Matsushita Electric NATIONAL RQ-152S User manual

NATIONAL
TAPE RECORDER
SERVICE MANUAL
aT Sica Say
NEY
MODEL RQ-152S
A.C D.C 2 SOURCE TAPE RECORDER
CONTENTS
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MATSUSHITA
ELECTRIC
JAPAN

SPECIFICATIONS
Power Source:
Audio Output:
Transistors :
Recording System:
Erasure System:
Track System:
Monitor Systen:
Tape Speeds:
Frequency Response:
Input Impedance:
Output Impedance:
Playing Time:
Battery Life:
Recording Level Indicator:
Built-in Speaker:
Dimensions:
Weight:
PARTS LOCATION
Supply Reel
Operating Lever
Counter Reset Button
Index Counter
V.U Meter
Record Button
Fast Forward Button
Volume Control Knob
Tone Control and Monitor Switch Knob
A.C. or Battery Powered A.C. 110V, 220V
Battery 9V 6 Batteries
700 mW (1W maximum)
2SB-173(1) 2SB-175(2) 2SB-178(2) 2SB-172(1)
AC. Bias 35K Cycles
D.C. Erase
2 Track System
Sound Monitor System
3-3/4i.p.s. and 1-7/8i.ps.
100~7,000 c/s at 3-3/4 i.p.s.
100~4,000 c/s at 1-7/8i.ps.
Microphone 20 KQ
Auxiliary “RADIO” 100 KO
Extension Speaker Jack “EXT.SP” 8 Q
1 hour at 3-3/4i.p.s. with 5” Tape (600 ft)
2 hour at 1-7/8i.p.s. with 5” Tape (600 ft)
More than 30 hours (using NATIONAL “Hi-Top” Batteries)
V.U Meter
3-5/8” Dynamic Speaker
11-3/4’ (W) x 10” (D) x 3-1/2” (H)
6-3/4 Ibs. without Butteries
Takeup Reel
Capstan Rest
Capstan
external Speaker Output Jack
Radio Jack
Microphone & Remote Control Jack

BLOCK DIAGRAM OF ELECTRICAL CIRCUITS
RECORDING CIRCUIT
MONITOR
Ue Sound
Monitor SW. SPEAKER
Feedback
Deen ” Record
y, J
MIC. Head
Tr Tr2
2SB-173 2SB-175
Transformer
Transformer
2SB-178
“B” Transistor
Tré
258-172 Power Source
Erase
A.C Power Source
Motor
PLAYBACK CIRCUIT
Negative
Feedback
Tr4
Equalization
Tone
Control
MONITOR
©
SPEAKER
Volume
Playback Control
Head
Tri Tr2
2SB-173 2SB-175 2SB-175
* Input Out put
Transformer Tr5 Transformer
2SB-178
A.C
Power
Source
“B”"
Transistor
Power
Source
Ln ee ee)

DISASSEMBLY
INSTRUCTIONS
1.
Remove
the
operating
Lever
and
the
capstan
sleeve
3-3/4 ips.
2.
Remove the
Bottom
Cover.
BOTTOM COVER 3. Undo chassis fixing screws 6 pcs. (C).
AC Power Cord 4. Hold the Flywheel of chassis, and pull it up slopewise
Battery Compartment Cover Compurtment Cover from Reel Table side.
Note: Attention must be paid to lead wire from
IN 4 speaker.
= —
MOTOR
1. Turn the set upside down.
2. Undo the fixing screws 3 pcs. (A) of the Bottom Cover
and the fixing screws 2 pcs. (B) inside of the Battery
Case. Position of al
3. If it is lifted from the hinge side, the Bottom Cover id (e STONE Mark [8 |
can be removed.
Note: Attention must be paid to lead wire from
Battery.
MAIN CABINET BODY CASE
Head
Cover
Oe
ak
Sleeve
3-34
i.p.s.
. Remove the Motor Spring from the Motor.
. Remove the 3 Motor Lead wires (Yellow, Red and Blue.)
. Remove 2 screws (D) holding Motor Holder.
. In doing so mark the original position of the Holder
first.
When replacing the Motor, fit it to the position marked
When removing the old Motor, then test the tape
Operating
Lever
speed.
COUNTER
PWRHYr

