The Pentron tape recorder is an instrument for making high fidelity recordings of music or speech on magnetic tape. Realistic reproduction of the recordings is provided by a self-contained, high power amplifier and speaker.

A brief description of the operating components fol lows. It is recommended that the prospective operator use this to familiarize himself with their operation before attempting to use the instrument,

TAPE The Pentron recorder uses 14 " wide Magnetic Recording Tape with Type A winding. Type A winding simply means that the magnetic coating or dull side of the tape is wound facing in. Type B tape (dull side facing out) can be changed to Type A for use on this machine by merely rewinding with a half twist,

Either plastic or paper recording tape can be used. For best results, use a red oxide tape, preferably plastic. Since the Pentron recorder is very easy on tape, it is quite practical to use the higher priced plastic tape. Recordings can be played back and tape re-used many thousands of times without noticeable change in performance.

For use on this machine tape may be wound on either the popular 7 " reel (1200 feet) or any smaller size reel.

Tape can be spliced by bringing the ends together (not lapped) and applying a small piece of transparent scotch tape to the shiny side on plastic tape or to the grey side on paper tape.

Always keep tape clean and store preferably in humidor cans, much the same as you would movie film.

CAPSTANS - There are two Capstans which control the speed of the recorder. The small Capstan which carries the tape past the heads at a speed of 39/4 " per second, (one hour playing time in one direction on a 1200'reel), or the larger Capstan which moves the tape at 7/2 " per second, (one-half hour playing time in one direction on a 1200'reel). The smaller Capstan permanently built into the machine and should not be removed unless service is required. The larger Capstan is a sleeve which can be slipped over the smaller Capstan and tightened effectively by turning its knurled head a few turns in a clockwise direction, MASTER CONTROL KNOB MUST BE IN " IDLE " POSITION, MACHINE MUST BE TURNED OFF, AND MOTOR RELEASE PIN MUST BE IN THE " IN " POSITION SO THAT CAPSTAN CANNOT BE PUT ON TOO TIGHTLY. Otherwise difficulty will be experienced in re moving the Capstan. To remove the large Capstan, the motor must be turned OFF, the motor release pin in the OUT position, and with the Master Control Knob in the IDLE position, proceed to unscrew the Capstan. The initial loosening can be accomplished by grasping the knurled portion of the Capstan and giving it a quick twist in a-counter-clockwise direction. If capstan is difficult to re move, grasp right hand reel spindle and push firmly toward rear of case at same time turning capstan counter-clockwise.

The smaller or slow speed Capstan is used for. economic long period playing. The reproducing qualities. are about the same as that of a very good AM radio broadcast.

The larger or high speed Capstan is recommended where best high fidelity is required particularly on exceptionally fine music, the reproducing qualities being equivalent to that of a very fine FM radio broadcast.

A recording made at high speed must be played back of high speed and similarly, a recording made at slow speed must be played back at slow speed.

DUAL TRACKS TWO CHANNEL After a reel of tape has been recorded, the reel with the tape will be on the left hand spindle. To record on the second channel, turn the reel over and place it on the right hand spindle. It will then be in position for recording or playing back on the second track, On completion of the second track, you are then ready to repeat playing of the first track without rewinding. Switching of the reels selects the right track.

POWER SUPPLY This unit operates only on 110 Volt, 60 Cycle, AC current. Use of any other supply directly into the unit will result in serious damage to the Amplifier section.

MECHANICAL INTERLOCK - An automatic mechanical interlock, not visible from outside, makes it impossible to actuate one control knob while the other is being used. Therefore, do not attempt to force the knobs.

TONE CONTROL The Tone Control also contains the master switch which turns the amplifier and mechanism OFF and ON. The click of this switch can be heard when this Control Knob is turned to the extreme counter clockwise position.

The Tone Control decreases the high frequency response when turned clockwise. It is automatically disconnected during recording. Therefore, when recording from a radio be sure the tone control on the radio is set for maximum treble. These highs may be subdued with the Tone Control on Recorder during playback.

VOLUME CONTROL This controls the volume for both playing and recording. For recording, the Volume Control should be set according to the reactions on the Volume Indicator Eye.

EXTERNAL AMPLIFIER JACK To use your tape recorder with an external amplifier simply connect the external amplifier to the proper jack. The VOLUME and TONE controls on the recorder should be turned completely clockwise; the recorder will then operate through the external amplifier. Use the volume and tone controls on the external amplifier for proper adjustment.

