Teac A-650 User manual

• ■
-
HMM
TEAC
Stereo Cassette Deck with Dolby System
GENERAL INTRODUCTION
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'O q
NOTE
When ordering replacement parts, please refer to the
PARTS IST which is printed separately from this
manual.
? 1
■■■
! in
; TEAC CORPORATION [
51031740
If any of the adjustments or repairs seem too complicated
or are difficult for you to accomplish, please contact the
nearest TEAC Factory Service Department or write directly
to a TEAC office, the addresses of which are printed on the
back cover.
This Service Manual is designed to provide up-to-date
information to assist the skilled service technician to prop 
erly repair, adjust and maintain the TEAC A-650 Stereo
Cassette Tape Deck.
The A-650 is a high quality deck designed to be used as an
indispensable part of a superior home stereo system. It
contains a 2-motor transport utilizing a DC reel motor and
a Phase ocked oop (P ) servo motor, push button
control panel, Memory Counter with Play feature, Record
Mute feature, advanced Dolby NR circuitry, Peak indica 
tors, imiter, 3-position BIAS and EQ selector Switches, as
well as many of the standard TEAC features.
a
■ - . fc..
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■ 9
* Noise reduction circuit made under license from Dolby
aboratories Inc. The word “ Dolby ” and the Double-D
symbol are trademarks of Dolby aboratories Inc.

TABLE OF CONTENTS
21
3
1. Test Equipment Required
4
2. Specifications & Service Data
6
3.
Parts ocation
24
6-3-5.
32
33
Block Diagram
16 7.
5-8.
evel Diagram
34
8.
Trouble-Shooting
35
9.
2
5-9.
5-10.
5-11.
5-12.
5-13.
5-14.
19
20
16
16
TEAC Test Tape
ubrication ............................................
Torque Measurement using the Cassette
Torque Meter
Visual Index (for 5-6, 7, 8, 11 Sections)
Voltage and Frequency Setting
Playback Performance
Record/Playback Head Azimuth
Adjustments ................................
Specified Output evel Setting . .
Frequency Response -Playback- . .
Signal to Noise Ratio -Playback- .
5
11
13
15
17
7
7
7
7
8
8
8
9
9
10
10
11
11
4-1.
4-2.
4-3.
4-4.
4-5.
4-6.
4-7.
4-8.
4-9.
4-10.
4-11.
4-12.
6-2.
6-2-1.
25
25
25
26
27
27
28
28
29
29
30
31
6-2-2.
6-2-3.
6-2-4.
6-2-5.
6-2-6.
6-3.
6-3-1.
6-3-2.
6-3-3.
6-3-4.
5-1.
5-2.
5-3.
54.
5-5.
5-5-1.
5-5-2.
5-6.
5-7.
12
12
12
13
13
14
14
14
15
6-4.
6-4-1.
6-4-2.
6-4-3.
6-4-4.
6-4-5.
6-4-6.
6-4-7.
6-4-8.
6-4-9.
. . 21
. . 22
22
. . 23
VU Meter Calibration -Playback- .... 23
Headphone Output evel Checks .... 23
Monitor Performance 24
Minimum Input evel Checks 24
Specified INE Control Setting 24
VU Meter Calibration -Record- 24
ED Peak evel Indicator
Calibration
DO BY NR COPY-OUT-FM
Switch Function Check
Recording Performance
Bias Trap Adjustments
Record Bias Setting
Record evel Setting
Distortion Checks
Frequency Response -Overall- .
Signal to Noise Ratio ■ Overall-
Dolby NR Effect Measurement
Peak imiter Efficiency Checks
Erase Efficiency
6-4-10. Channel Separation
6-4-11. Adjacent Track Crosstalk
Measurement
4. Partial Disassembly of Main Parts
Case/Front.Panel
Tape Transport Chassis Removal . . .
Partial Rotation of Front Chassis . . .
Head
Pinch Roller
Cassette Holder
Capstan Motor
Capstan Drive Ass ’ y/Drive Belt . . . .
Reel Motor .......................................
Brake Plate Ass'y
Reel Tables ........................................
Idler Ass ’ y
5. Mechanical Checks and Adjustments
Take-up Torque .................
Fast Forward & Rewind Torque . . .
Pinch Roller Pressure
Brake Tension
Tape Speed/Wow and Flutter
Tape Speed
Wow and Flutter
Flywheel Bearing Adjustment
CASSETTE IN Switch Position
Adjustment
RECORD SAFETY Switch
Position Adjustment
Cassette Holder Motion Checks ....
Oil Retaining Washer Clearance
Check 16
Eject ock ever Adjustment 17
Pushbutton Control Checks 18
Auto-End Stop Facility Check 19
Memory Device Function Checks .... 19
6. Electrical Checks and Adjustments
6-1. Adjustment ocation