FLYWHEEL
(>) Paper Washer
1. Remove Paper Washer
and Stop Ring on the
Flywheel Shaft (Capstan).
Takeup Reel Table
Takeup Belt
Guide Pulley-A
2.
Remove
the
Rubber
Belt
from
the
Guide
Pulley-A.
(E) Sub Base Plate
>) Ss
| wee
; Ss QE 2] ry
EF
Clutch Lever Spring Catch Lever Spring
3. Remove the Catch Lever Spring and the Clutch Lever
Spring.
4. Remove the 3 screws (E) holding the Sub Base Plate.
5. Remove the Sub Base Plate.
6. Pull the Flywheel upward.
When replacing the Flywheel, always install new
Flywheel.
Thrust Ball and Paper Washers on the Flywheel Shaft
i RA Paper Washer
(a
[ie ea22 5~
Flywheel Thrust Ball
MECHANICAL OPERATING
CONTROLS
SINGLE LEVER CONTROL
All electrical and mechanical functions are performed by
the single, 4 position Operating Lever. The batteries are
disconnected in the STOP position.
1. Turning the Operating Lever counter-clockwise to the
PLAYBACK position switches the Amplifier ON and
actuates the tape transport mechanism to properly
Playback a recorded tape.
2. Turning the Operating Lever counter-clockwise to the
REWIND position switches the Amplifier OFF and
actuates the mechanism to cause transport of the tape
onto the supply reel.
3. Pressing the Record/Lock Button and tuming the
Operating Lever to RECORD actuates the tapetransport
mechanism and switches the electrical citcuits, to
enable the signal from the microphone to be recorded.
Record/Lock Button is a safety locking device to
prevent accidental erasure.
4. Volume Control is used to adjust the recording level
and volume of the reproduced sound. It is not connected
to the Power Switch.
5. V.U Meter/Battery Voltmeter functions a; a dual
purpose meter. With the Operating Lever in the RECORD
position, the meter functions as a V.U Mter and
indicates the recording level. In the PLAYBACK position,
the meter functions as a Voltmeter and measures the
Voltage output of the batteries.
6. The Model RQ-152S is equipped with a self-omtained
AC power supply and a unique relay circit which
allows automatic switching from AC to Battery power
and vica-versa.
S4 is the AC to Battery switch contacts and normally
is in the Battery position. When AC power i; applied,
S4 contacts are switched to the AC positio, by the
Relay.

TAPE TRANSPORT OPERATION
PLAYBACK
up Reel Tabke
Takeup
Reel
Table
Guide
Pulley
(Guide Puiley:$))
Clutch Lever
(Gam Plate)
Clutch Lever
Supply Reel Table
(Beit Retarn Stopper Lever)
~ An? 2
een i FF Roller Lever)
Rubber of Belt Return) / [af 4
Stopper Lever
(N9
Rewind Pulley
Sub F.F.Lever
When the operator is adjusted to playback condition by
turning the Operating Lever, the following movements
occur at one time to feed tape at a constant speed for
obtaining playback.
1. Clutch Lever acts, power source is switched on, Motor
Lifter is freed from suppression, Motor is pressed on
Flywheel, and motor rotation is transmitted to Flywheel.
2. Rotation transmitted to Flywheel turns Takeup Reel
Table by Takeup Belt and Sub Takeup Belt.
3. Pinch Roller Lever acts and makes Pinch Roller stuck
to Capstan Shaft. With rotation of Capastan Shaft
which is conjointly shaft of Flywheel, Pinch Roiler is
rotated to feed tape at a constant speed.
4 Pinch Roller Lever moves pad arm and Pinch pad
to Head.
5. Pinch Roller Lever moves Sub F.F. Lever and F.F. Roller
Lever, and separates F.F. Roller from Takeup Reel
Teble.
6. Rewind Lever is actuated, Rewind Pulley is separated
from Flywheel, and playback circuit is switched on.
7. Sub Clutch Lever operates, moves Belt Return Stopper
Lever and separates rubber of Belt Return Stopper
Lever from Supply Reel Teble.
8. Catch Lever operates and fixes operator.
RECORD
Recording Lever
Recording Cam
Push the Button for recording, turn the Operating Lever,
and adjust the operator to recording position. Then, same
operations as in playback begin simultaneously and tape
is fed at a constant speed. At the same time, Recording
Lever is moved with Recording Cam, Slide Switch is
actuated, electric circuit is changed over to recording
condition, and thus recording is obtained.
FAST FORWARD
(F-F.Roller)
|
Guide Pulley L)
{
F.F.Roller Lever}
Takeup Reel Table
Friction Pulley:
AF. Pulley
(Fivwheel)
-~ (Pinch Rolier
Lever
Pa
oD
(FF Lever) -
Cam Plate)