EXTERNAL SPEAKER JACK When an external speaker (3.2 voice coil) is connected to your recorder the internal speaker is automatically disconnected and the entire out put will be heard through the external source. For privacy of playback a set of low impedance earphones can be

Plugged into this jack,

RADIO JACK - For recording or enjoying any radio program, plug your radio tuner in the Radio Jack, using other controls in the conventional manner for recording or listening. The radio jack will also take the output of any external high fidelity, high impedance pick up.

MOTOR RELEASE PIN When this pin is pulled to the OUT position, the motor is engaged with the flywheel. When it is in the IN position the motor and flywheel are disengaged.

Always leave the Pin in the IN position when the machine is not in use. This prevents bumps or dents in the rubber surface of the flywheel which result in rough operation.

OPERATION

MASTER CONTROL KNOB When this knob is turned to the PLAY position, the machine will reproduce the program recorded on the tape.

FIGURE - 1

When turned to the RECORD position, the machine vill record whatever material that is desired. This position cannot be gone into without first pressing the RED

Lock Button. This is a safety feature which prevents accidental erasure of the recorded program. When turned to the IDLE position the tape will stand still, unless it is desired to rewind or skip. REWIND AND SKIP KNOB With the Master Control Knob in the IDLE position, turning this knob toward the REWIND position will cause the tape to rewind on the Feed Reel at any desired speed up to a top speed of 187 inches per second. Similarly, by reversing the knob and turning it toward the SKIP position you can reach the desired spot within a matter of seconds.
Switching the direction of this control knob will act as a very effective brake in cutting down the speed of the reels and it is recommended that this method be used where fast stopping is necessary. However, it is better for the mechanism if this fast-braking is used moderately.

NEVER GO FROM FAST REWIND INTO PLAY OR RECORD WITHOUT FIRST BRINGING THE REELS TO A STOP. FAILURE TO COMPLY WITH THIS MAY RESULT IN UNROLLED AND POSSIBLY TORN TAPE. LOCK BUTTON When this button is pushed, the ma chine is switched from a reproducer to a recorder. It thus erases whatever passes in front of the Erase Head whether the machine is playing, rewinding or recording. It must be depressed manually and it will stay down when the Master Control Knob is turned to RECORD. This makes it possible to make new recordings on tape which already has undesirable recordings on it and it con be held down manually when the Master Control Knob is in the PLAY position. This makes it a most desirable feature for spot erasing or dubbing in on pre-recorded tape. This can be done so rapidly that words can be erased and new ones added with split second accuracy.

VOLUME INDICATOR EYE This is intended for use during recording. Ideal recording volume level is attained when the loudest portions of the signal just cause the eye to close. If too high a level is used, distortion will occur; too low a level will result in relatively higher background noises.

THREADING Refer to Figure 1. Place an empty reel on the Take Up Reel Spindle (left hand spindle).

Place a reel of tape on the Feed Reel Spindle (right hand spindle) so that it unwinds clockwise. Be sure that both reels are engaged with the drive pins on the spindles. Bring the end of the tape over to the Take Up Reel and take up several turns of tape. A pencil or similar object is useful in holding the tape against the hub while making these preliminary turns. Now pick up the loop of tape between the reels and drop it into the slot in front

Of the Recording Head and between the Capstan and Pressure Roller. Make sure the tape is all the way down in the slot.

REPRODUCING OR PLAYING BACK RECORDED TAPE - Place reel of tape on machine. Plug into 110 Volts, 60 Cycle, AC receptacle and turn Tone Control Knob clockwise to switch ON position. Allow a few moments for the Amplifier to warm up as you would on a radio set, Now turn the Master Control Knob to PLAY and adjust the Volume and Tone Controls to suit. Do not press the RED Lock Button unless you wish to erase.

RECORDING - Using Microphone Plug Microphone into the Mic. Jack. Set up the rest of the machine as you would for PLAY but do not turn the Master Control Knob as yet. It is generally advisable to set the volume level before starting the recording. To do this, hold down the lock Button and adjust the volume control while a sample program is going on. (The tape is standing still.) Now you are ready to record. Start recording by turning the Master Control Knob to RECORD. The position of the microphone is important. For recording voice, the distance from the source to the microphone should be kept as small as possible for best results. In recording music, greater distances are desirable because the room acoustics usually improve the music.

