PENTRON NL-1S User manual

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GENERAL INFORMAT ION
NL-z, NL-2S, NL-3, and NL-3S are.designed for making
and pl either 3 3 /4 inches per second or ? L/2 h;nes per second.
Recor ull length recordings can be made on a single reel of tape.
Any size reel up to 7" may be used on these machines and therefore arecording time of 3 hours
or more can be had, depending upon the tape thickness.
Models TM-l and TM-4 are ldentical except for the sterophonic heads used ln Modtri
TM-4.
These Models are for operation on a 60 cycle 105 to 120 volts, AC supply only. Before
connecting to your line supply, make certain that it agrees with the above speciiications.
Manufactured b!:
Pentron Corporation
777 South Tripp Avenue
C h icago 24, I lli nois
fhis moleriol compiled ond published by
& co., lNC., INDIANAPO[15,
c366
Copyright 1958 All Righrs Reserved
INDIANA <t1
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HOWARD w. sAts
DATE 9 - 58

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TABLE OF CONTENTS
Page Page
General Information I Mechanical Troubles And Probable Remedies . . . 16
Specifications 3 Electrical Troubles And Probable Remedies. . . . L1
I\rnctions of : Schematic Diagram - Model NL-l . 19
Controls, Indicators, & Switches n *n"-atic Diagram _ Model NL_2 . ZL
operating Instructions t ,"n"-atic Diagram - Model NL-3 . 22
Mechanical Adjustments 8 M""hanical parts List _
Parts Replacement. 10 Models TM-l , NL-1, NL-z, & NL-3. 27
Lubrication ......13 ElectricalPartsList-ModelNL-1 . 23
Cleaning 13 Electrical Parts List - Model NL-z . 24
Exploded View Of Parts Above Mechanlsm Plate L4 Electrical Parts List - Model NL-3 . 25
Exploded View Of Parts BelowMechanism Plate. . 15
SPEC IFICATIONS
TM-I Transport Mechanism
SPEEDS: Record and playback, T l/2 and 3 3/4 ips.
FAST FORWARD: Complete wind of a 7 inch reel in
?5 seconds.
REWIND: Complete rewind of a ? inch reel in 90
seconds.
FLUTTER: Under 0.470 at7 L/2 ips.
Under 1 %at3 3/4ips.
MOTOR: Heavy duty 4 pole, shaded pole motor, dy-
namically and individually balanced.
CONTROL: Single rotary control for PIay, Record,
Fast Forward, and Rewind.
TM-4 Transport Mechanism
The TM-4 mechanism is the same as TM-1
except that it uses a stacked "stereo" head assembly.
NL-I Recorder
FREQUENCYRESPONSE: 40to 1t000cpsat ? L/2ips;
40to ?,000cpsat 3 3/4ips.
POWER OUTPUT: 4 watts.
SIGNAL TO NOISE RATIO: 45 db.
"RECORD-PLAYBACK IIEAD" Ilave replaceable
andDOUBLE GAPERASE HEAp: 'pole pieces.
RECORD LEVEL INDICATOR: Neon type.
INPUT JACKS: One for microphone or magnetic phono
cartridge; one for radiq TV, and cry-
stal or ceramic phono cartridge.
OUTPUT JACKS: One for external amplifier or head-
phone monitoring; one for external
speaker.
TUBE COMPLEMENT: One each 6J?, 6SL?, 6X5, and
6V6.
POWER CONSUMPTION: ?0 watts, full load.
DMENSIONS: 14'W x 1?"D x 11"H.
WEIGHT: 25 lbs.
Mechanical Specifications are the same as for
.TM-1 as mentioned above.
NL-lS Recorder
The NL-1S is the same as Model NL-1 except
that it uses a stacked "stereo" head assembly and a
"stereo" preamplifier.
NL-2 Recorder
FREQUENCY'RESPONSE: 40 to 13,000 cps at ? L/2 ips;
40 to ?,000 cps at 3 3/4 ips.
POWER OUTPUT: 5 watts.
SIGNAL TO NOISE RATIO: 48 db.
"RECORD-PLAYBACK HEAD" HFve replaceable