Takeup Reel Table
F.F.Roller
Sub Takeup Belt
Friction Pulley
Push the F.F. Button, turn the operating Lever, and
adjust the operator to Fast Forward condition. Then
the following operations begin simultaneously for F.F.
of tape.
1. Clutch Lever operates, power source is switched on,
Motor Lifter is freed from suppression, Motor is pressed
on Flywheel and motor rotation is transmitted to
Flywheel.
2. Rotation transmitted to Flywheel turns Friction Pulley
under Takeup Reel Table by Belt, the rotation is
transmitted to F.F. Roller and its rotation to F.F. Pulley.
As F.F. Pulley is fixed at Takeup Reel Table, the Reel
Table quickly rotates.
3. Sub Clutch Lever operates, moves Beit Return Stopper
Lever, and separates Rubber of Belt Return Stopper
Lever from Supply Reel Table.
4. Catch Lever works and fixes operator.
REWIND
Supply Reel Table
Rubber
of
Belt
Return
Stopper
Takeup Reel Table
Flywheel
(Takeup Lever)
Turn the Operating Lever for putting the operator to
rewinding condition. Then the following operations
simultaneously occur, and the tape is quickly rewound.
1. Catch Lever operates, power source is switched on,
Motor Lifter is freed from suppression, Motor is pressed
on Flywheel, and Motor rotation is transmitted to
Flywheel.
NO
. Rotation transmitted to Flywheel is further transmitted
to Rewind Pulley which is pressed on Flywheel, and
Supply Reel Table is turned to rewinding direction by
Rewind Belt.
3. Takeup Lever operates, separates Sub Takeup Lever,
F.F. Roller Lever and push F.F. Roller from Takeup Reel
Teble, putting the Takeup Reel Table in freed condition.
4. Sub Clutch Lever operates, moves Belt Return Stopper
Lever, and separates Rubber of Belt Return Stopper
from Supply Reel Teble.
5. Catch Lever operates and fixes operator.

STOP
(FF Roller)
‘Supply Reet Table
(Takeup Reel Table)
_- (Sub_Takeup Beit)
Sub Clutch
Lever E
Pinch Roller eo Se) AAAY
__ Spring /
a
(Catch Lever Spring) (FF Lever)
| S€ Fleer
(Clutch Lever
From the status of Record/Playback, quick feed or Rewind-
ing, if the Operating Lever is turned and the operator
is adjusted to stopping condition, the following movements
occur simultaneously, power source is switched off, and
operation come to a stop.
1. Clutch Lever works, power source is switched off, Motor
Lifter is suppressed, and Motor is separated from Fly-
wheel.
2. In case of stopping from Record/Playback, Rewind
Lever works, circuit for Record/Playback is cut off,
and Rewind Pulley is pressed on Flywheel.
Pinch Roller Lever works, Pinch Roller is separated
from Capstan Shaft, and the Pinch Roller Lever also
actuate pad-up for separating pad from bed.
By operation of Pinch Roller Lever, Sub F.F. Lever
and F.F. Roller Lever are actuated to press F.F. Roller
on Takeup Reel Teble which serves as a_ brake.
Sub Clutch Lever and Belt Return Stopper Lever work
to press Rubber of Belt Return Stopper of Supply Reel
Table for braking.
3. In case of stopping from Fast Forward, Rewind Lever
works, and Rewind Pulley is pressed on Flywheel. Sub
Clutch Lever and Belt Return Stopper Lever work to
press Rubber of Belt Return Stopper on Supply Reel
Table for braking.
4. In case of stopping from rewinding, Takeup Lever and
Sub Takeup Lever work to press F.F. Roller on Pulley
of Takeup Reel Table.
Braking is effected when F.F. Roller comes in touch
with Pulley of Takeup Reel Table.
MECHANICAL ADJUSTMENTS
PINCH ROLLER TENSION
Pinch \
Roller
( Pinch Roller Lever)
Fig. 1
Instruments Required: Spring Scale; Strong Twine.
Measurement: Refer to Fig. 1.
1. Load the tape as in the case of Playback, and set
the Tape Recorder in Record or Playback mode.
2. Hang a loop of twine on the Pinch Roller Shaft and
hook the Spring Scale on the other end of the loop.
3. Pull the Spring Scale in the direction of a line connecting
the centers of the Capstan and Pinch Roller Shaft,
and Pinch Roller Shaft, and increaring the pull slowly
read the scale at a point where the tape stops moving
by the pull.
4. The standard pressure of the Pinch Roller Shaft
should be:
1-7/8 ips..........ceeeee 5.3~7.40zs. (150~210 g)
3-3/4 ips... 5.7~8.5 ozs. (160~240 g)
ADJUSTMENT
Adjust the Pinch Roller Spring to the standard pressure
accordingly.
TAPE PAD PRESSURE
Tension
Gauge