1. TEST EQUIPMENT REQUIRED
Spring scale: 1.
4.
*
Fig. 1-1 Spring Sca e & Cassette Ree Adapter
Fig. 1-2 P astic A ignment Too
Fig. 1-3 E-3 Head Demagnetizer
Fig. 1-4 TZ-261 Tape Recorder C eaner Kit Fig. 1-5 TZ-255 Oi Kit
3
0 — 100 g- cm (0 - 1.4 oz- inch)
0-160 g-cm (0 — 2.2 oz-inch)
5.
6.
7.
8.
9.
2.
3.
TEAC E-3 or equivalent
TEAC TZ-261 Tape Recorder Cleaner kit or pure alcohol
TEAC TZ-255 Oil kit or equivalent
0 - 70 g (0 - 2.5 oz.)
0 - 200 g (0 - 7.0 oz.)
Spring scale:
Wow/flutter meter:
Frequency counter.
AF oscillator:
AC VTVM:
10. Attenuator:
11. Distortion analyzer:
12. Oscilloscope:
13. Band-pass filter:
14. Test load resistor:
15. Plastic alignment tool.
16. Head demagnetizer:
17. Cleaner:
18. Oil
For take-up torque check:
For fast forward & rewind torque checks:
String: ength: about 50 cm (20 ” )
Cassette Reel Adapter: Diameter: 22 mm
* The tools above (1 - 3) are constructed as shown in Fig. 1-1.
Cassette Torque Meter: For take-up torque check:
For fast forward & rewind torque checks:
Use of the Cassette Torque Meter instead of the spring scale, if you have one, is recommended for easier
measuring. (See Fig. 5-3 on page 13.)
When ordering Cassette Torque Meter, allow for longer delivery' time that is required for it.
For Pinch Roller pressure check: 0 - 1 kg (2.2 lbs)
MEGURO DENPA SOKKI K.K., Model MK-668A or D & R Co.. Model F -4B.
Digital type, capable of 10 Hz to 100 kHz indication.
10 Hz - 100 kHz
0.1 mV - 300 V
General Purpose
Basic frequency 400 Hz/1 kHz
General Purpose
1 kHz narrow band-pass type
Non inductive type 8 ohm/1 W