andDOUBLE GAPERASE HEAD: pole pieces.
RECORD LEVEL INDICATOR: Magic eye.
AUTOMATIC INDEX COUNTER,
INPUT JACKS: One for microphone or magnetic phono
cartridge; one for radio, TV, andcry-
stal or ceramic phono cartridge.
OUTPUT JACKS: One for external amplifier or head-
phone monitoring; one for external
speaker.
TUBE COMPLEMEITIT: One each 6J?,6SL?, 6X5,6V6,
and 6E5.
POWER CONSUMPTION: 80 watts, full load.
DIMENSIONS: 14"W x L6 3/4"D x 10 3,/4"H.
WEIGIIT: 29 lbs.
Mechanical Specifications are the same as for
TM-1, as mentioned above.
NL-25 Recorder
The NL-2S is the same as Model NL-2 except
that it uses a stacked "stereo" head assembly and a
"stereo" preamplifier.
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Later Production TM-1 Models Are Equi with Record-Play and Double Gap Erase Heads.
Figu re I . Top View 0f TM-l With Escutcheons Removed.
NL-3 Recorder
FREQUENCY RESPCNSE: 40 to tS,dOO cps at 7 l/2 ips;
40 to ?,500 cps at g 3/4 ips.
POWER OUTPUT: 10 watts, push-pull.
SIGNAL TO NOISE RATIO: 50 db.
"RECORD-PLAYBACK HEAD" Have replaceable
andDOUBLE GAPERASE HEAD: pole pieces.
RECORD LEVEL INDICATOR: Illuminated VUmeter.
AUTOMATIC INDEX COUNTER.
INPUT JACKS: One for microphone or magnetic phono
cartridge;one for radiq T{ and cry-
stal or ceramic phono cartridge.
FUNCTIONS OF CONTROLS,
Speed Control
Tape speed is controlled by moving the Speed
Control Lever (26) either to the right or left. When
the lever is in the right hand position the tape speed
will be 7 l/2 ips. When it is in the left hand position
the speed wiII be 3 3/4 ips. Change of speeds should
neutral position.
The mechanical action during a speed-change
operation is as follows: A notch in the Speed Control
Lever (26) engages the Speed Control Sector (25) so that
when the Speed Control Lever is moved either to the
left or right, the Speed Control Sector and the attached
Shaft (6?) or (69) are moved up or down, accordingly.
The Idler Wheel (94) and Idler Bracket Sub Assembly
(95) are attached to the shaft assembly and move up or
Page 4
OUTPUT JACKS: One for external amplifier or head
phone monitoring; one for external
speaker.
TUBE COMPLEMENT: One each 6J?, 6SL7, 6X5, 6V6,
l2AU7, & two 6AQ5's.
POWER CONSUMPTICN: 110 watts, fuII load.
DIMENSIONS: 1? 1/8"W x 17 3f 4"D x 11"H.
WEIGHT: 35 Ibs.
NL-3S Recorder
The NL-3S is the same as Model NL-3 except
that it uses a stacked "stereo" head assembly and a
"stereo" preamplifier.
I ND I CATORS, AND SWITCHES
down with it,thus allowing the Idler Wheel (94) tocon-
tact one or the other of the two steps on the Motor
PuIIey (99). When the Speed Control Lever (26) is in
the left hand position the Idler Wheel (9a) is in the up
position and contacts the smaller step of the Motor
Pulley (99). A tape speed ot 3 3/4 ips results. WIen
the Speed Control Lever (26) is in the right hand pos-
ition the Idler Wheel (94) is in the down position and
contactsthe larger stepof the Motor PuIIey(99). This
results in a tape speed of.7 L/2 ips.
When the Speed Control Lever (26) is moved to
the right to select a tape speed of.7 l/2 ips, the down-
ward movement of the Speed Change Shaft (69) causes
the Speed Equalization Switch (M3 on Model NL-2 and
M7 on Model NL-3) to open in order to obtain correct
equalization for the ? l/2 ips speed.