Tape Pad
Arm Spring
Fig. 3
Instrument Required: Tention Gauge
Measurement: Refer to Fig. 2. and 3.
1. Set the Tape Recorder in Playback mode without
loading the tape.
2. Hook the Tension Gauge on the Tape Pad for the
Record/Playback Head at the center and lightly pull the
gauge so that the pad parts from the head. Take the
reading just at the point where the pad parts from the
head.
3. The standard pressure of the pad for the Record/
Playback Head should be:
0.2~0.50zs. (6~14g)
ADJUSTMENT
Adjust the Tape Pad Arm Spring to the standard pressure.
WINDING TORQUE FOR PLAYBACK AND FAST
FORWARD
Takeup Reel }
ee
Tape.
Flywheel) > Tape)- ere U
Clywheel) 7 ay eo ae )
‘Tension’
[eae z |
Cressure Roller Le
(Splicing Tape) 7 (~ \ Gauge
Fig. 4
Instruments Required: Tension Gauge; Splicing Tape
Measurement: Refer to Fig. 4.
1.-Make a loop of the tape (5” reel) end, fasten the
looped end with the splicing tape, and put the reel
on the Takeup Reel Table.
2. Hook the Tension Gauge on the loop and pull out 6
inches or so of the tape end.
3. Set in the Playback or Fast Forward mode, and pull
the Tension Gauge in the direction of winding keeping
the pace with the moving tape until the reading of
the Tension Gauge remains constant at which point
take the reading. Repeat this for several times and
take the average for a correct torque.
4. The above test should be made with 5” tape reel
with full load.
5. The standard torque should be:
Playback.............. 0.53~0.71l ozs. (15~20g)
Fast Forward......... 0.7l ozs. ~ (20g~)
ADJUSTMENT
Reel Table Decorative \
Screw J
Reel Table Spring
Reel Table
F.F.Fiber
Washer
F.F.F iber
Washer
Friction Washer
rT Friction =o
Friction Pulley Friction Pulley Nut
Tetoron Washer
Fig. 5
Adjust the torque with the Friction Spring on the Takeup
Reel Table. If the torque is too strong, loosen the Friction
Spring, and if too weak tighten it. If the Friction Washer
gets oily clean it immediately to prevent slip. If the tension
of the Takeup Belt is weakened the winding torque
drops.
BACK-TENSION FOR PLAYBCK
ee
Tension
Gauge
Fig. 6

Instruments Required: Tension Gauge; Splicing Tape
Measurement: Refer to Fig. 6.
1. Measure the back-tension in the manner similar to the
winding torque for Playback, but in this case by
pulling the tension gauge on the 5” tape loaded on
the Supply Reel Table.
2. Measure the back-tension for Playback with 5” reel
fully loaded.
3. The standard back-tension should be:
0.05~0.25 ozs. (1.5~6.5 g)
ADJUSTMENT
Too strong back-tension may be caused by the accumu-
lation of dust on the turning parts of the Rewind Pulley
and Supply Reel Table, requiring occasional cleaning. Too
weak back-tension may be due to the weakened tension
of the Rewind Belt and it should preferably be replaced
then.
MOTOR SHAFT PRESSURE AGAINST FLYWHEEL
~~ Motor Spring ;
(Tension Gauge)
(Flywheel)
Fig. 7
Instrument Required: Tension Gauge
Measurement: Refer to Fig. 7.
1. Load the tape and set the Tape Recorder in Playback
mode. Hook the Tension Gauge on the end of the Motor
Spring attached to the Motor (see the drawing).
2. Pull the Tension Gauge opposite to the action of the
spring and increase the pull until the Flywheel and the
Motor Pulley part from each other at which point take
the reading. The tape stops then.
3. The standard pressure for the Motor:
2.5~3.5 0zs. (70~100 g)
ADJUSTMENT
Adjust the motor spring for correct pressure.
HEAD ADJUSTMENTS
Relative positions of heads and tape,
Adjust the relative positions of Record/Playback head
and Erase head as shown in the drawing.
Improper relative positions of these heads causes imperfect
erasure and cross-talk, and the slightest displacement of
the mounting may lead to the lowe position of the head
in respect of the tape. Close adjustment is therefore
necessary.
0.04~0.16 O~0.12
Erase
Head Record/Playback
Head
Fig. 8
Unit: Inch -
HEAD AZIMUTH ADJUSTMENT
Slit Head Adjustment Screw
Deflection of the angle of the head slit from vertical will
deteriorate high frequency characteristic on playing back
the tape with recording made with another Tape Recorder,
while it is not so important with the tape recorded and
played back on one and the same Tape Recorder. The higher
the deflection, the poorer the poorer the perfomance.
To prevent this trouble, the slit of the head should be
maintained precisely at right angles to the path of the
tape.
Connect the Vacuum Tube Voitage Meter (V.T.V.M.) with
8 © Resistor in parallel to the Monitor Jack, and playback
the standard alignment tape (tape with recording of
signals, 3,000 cps. at 3-3/4 ips. on vertical slit ).
Adjust the angle of the head slit to be precisely vertical
by turning the adjusting screws so as to obtain the
maximum output signal.
When the Record/Playback Head is replaced it must be
adjusted as described above.
TREATMENT AFTER ADJUSTMENT
Lacquer-lock all the holding and adjustng screws of the
heads after the adjustment has been completed.