SERVICE

GENERAL The Pentron tape recorder was engineered and developed to give excellent performance over a long period of time. It is, of course, expected that there will be occasional tube failures as with radio and television but this will be at a minimum.

The machine should be kept clean and any accumulation of dust from the tapes should be blown or brushed away from the Heads or around the Capstan. The faces for the Pole Pieces in the Heads can be cleaned by. wiping them with a cloth dampened with Carbon Tetra chloride.

LUBRICATION - This machine is equipped with special ail impregnated bearings on all wearing surfaces and will never need lubrication during its entire lifetime.

ADJUSTMENTS - To take unit from case, remove 4 screws from the bottom side and lift unit out.

Ali adjustments on this unit are of a permanent nature and have been set precisely at the factory, therefore, they should need no further setting. If the unit requires

Readjustment, the following procedure will put the unit in operating condition. This outline covers a complete re adjustment of all parts and all may not be required in every case. In the event that only individual adjustments are required, these can be made by following the applicable instructions.

FIGURE - 2 THESE PARTS ARE LOCATED BEHIND MOTOR AT REAR OF UNIT

ADJUSTING MOTOR DRIVE - The motor drive is ad. justed by the turning of screw B'(Fig. 2). The correct amount of engagement is determined by stopping the large capstan with the finger while it is running in the play position. When this becomes rather difficult to do, there is sufficient engagement to insure proper operation. Loosening screw B increases engagement; tightening screw 8 decreases engagement.

Do not adjust screw B beyond proper engagement as this will place unnecessary and excessive load on the motor which might result in distortion and wows. After adjustment has been made with screw B, lock in place with nut C.
Nut A has been adjusted in the factory and ordinarily need not be touched. If for any reason, sufficient engagement cannot be obtained by adjusting screw B, turn Nut A several revolutions clockwise. Before replacing unit in the case, loosen the large capstan. To do so, it may be necessary to hold the flywheel located at the lower end of the capstan shaft.

TRACTION OR " DRAG " ON REEL SPINDLES Loosen Screw D (Figure 1) to move Equalizer Bar forward or backward. With Control Knob in IDLE position and with an equal amount of tape on each reel move the Equalizer Bar back until a slight amount of drag is noticeable on each reel spindle. Check by drawing a small loop of tape from each reel. These loops should stay immobile. If the reels take up the slack at this point, the amount of drag is too great and should be relieved very slightly.

Should the tape have a tendency to wind up or creep onto the Take - Up Reel while making the above adjustment, correction can be made by maneuvering the Nuts EE and FF (Figure 3) backwards on the Tie Bar. These parts are located on the underside of the Top Mechanism Plate and below the Feed Reel.

FIGURE - 3

TAKE UP ON TAKE UP REEL - Take up adjustment on the Take Up Reel is required if when the Control Knob. is placed in the PLAY or RECORD position, a loop of tape feeds out before the Take Up Reel starts turning, or if the Tape Pressure Fingers in front of the Heads are not engaged with the tape before the Take Up Reel starts turning.
This adjustment is accomplished by loosening screw G (Figure 1) and moving bar H towards the Equalizer bar for decreasing the time required for the Take Up Reel to start turning and, of course bar H must be moved away from Equalizer Bar to increase the time.

TAPE PRESSURE FINGER ADJUSTMENT For most satisfactory results the tape should lay across the full face of the Pole Pieces. Too little coverage of the Pole. Piece face will result in indistinct recordings and reproductions. Too much pressure will be accompanied by increased drag and unnecessary wear on the tape. The Tape Pressure Fingers are properly adjusted when the tape is depressed approximately 1/16 " from the front face of the Pole Piece. This is accomplished by loosening Screw L (Figure 1) and moving Post M to the desired location.

HINTS

MONITORING - When recording from an external source, (such as FM or AM tuners, phono pickup) the program may be heard by plugging earphones into the amplifier jack.

FLAT SPOT - Flats moy develop on the flywheel if the motor release pin is not pushed in (according to direction) while machine is not in use. To remedy this condition, set the machine in play position and let run until flats are removed.

PARTS LIST

SCHEMATIC TAPE RECORDER