Figure 2. Top View 0f NL-I
Rotary Control
The Rotary Control (3) governs the mechanical
operation of the transport mechanism. When the
Rotary Control is turned to the left, or in a counter-
clockwise direction from the neutral position, the
mechanism is placed in Fast Forward operation. When
the control is turned in a clockwise direction from
neutral the mechanism is placed in Fast Rewindoper-
ation. To place the mechanism in PIay or Record
operation the Rotary Control is pressed downwards
from neutral and turned to the right.
CAUTION: Do not attempt to turn the control to the
left while it is depressed.
The idler wheel is automatically disengaged
when the rotary control is in neutral position.
Action of the Rotary Control Shaft Assembly (49)
can be considered under two conditions; (1) with Rotary
Control not depressed, and (2) with Rotary Control
depressed. Under the first condition a stud in the
upper surface of the assembly engages a slot in the
Wind and Rewind Slide Plate (47). When the Rotary
Confrol is turned to the right for Rewind operation the
Slide Plate (47) is moved to the left by the action of
the stud. As the Slide Plate moves, a shaped slot which
engages one end of the Tie Bar Assembly (64) causes
the Tie Bar to move back, pushing against the Equal-
izer Bar (88) and thus tightening the Feed BeIt (101).
The sliding action of the Slide Plate also moves the
Idler Release Lever Assembly (48) by means of a stud
in the same assembly (48) which engages another slot
With Escutcheons Removed.
in the Slide Plate (47). This movement of the Idler
Release Lever Assembly allows the Idler Spring (91)
to puII the Idler Wheel (94) intocontact with the Motor
PuIIey (99) thus driving the Flywheel (?6), the Feed
Belt (101), and the Feed ReeI Spindle (89).
A third effect of the movement of the Wind and
Rewind Slide Plate (47) is the application or release
of the reel brakes. When the Rotary Control is in the
neutral position the bottom stud on the Control BaII
(40A)is in avertical positionand the studend projects
through slots in the Slide Plate (47) and the PIay and
Record Control Cam (42), and fits intoa dimple or de-
pression in the Control Spring Plate Assembly (6b).
The cross arm of this assembly (65) bears against the
Brake Arm Adjustment Screws (7?) and (77A), applying
pressure to the brake arms, which in turn hold the
brake shoes against the reel seats. As the Wind and
and Rewind Slide Plate moves to the left for Rewind
operation it pulls the control ball stud out of the
dimple so that the Control Spring Plate moves up and
releases the brakes. When the Rotary Control (3) is
returned to neutral a reverse action takes place and
the brakes are reapplied. The action of the control
baII stud is such that the brakes are applied first to
the reel from which tape is being removed, thus pre-
venting any over run tape spilling.
When the Rotary Control (3) is turned to the left
for Fast Forwardoperation,theWind and Rewind Slide
Plate (47) rnoves to the right and causes the Tie Bar
(64) to puII the Equalizer Bar (88). This tightens the
Take-up BeIt (97) on the Take-up Pulley (98) and the
BeIt Pulley (100), and forces the outer surface of the
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Figure 3. Top View 0f NL-z With Escutcheons Removed.
belt against the Motor Pulley (99). Rotation of the
Motor Pulley then drives the Take-up ReeI at fast
forward speed. The brakes are released by the move-
ment of the Slide Plate (47) but the Control BaII Stud
(40A) is moved to the right instead of to the left as
during Rewind operation. When the Rotary Control is
returned to Neutral the brakes are reapplied first to
the Feed ReeI, thus preventing over run and tape
spiIIing.
For the second mode of operation the Rotary
Control (3) is depressed before being rotated. Ro-
tation is then limited to clockwise direction, for play-
backor recording. As the Rotary Control is depressed
the upper stud is disengaged from the Wind and Re-
wind Slide Plate (4?) and a stud on the bottom of the
Control Shaft assembly engages a slot in the PIay and
Record Control Cam (42). As the Rotary Control (3)
turns, the Record Control Cam (42) rotates about a
pivot, acting on three other parts at the same time.
One arm of the Cam (42) moves the control ball stud
to release the brakes and the other arm frees the Slide
Plate Assembly (43) and pushes against the Rocker
Arm (41). The Slide Plate Assembly moves in a
direction to bring the Pressure Roller (22) against
the Capstan to drive the tape. The Rocker Arm pivots
and actuates the Idler Release Lever Assembly (48).
Movement of the Slide Plate Assembly (43) also frees
the Pressure Arm Lever (44) which in turn is moved
by its spring (46) to bring tle Pressure Plate and Pad
Assembly (1a) to bear against the Head assembly (11)
or (12).
Page 6
A third effect of movement of the Slide Plate
Assembly is to free the Takeup Adjusting Lever As-
sembly (61) for rotation. Takeup Pressure Spring (5?)
actuates the Lever (61), forcing Takeup Adjusting Lever
(54) against the Equalizer Bar (88) for correct takeup
tension of Takeup BeIt (97).
When the Rotary Control (3) is returnedto Neutral
a reverse action of all these parts occurs, but the
brakes are applied equally to both reels since neither
is turningat anygreatspeedand danger of tapespilling
is slight.
Volume Control (Model NL-l)
Turning the VOLUME control clockwise in-
creases the volume level for both recording and play-
back.
Volume Control (Models NL-2 & NL-3)
Turning the VOLUME control clockwise in-
creases the volume level for both recording and play-
back. The first few degrees of rotation operate the
amplifier CFF switch.
Tone Control (Model NL-l)
The TONE control varies the relative strength
of the bass and treble frequencies during playback,
but has no effect on the tone while recording. The
first few degrees of rotation operate the OFF switch
which controls both the motor and amplifier.

