but leave
"Recorder" button depressed.
2. Withthe escutcheons removed check the erase
head (44) to see if it is parallel with the tape.
3. Check to see if the top edge of the tape coincides
with the'top end of the diagonal slot in the erase head
(junctionoflong diagonal slot and short vertical stot) "
Toadjustlevelof tape, loosen set screw (33), see ex-
ploded view, and rotate tape guide post (34) to move
tape up or down. Tighten set screw (33).
4.Afterthisadjustmenthas been made, eheck to
see if the tape moves forward approximately 1/64" when
the "Record" button is depressed. If not, loosen the for-
ward adjustment screw (44A), see Figure 2 and turn
the screw in or out as required to obtain this 1/64r'
movement. Tighten the lock nut.
Brake Shoe Adjustment-
1.In order to adjust the brake shoes, the com-
plete mechanism must be removed from the carrying
case and the speakers disconnected.
2. With all push buttons in the up position the brake
shoes (68) should clear the drums by approximately
1/8".
3"Depressthe "Stop" button while observing the
brake shoes. Both brale shoes must contact the drums
at the same time and with equal pressure.
4. The adjustment is accomplished by bending
the spring arm (6?).
Adjustment For Slow Take-Up Reel-
There are some instances where the spring drive
belt (21), see Figures No. 2 and No. 6,{, stretches
afteraperiodof time. When this happene, the take-up
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Figure 58. Exploded View of Parts Below Baseplate.
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torque will be insufficient to wind tape properly onto
the takeup reel. In this case, the belt should be re-
placed as follows:
Remove rear escutcheon (12). Remove take-up
reelpan(5). Withttre "Stop" button depressed, remove
oldspringdrive belt from around pressure roller (b6)
andlift belt clear of recorder. Install new belt by re-
versing the above procedure.
Bias Adjustment-
Turn the recorder on and depress the "Recordn
buttonl useno tape. To determine if the bias is within
satisfactory limits without dismantlingthe unit, merely
connectaYTVMfromthe top lug of the recording head
tochassis. If?5 io 100volts are present no adjustment
is necessary.
If the readings are outside of this range, proceed
as follows:
l.Try new l2LY7, L2A)d7, 6AQD and by3.
2. If still not within range, remove the chassis
shield and connect a low capacity VTVM from test
point '4" to chassis. Use low scale. Adjust trimmer
M8 for maximum reading. Adjust trimmer M? to obtain
a reading to 2.25 volts" This provides the optimum
in performance.
Neon Record Level Indicators
The neon record indicator firing level adjustment
is only required if a neon bulb is replaced. The two
neon indicators are adjusted for correct firing level
by means of two trimmer capacitors, one for each
indicator.
To adjust indicators proceed as follows:
1. Turn recorder on an depress "Record" button.
2. Connect a short jumper lead across the bias
oscillator coil, L1 (short out ttle coil to disabte the
oscillator. )
3. Connect an audio oscillator, set at 1000 cycles,
into tlte microphone input jack. Output of audio os
cillator shouldbeapproximately. 01 volt. (A1 volt out-
put level may be used with a 100 to 1 reduction pad of
resistors inserted between the audio oscillator and
the microphone jack).
4"Connect probe of low capacity type AC VTVM to
test point "8" (junction of two 330KO resistors, R32
andR34, mounted on a terminal strip near the volume
control).
S"Adjust volume control to obtain a reading of
36 volts on VTVM and leave control set and VTVM
connected.
6.Disconnect shorting jumper from across bias
oscillator coil.
?. Adjust "Normal[indicator trimmer M9A fully
clockwise and then turn slowly counterclockwise so
that upon loosening the trimmer the 'lNormal" bulb
barelylights. This adjustmentmust be made loosening
the trimmer.
8" Short out the bias oscillator coil.
Page 8
9" Increase volume control to obtain a reading of
88 volte on the VTVM.
10. Remove short from bias oscillator coil.
11. Adjust I'Overload" indicator trimmer MgB as
described in step "?" for just barely lighting the "Over-
load" indicator bulb.
IMPORTANT: Do not readjust the recording biag
oscillator after setting the indicator
light adjustments.
TROUBLES
Push Buttons Fail To Latch Into Position-
1. Lock plate spring (28) loose or broken, re-
sulting in the lock plate not being held against tlre hinge
bracket (27)"
Fails To Erase-
1. Spring (38) loose or broken, resulting in the
erasehead (44) not being pulled forward to engage the
tape.
2. Erase head not aligned properly" See "Erase
Head Adjustment""
Speed Variation Or "Wow-
1. Checkt}re capstan (20), pinch roller (86), iiller
wheel(131), motorpulley (142), andflywheel (11! for
oil or foreign material on these driving surfaces. Clean
these parts with a good cleaning fluid.
2. Checkmotorpulley(142) to see if it is secured
to motor shaft.
3" Check idler tension springs (133); see if ttrey
are holding idler wheel ( 13 1) in firm contact with motor
pulley (142) and flywheel (112).
4.Idlerslideptate (12?) binding on slide bushing
(126), preventing idler wheef (131) from making positive
contact with the motor pulley and flywheel.
No Fast Forward Or Reverse-
l.Idler lever tension spring (64) may be loose
orbrokenl if so, idler lever (69) will not be actuated.
2. Check idler drive belt (?1) to see if it is pro-
perly connected.
No Drive On Record Or Playback-
l.Idler tension springs (133) loose or broken,
thereby not holding idler wheel ( 13 1) in engagement with
motor pulley (142) and flywheel (112).
2. Idler slide plate (127) binding on slide bushing
(126), thus preventing idler wheel (131) from moving
forward.
Tape Fails To Wind O! take-Up Reel During Record
1. Reel drive spring (20) loose or broken. See
"Adjustment For Slow Take-Up Reel',.
2. Brakedrumshaft (113) binding. Clean foreign
matter from bearing surface.