2. SPECIFICATIONS & SERVICE DATA
SPECIFICATONS
or more)
Equalization
Head Configuration
2 Motors
TEAC TEST TAPE
0 dB = DIN Reference level (333 Hz)
REMARKS:
MTT-lli:
MTT-502:
MTT-150:
MTT-116K:
MTT-116U:
14 kHz/ — 24 dB
Fig. 2-1 TEAC Test Tape
4
Track System
2 Heads
Type of Tape
Tape Speed
Inputs
(level and impedance)
Outputs
(level and impedance)
Power Consumption
Weight
Bias Frequency
Operating Position
Power Requirement
For BIAS 1/EQ 1 (CrO 2 )
For BIAS 2/EQ 2 (Fe-Cr)
For BIAS 3/EQ 3 ( ow Noise.
High Output tape)
4-track. 2-channel stereo
Erase and Record/Playback
Cassette tape. C-60 and C-90 (Philips type)
4.8 cm/s (1 -7/8 ips)
Microphones: Min. input level: — 67 dB (345 m V)/(10 kohms
ine: Specified input level: — 9 dB (274 mV)/(50 kohms)
Min. input level: — 19 dB (86 mV)
DIN*: Min. input level: — 35 dB (13.7 mV)
DO BY FM/COPY: FM: -17 dB (109 mV)
COPY: — 9dB(274 mV)
ine out: Max. output level: +1 dB (0.869 V)/(into 50 kohms)
Specified output level: — 5 dB (435 mV)
Headphones: Specified output level: — 15.7 dB (130 mV)/(8 ohms)
EQ 1: 3180 ms + 70 ms (for CrO 2 tape)
EQ 2: 3180 ms + 70 ms (for FcCr tape)
EQ 3: 3180 ps + 120 ms (for regular Hi-Fi tape)
1/2-track. 1 -channel Erase Head
1/4-track. 2-channel Record/Playback Head
1 Phase ocked oop Servo Controlled DC Capstan Motor
1 Mechanical Governed DC Reel Motor
100 kHz
Horizontal
1 00/1 17/220/240 V AC, 50/60 Hz (General Export Models)
117V AC, 60 Hz (USA/Canada Models)
220/240 V AC. 50 Hz (Europe Model)
240 V AC. 50 Hz (Australia Model)
35W
13 kg (28% lbs.) net
For playback performance alignment
• For Dolby level calibration
• Dolby B-type tone (400 Hz tone).
200 nWb/m
• For frequency response test for EQ 1 &
2 (CrO 2 & Fe-Cr)
• 3180 ms + 70 ms
• 315 Hz/ — 4 dB. 31.5 Hz ~ 14 kHz/-24 dB
• For frequency response test for EQ 3
(Hi-Fi tape)
• 3180 ms + 120 ms
•315 Hz/-4dB.3I.5 Hz
For tape speed & wow/flutter test
• For Playback method
•3.000 Hz/- 10 dB
• For Record/Playback method (blank tape)
For record performance alignment (blank tape)
MTT-505B or similar:
MTT-504 or similar:
MTT-501 or similar:
NOTE: The TEAC test tapes require longer delivery time
titan regular parts.
* Pursuant to DIN Standards

SERVICE DATA
F c
o
■1HH
\ ‘ ,: C
©
E
o
Fig. 2-2 A-650 Dimensions
5
330nvn
Erase Efficiency
Channel Separation
Crosstalk Between Adjacent Tracks
Total Harmonic Distortion
Electrical
Frequency Response
Signal to Noise Ratio
Mechanical
Tape Speed Deviation
Tape Speed Drift
Wow and Flutter
Pinch Roller Pressure
Reel Torque
Fast Winding Time
End-stop Activate Time
Refer to frequency response limits charts on page 22 and 28
Playback method: CrO? & Fe-Cr tapes: 48 dB (minimum)
Hi-Fi tape: 46 dB (minimum)
Record/Playback method: CrOj & Fe-Cr tapes: 46 dB (minimum)
Hi-Fi tape: 44 dB (minimum)
With Dolby Noise Reduction used for recording and playback, S/N
ratio is improved by 5 dB at 1 kHz and 10 dB at frequencies over 5 kHz.
65 dB minimum
30 dB minimum (at 1 kHz)
40 dB minimum (at 125 Hz)
BIAS/EQ 1: 2.5% (maximum)
BIAS/EQ 2: 2.5% (maximum)
BIAS/EQ 3: 2.5% (maximum)
440mm
.7-V
T-S93
NOTE: • Improvements may result in Specifications and Service Data changes.
• Value of “ dB ” m tire Data refers to 0 dB = 0.775V, except where specified. If a Test Set or
VTVM calibrated to 0 dB = IV is to be used, appropriate compensation should be made.
3,000 Hz ±30 Hz
15 Hz
Playback: 0.07% (WRMS)
0.15% (RMS)
Record/Playback: 0.18% (WRMS)
400 g +20 g (13.5 ~ 15.0 oz)
Take Up: 40 ~ 70 g-cm (0.6 ~ 1.0 oz-inch)
Fast Forward: 100 ~ 1 50 g-cm (1 .4 ~ 2.1 oz-inch)
Rewind: 100 ~ 150 g em (1.4 ~ 2,1 oz-inch)
90 seconds for C-60
1.5 seconds ±0.5 seconds
]E
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©
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□□□
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E'ZZJ O O O
I ________