Figure 4. Top View 0f NL-3 With Escutcheons Removed.
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Tone Control (Models NL-z & NL-3)
The TONE control varies the relative strength
of the bass and treble frequencies during playback,
but has no effect on the tone while recording. The
first few degrees of rotation operate the MOTOR OFF
switch.
Record Lock Button
Depressing the Record Lock Button (33) places
the recording circuits into operation. If the Rotary
Control is then depressed and rotated to the record
position, the Record Lock Button wiII be held in re-
cording position and recording proceeds until the
Rotary Control is returned to neutral This auto-
,matically releases the Record Lock Button.
Automatic I ndex Counter
The Automatic Index Counter (32) provides a
means for locating recorded material anywhere on the
tape. The counter is used on Models NL-z and NL-3.
'Set the counter to zero at the beginning of a reel by
rotating the reset knob. The counter is driven by
means of a Flexible Shaft (103) connected to the Feed
ReeI Spindle (89).
Automatic Shut-Off Switch (Early Versions)
The Automatic Shut-Off Switch is located be-
tween the erase and playback heads on Model NL-3.
When tape is properly threaded it falls between the
contacts of this switch. Thus, when the end of a reel
of tape is reached, or, in the event of tape breakage,
the contacts wiII close.
The switch contacts of relay (M5) are in series
with the motor circuit and are held closed by current
through M5. The Shut-Off Switch is in parallel with
the windings of relay (M5) so that when the Shut-Off
Switch closes at the end of a reel it shorts across the
relay windings and the relay switch opens, breaking
the drive motor circuit.
Automatic Shut-Off Switch (Late Versions)
The Automatic Shut-Off Switch is Iocated to the
Ieft of the play-record and erase head assemirly on
Model NL-3. When tape is properly threaded it falls
between the metal post and the switch arm finger.
Thus,when the end of a reel of tape is reached, or, in
the eventof tape breakage, the metal finger is allowed
to move into the metal post, opening the switch which
breaks the motor circuit.
OPERATI NG I NSTRUCTIONS
Tape Loading And Threading
1. Place a reelof tape on the right hand (supply)
spindle so that the reel wiII turn clockwise when tape
is pulled from the reel. IJse "A" wind tape - that is,
tape that is wound coated side inwards. "B"wind tape
can be easily changed to rrA?r wind by giving the tape
a half twist before threading, and running the tape
through Fast Forward or Rewind operation.
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2. Place anempty reelon theleft hand(take-up)
spindle. Make sure that bothreels areproperlyseated
on the reel rests.
3. Reel out a convenient length of tape and hold
a section straight with both hands. Drop this section
into the tape slot and thread the free end of the tape
into one of the slots in the hub of the take-up reel,
Turn the reel by hand until several turns have secured
the tape to the reel and aII slack has been taken up
between reels.
To Turn 0n Amplifier And Motor
Prepare to record or playback by turning
I'Volume-On-Off" Control to the "on" position. On
Model NL-1 this control also turns on the drive Motor,
but on Models NL-2 and NL-3 the motor switch on the
"Tone" control mustalsobe turnedto the "on" position.
Allow the amplifier to warm up for about 30
seconds before proceeding to record or playback.
To Record From Microphone
1. Insert the microphone plug into the "Mic"
jack.
2. Set therecord level. Thiscan bedone before
tape movement is started by holding down the Record
Lock Button and adjusting the Volume control for pro-
per response from the indicator. The proper volume
levels are as follows:
(a) Model NL-1 (Neon Bulb) -- Adjust the
volume level so that the loudest portions of
the signal cause the Iamp to flash inter-
mittently.
(b) Model NL-2 (Magic Eye) - Adjust the
volume level so that the loudest portions of
the signal just cause the eye to close.
(c) Model NL-3 (VtJ Meter) - Adjust the
volume level so that t}re peaks of meter de-
flection do not go past zero, or into the red
area of dial calibration.
3. Hold the Record Lock Button down and turn
the Rotary Control to the right, thus starting the re-
corder in motion. When through recording, turn the
Rotary Control to neutral. The Record Lock Button
will automatically release and deactivate the record
circuit.
To Record From Radio, TV, 0r Phonograph
1. Connect the output signal from the radio,
tuner, TV, or phonograph to the "Radio" input jack of
the recorder.
2. Proceed as under "To Record From Micro-
phone", step 2.
To Play A Recording
1. Depress Rotary Control and turn it to the
right.
2. Adjust "Volume" and "Tone" controls for
desired Iistening quality.
Dual Track Recording
These recorders are designed so that only one-
half the tape width is recorded at a time, thereby re-
sulting in dual-track recording. To make a dual-track
recording proceed as follows:
1. After a reel of tap.e has been recorded, i.e.
all the tape wound onto the take-up reel, place the
Rotary Control in neutral position.
2. Remove the reels from the recorder, turn
the full reeloverand place itonthe right-handspindle.
Place the empty reel on the left-hand spindle.
3. Thread the tape and proceed with the re-
cording.
4. After the second track has beenrecorded the
f ir st track c an be played, without rewinding, by trading
reels on the spindles as in step 2, rethreading thetape
and placing the recorder in Playback operation.
To Erase Recordings
These recorders automatically erase previous
recordings as new recordings are being made. If it
is desired to erase without recording nevr material,
set all controls as if recording but do not plug in the
microphone or other program source, and run the tape
through the machine. For best results, set Volume
Control at zero.
To Use An External Speaker
Plug the external speaker into the jack marked
"SPKR". On Models NIr2 and NL-3 this automatically
disconnects the internal speakers. On Model NL-l
plugging in an external speaker places it in parallel
with the internal speaker.
To Use An External Amplifier
Connect the recorder jack marked"AMP"to the
input of t}te external amplifier. This input should be
one designed to accept a high level signal requiring no
further equalization for flat playbacl{ response.
To Use As A P.A. System
Anyof the Model NL-1, NIr2, or NL-3 recorders
can be used as a public address system by plugging a
microphone into the RADIO input jack.
MECHAN I CAL ADJ U STMENTS
Equal izer Bar Adjustme nt
This adjustment is made by loosening Socket
Head Screw (2?) and shifting the Equalizer Bar (88)
forwardor backward. Make the adjustment as follows:
Page 8
First, remove the Spindle Caps (1) and ReeI Rests
(2). With the Rotary Control (3) in neutral position,
movetlre Equalizer Bar (88) to a position such that the
Take -Up Spindle (93) is on the verge of spinning without
any pressure being exerted on the Equalizer Bar (88)

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from the Tie Bar (64). After adjustment is made be
sure the socket head screw (27) is tightened securely.
The Equalizer Bar Adjustment Screws (778) are ad-
justed by turning both screws down until they hit the
mechanism plate. Then back the screws off 1/4 turn
and Iock themdownwith Lock Nuts(78El). Thisadjust-
ment acts as a stabilizer for the equalizer bar.
Tie Bar Pressure Adjustment
The amount of pressure exerted on the Equalizer
Bar (88), by means of the Tie Bar (64), is adjustedby
movement of the Elastic Stop Nuts (79). The elastic
stop nuts should be adjusted so as to allow the For-
ward and Rewind positions on the Rotary Control to
function freely and still exert enough pressure on the
equalizer bar for adequate Forward and Rewind per -
formance. To determine if performance is adequate
test the Rewind with a full 7" reel on the feed side.
To test for Wind place the fuII 7" reel on the take-up
side.
NOTE: The Tie Bar (64) must be readjusted wheneve?
the Equalizer Bar (88) is adjusted.
Takeup Adjustment
This adjustment is accomplished by bending the
Take-Up Pressure Spring (54). Bending the spring
closer to the Equalizer Bar (88) increases the pres-
sure on the equalizer bar thus giving a stronger take-
up. Bending the spring away from the equalizer bar
gives a weaker take-up. If bending the spring does not
give adequate results, loosen the screw which mounts
the spring and move the spring in the proper direction
for optimum adjustment.
Brake Adjustment
After equalizerbar adjustments have beenmade
the brakes are ready to be adjusted. First put a full
5" reel of tape on the feed reel side, and an empty 7"
reel on the take-up side. Wind about t/4 of the tape
on to the 7" reel. While operating the Rotary Control
from "Rewind" to "Neutral", tighten the Left Brake
Adjusting Screw (77) until the reels stop in about 1
revolution without spilling tape. Next, reverse thp
procedure by placing the 5" reel of tape on the take-
up side and the empty 7" reel on the feed side. Ad-
just the Right Brake Adjusting Screw (77A) so that the
feels stop in "Fast Forwardfi to Neutral" in about 1
revolution. Next put a full 7" reel of tape on the feed
side and an empty 7" reel on the take-up side. Run
about 100' of tape on to the take-up reel, then go di-
rectly into"Rewind". When the take-up reel isalmost
empty, place the Rotary Control in "Neutral". The
reels should stop in about 3 or 4 revolutions without
spilling tape. Next, reverse the procedure by placing
the full 7" reel on the take-up side and rewind about
100' of tape on the feed reel. Go direcUy into "Fast
Forward" until the feed reel is almost empty. Then
place the Rotary Control in "Neutral". The reels
should stop in about 3 or 4 revolutions without spilling
tape. After the brakes are adjusted, check the take-
up and rewind. If the take-up or rewind has been
affected, readjust. If it is difficult to get adequate
take-up, the brakes mayhave beenadjusted tootightly.
Readjust the brakes to rectify this condition.
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ldler And Speed Change Adjustment
(Models NL-2 & NL-3)
Loosen the set screw and nut which secures the
Speed Change Shaft (69) to Idler Channel (?0). Adjust
the position of idler channel assembly so that the full
perimeter of the ldler Wheel (94) rides on the peri-
meterof the Motor PuIIey(99). The idlerwheelshould
not ride on the edge of the motor pulley. After the
idler channel has been positioned correctly in a ver-
tical direction on the speed change shaft, check to see
that the shaft has not rotated so that the speed change
sector no Ionger engages the slot in the Speed Shi-ft
Lever (26). If necessary loosenthe Speed Change Shaft
Knob (24) and reposition the Speed Change Sector (25).
Play-Record Head Alignment
The PIay-Record Head is correctly aligned for
azimuth when the magnetic gap is at an exact right
angle with the direction of tape travel. One of the best
ways for making an azimuth adjustment is by means
of analignment tape and a meter. A substitutemethod
would be to play back a recording and adjust the head
for maximum high frequency content in the output, as
judged by ear. The use of alignment tape and meter
is as follows:
1. Connect the meter to the "AMP" output jack
and set it for a low AC voltage range.
2. Loosen the record head mounting screw just
the slightest amount, so that the head may pivot about
this screw as a center, but cannot slip up or down
vertically.
3. PIay the alignment tape and adjust the Azmur-
X spring loaded screw for maximum output on the
meter.4. Check to see that the height of the head has
not been disturbed. The center line of the head and
pole piece must be lined up so that the pole piece is
at the same level as the tape guides and tape.
5. Tighten the head mounting screw and seal
the Axmur-X adjustment screw with a small amount
of household cement.
Record Level lndicator Adjustment (Model NL-I)
The neon lamp on your tape recorder indicates
the maximum undistorted recording level, and although
set at the factory, it may require a minor adjustment.
When this becomes necessary,the following ad-
justment procedure is suggested.
1. Allow the recorder to thoroughly warm up.
(usually about 5 minutes).
2. Insert a thin screwdriverthrough the "AMP"
jack hole.
3. Set the volume control at approximately 2
o'clock and makea normal recordingholding the mic-
rophone 4" to 6r' from the mouth. Speak into the mic-
rophone at a normal conversational level.
4. Slowly turn the screwdriver until the neon
bulb just flickers at the peak or loud portions of your
voice,
To check the above setting, playback the record-
ing to see that the level of playback is entirely ade-
quate and not distorted at normal listening levels.
If playback is weak, repeat step 4 but slightly
increase the volume control.
If playback is loud and distorted, repeat step 4
but slightly decrease the volume control.
Depending on the individual's voice the above
procedure may have to be repeated several times be-
fore the desired recording level is obtained.
PARTS REPLACEMENT
How To Replace A Pole Piece
Remove the head assembly by loosening the
mounting screws which hold down the assembly. The
pole piece is then removed by inserting a non-magnetic
screw driver between the head can and the pole piece
and prying the pole piece by breaking the glue joint.
The new pole piece is then inserted between the two
laminations provided for each leg of the pole piece.
After the pole piece is in position it should be cement-
ed from the sides with household cement. The head
assembly is then screwed into place and the heads
aligned.
How To Replace A Play-Record Head
Remove the #6-32 Phillips OvaI Head Mounting
screw (6) and the Head Cover Casting (5). This wiII
give access to the heads. Unsolder the head leads at
the head plug socket or at the terminal lugs. Loosen
the Azmur-X adjustment screw and the head mounting
screw (see Fig. 6). The head can now be replaced.
Page l0
AZMUF -X
The head should be aligned for correct aximuth after
replacement.
Figure 6. Head Adjustment Points.
How To Replace A Pressure Roller
Remove the #6-32 Phillips Oval Head Mounting
Screw (6) and the Head Cover Casting (5). Remove the

Figure 7. Bottom View 0f NL-l Mechanism.
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Page ll

Figure 9. Bottom View 0f NL-z & NL-3 Mechanism.
Figure I0. Bottom View 0f NL-z & NL-3 With Motor Mtg. Plate Removed.
Page 12

crescent retaining ring (21) and lift off the pressure
roller. Clean the pressure roller stud andclock steel
washer (23) with a dry cloth. Apply grease to the in-
side bottom of the new pressure roller. Put the new
pressure roller on the pressure roller stud and wipe
off anyexcess grease at the topof the roller. Replace
the crescent retaining ring, Do not get any grease on
the driving surface of the pressure roller as tlis wiII
hinder the operation of the machine.
How To Replace An ldler Wheel
Remove the Motor Support Plate (10?) by taking
out the4 #10-32 machine screws (108). This will give
access to the Idler Wheel. Slide the Idler Spring CIip
(92) forward and slip it off the shaft, then remove the
clock steel washer and the Idler wheel from the Idler
stud. Clean the stud before installing a new ldler. In-
stall idler wheel in reverse order, being careful not
to get any grease on driving surface of wheel. Replace
Motor Support plate.
How To Replace An Equalizer Bar
On Model TM-1 first remove the back plate con-
taining output jacks and slide switch. Remove the
Spindle Caps (1), ReeI Rests (2) and llead Cover Cast-
ing (5). Loosen the set screws on feed and take-up
puUeys, (Remove flexible shaft on feed reel spindle,
Models NL-2 & NL-3). LiJt out both reel spindles
from top of unit and remove the elastic stop nut (79)
and spacer (80) from the end of the Tie Bar (64). Re-
move socket head screw (2?), Equalizer Pivot Stud(90),
and Equalizer Spacer (8?). Equalizer bar can then be
removed and replaced. Clean aII bearing surfaces and
washers and lubricate properly before replacementof
bar. After new baris installed follow instructions for
Equalizer Bar, Tie Bar, and Brake Adjustments.
How To Replace A Motor Assembly
Place Rotary Control (3) in Neutral position.
Remove the 3 nuts (?3) and washers which hold the
Motor Plate to the rubber shock mounts. Li.ft motor
off the three mounting studs. When replacing motor
make sure that motor pulley (99) is outside the take
up belt (9?) as shown in the exploded view.
How To Replace A Take-Up Belt
The removal and replacement can probably be
most easily accomplished if the back of the unit is
facing up. SIip the belt off the take-up pulley (98)
first. Start t}te belt up over the edge of pulley and
assist the action by turning take up reel seat by hand.
Then remove the belt from the BeIt Pulley (100) by
slipping the beltup through the clearance in the Motor
Support Plate (10?). Replacement is done in the re-
verse order. Make sure that the lettering is on the in-
side of belt thenslip the beltover [tre Belt PuIIey (100)
by working it up through the clearance in the Motor
Support Plate. PulI the belt around under the Motor
Pulley (99) and work it up between the Motor Pulley
and the motor mounting stud, towards the Take Up
Pulley (98). SIip the belt over the Take Up Pulley.
The Equalizer Bar and Tie Bar may require readjust-
ment after the new belt is installed.
How To Replace A Feed Belt
Turn the unit upside down and remove the head
leads and the flexible shaft. On Models NL-1, NL-2,
and NL-3 the head leads can be unplugged but on the
basic TM-l mechanism they will need to be unsolder-
ed. The flexible shaft is used on Models NL-2 and
NL-3. The belt can now be removed from the feed
pulley but the Motor Support Plate (10?) must be re-
moved before the belt can be taken off the Flywheel
and Capstan Assembly (76). Remove the four #L0-gz
screws (108) and remove the Motor Support Plate. The
Feed Beltcan now be completelyremoved and replac-
ed. Make sure that new belt is installedwith lettering
on the outside. Reassemble in reverse order, making
sure that Motor Support Plate is properly seated on
the studs.
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Although this mechanism is prelubricated at the
factory, replacement of parts requires that they be
lubricated in order to insure proper functioning. No
part needs more than a slight film of grease where
grease is specified or one drop of oil where oil is
specified.
The following parts require greasing with fibre
grease or a similar compound:
1. Play-record cam (42).
2. Wind-rewind slide plate (4?).
3. Control spring (65).
4. Control BalI shaft (40A), bottom end.
5. Slide plate assembly (a?).
6. Pressure roller bearing, (22) and (3?).
?. Belt pulley (100).
8. Tie bar (64), front end.
9. Idler wheel bearinC (94).
10. Record lock (33).
11. Equalizer bar pivot stud (90|.
12. Take-up adjusting lever (61).
13. Pressure arm lever (44).
14. Pressure finger carrier assembly (3?).
The following parts require oiling with 10W
lubricating oil:
1. Feed spindle assembly (89).
2. Take-up spindle assembly (93).
3. Flywheel assembly (?6).
CAUTION: Do not clean oilite bearings with cleaning
solvent. Oilite bearings are permanently
oiled, but in some cases where the bear-
ings appear dry a drop of oil will be nec-
essary.
LUBRICATION
CLEAN I NG
The recording and erase heads, the capstan
(?6), and the pressure roller (22) are subject to an
accumulation of tape coating oxide which'is worn off
the tape as it passes these parts. Clean these parts
with a soft cloth and alcohol after every ten hours of
running time.
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Page 13

HEAD ASSEMBLY FOR
MODELS Ttvtl, NL-I, & NL:
COUNTER FOR MODELS NL.z AND NL-3
A PHOTOFACT "EXPLODED" VIE\Y
@ Howard W, Sams & Co,lnc. 1958
Page 14
Figure 1IA. Exploded View 0f Parts Above Mechanism Plate

FASCO OR
UNIVERSAL MOTORALLIANCE OR GENERAL
INDUSTRIES MOTOR
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Figure llB. Exploded View 0f Parts Below Mechanism Plate

MECHANICAL TROUBLES AND PROBABLE REMED IES
SYMPTOM CAUSE REMEDY
No rewind. l.Glazed idler wheel (94). 1.Rub off glaze with a clean, dry, lint free cloth.
2.Faulty tie bar (64) adjustment. 2.Adjust as described under "Tie Bar pressure Ad-
justment".
3.Idler wheel (94) slips against 3.Clean idler wheel, flywheel, and motor pulley with
flywheel or motor pulley. alcohol. If idler wheel still slips, replace.
4.Idler wheel (94) not adjusted 4.Adjust as described under "Idler And Speed Change
properly. Adjustment".
S.Binding feed reel spindle (89). S.Remove "E" ring (8b) and remove spindle from
bearing. Clean bearing and spindle with a clean,
soft cloth.
6.Draggingbrakelinings. Brakes 6.Adjust brakes as described under "Brake Adjust-
not adjusted properly. ment".
?.Warped reel rest (2). T.Replace reel rest.
8.Feed belt (101) loose or broken. S.Replace.
FLutter. l.Motorpulley (99) not concentric l.Replace motor and pulley assembly.
to motor shaft.
2.Excessive take-up. 2.Adjust as described under "Take-up Adjustment".
3.Take-up belt (97) not installed 3.Remove and replace belt as shown on "Exploded
Properly. View".
4.Dirty flywheel bearings. 4.Clean bearings and flywheel shaft with a clean, soft
cloth.
Wow. l.Foreign matter on idler wheel l.Clean with a cloth and alcohol.
(94), motor pulley (99), flywheel
(76), or take-up pulfey (98),
2.Defective idler wheel (94). 2.Replace.
3.Defective pressure roller (22). 3.Replace.
4.Reel spindles (89) and(93) bind- 4.Remove "E"ring (85) on top of spindles and remove
ing. spindlesfrom bearings. Clean bearingsandspindles
with a clean, soft cloth.
S.Brakes improperly adjusted. S.Adjust as described under "Brake Adjustment",
No Wind (Fast For- l.Binding take-up spindle (93). l.Remove "E" ring (85) ontop of spindle and remove
ward). spindle from bearing. Clean bearing and spindle
with a soft, clean cloth.
2.Takeup belt (97) loose, twisted, 2 .Replace belt.
or broken.
Tape spillage or in- l.Faulty brake adjustment. l.Adjust brakes as described under "Brake Adjust-
sufflcient braking. ment".
2.Worn brake linings. 2.Replace linings and readjust brakes.
3,Wornoutorloosecontrolspring 3.Adjust or replace control spring.
(65).
4.Excessiveplay inequalizer bar 4.Readjust equalizer bar as described under "Equal-
(88). izer Bar Adjustments".
Page 16

ELECTR ICAL TROUBLES AND PROBABLE REMED IES
SYMPTOM CAUSE REMEDY
Poor high frequency
response. 1.Play-Record head improperly l.See "PIay-Record Head Alignment".
aligned
2.Wornpolepieceon PIay-Record 2.Replace pole piece and realign for azimuth.
head.
No erase -- distorted
or weak record. 1.Bias-Erase oscillator not work-
ing. l.Check oscillator tube and oscillator coil. Replace
if necessary.
No erase - records
on top of previous
recording.
l.Defective erase head or cir- l.Check circuits - replace head if necessary.
cuits.
Distorted recording
- play-back function
o.K.
l.Improper recording level.
2.Defective microphone.
l.Check operation of level indicator. Check setting of
adjustment for level indicator (Model NL-1).
2.Compare with microphone known to be good.
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Page 17

6V6GT 6X5GT 65L7GT 6J7
Figu re L2. Rear View 0f NL-l Amplifier.
Page 18
Figure 13. Front View 0f NL-l Amplifier.

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Figure 14. Schematic Diagram 0f Model NL-I.

6V6GT 6X5GT 65L7GT 6J7
Figure 15. Rear View 0f NL-Z Amplifier.
Page 20
Figure 16. Front View 0f NL-2 Amplifier.
This manual suits for next models
5