3. PARTS LOCATION
------ RECORD SOLENOID
MUTING PC BD. ------ -----
VU LEVEL METER PC BD.
HEAT SINK
POWER SUPPLY PC BD.
INPUT-OUTPUT PC BD
RECORD/PLAYBACK
amd ; Dr on
POWER TRANSFORMER
I6P CONNECTOR
CONTROL PC BD.
--------- TRAP COIL PC BD
REEL MOTOR
-------- LEVER SWITCH PC BD
HALL EFFECT ELEMENT
FLYWHEEL
I
7-576
Top View Fig. 3-1
SUPPLY REEL TABLE ----- -----
LED PC BD.
VU METERS
POWER SWITCH
MIC JACKS
ERASE HEAD
PHONES JACK
T-575
Front View
Fig. 3-2
6
1
I
DRIVE BELT ------
PAUSE SOLENOID -----
----- TAKE -UP REEL TABLE
CASSETTE
HOLDER
----- CAPSTAN MOTOR SERVO PC BD.
----- CAPSTAN MOTOR
’ i r?
' IB O;0l
J 3 ; f
eiiO
AMPL PC BD
DOLBY B TYPE
PROCESSOR PC BD.
9P CONNECTOR
! 1 ----- OUTPUT CONTROL
! * ----- LINE CONTROL
1 ----- MIC CONTROL
REC/PLAY HEAD -----
PINCH ROLLER ------
BUTTON ASSY -----

4. PARTIAL DISASSEMBLY OF MAIN PARTS
NOTE
3.
I.
4.
2.
4-1. CASE/FRONT PANEL
4-M4x10
3-B M3x6
A
Fig. 4-1
4-2. TAPE TRANSPORT CHASSIS REMOVAL
First do procedure in section 4-1.
I.
2.
3.
4.
4-BSB M3x6
G
First do procedure in section 4-1.
Fig. 4-2 Tape Transport Chassis Remova
7
4-3. PARTIAL ROTATION OF FRONT
CHASSIS
1.
2.
3.
4.
Most removal and replacement can be made with the Front
Chassis section (E) tilted in the forward direction, as ex 
plained in the preceding section .without removing tape
transport chassis (A) which is held in place by screws (F).
Disconnect the 16P Plug and the 9P plug. See Fig. 3-1
on page 6.
Unscrew the screws (B) (H) (C) (F) in that order and
loosen (D) to facilitate next step.
Tilt the Front Chassis section (E) forward and away
from the main chassis (G).
ift the tape transport chassis (A) from the main
chassis.
Use the proper tools. Demagnetize tire tools
before use.
When mounting or removing a spring, pay heed
to the position (direction) of the anchor or hook.
The wrong position may result in a change in the
tension.
BSB M3x6i
. '^ b
• 3-BSB M3x6
Case/Front Panel Removal
BSB M3x6'
c — r'
4-BSB M3x6<-
When reassembling, don ’ t forget to reinstall all
hardware such as springs and washers, etc.
For assembling hardware shape identification,
see ASSEMB ING HARDWARE CODING IST
in the Parts ist.
NOTE
When removing or installing the Front Panel, center
the levers of tire toggle switches on the Front Panel
to make the work easier.
4 E
D
Remove the parts in the following sequence.
Top Cabinet Ass ’ y (D)
Cassette Holder Cover Ass ’ y (A)
To remove the Cassette Holder Cover, do the following:
a. Depress EJECT lever.
b. Move the latch arm protruding from the top of tire
Cassette Holder Door to the left to release tire
Cover.
c. Allow the Cover to rotate outward on its hinge;
then lift up gently on the Cover to remove it from
the Door.
Knobs (C)
Front Panel Ass ’ y (B)
BSB M3x6
c>
, / B'SB,M3x3

4-4. HEAD
First do procedure in section 4-1.
1.
ERASE HEAD
O ’
2.
Fig. 4-3 Heads/Pinch Roller Replacement
4-5. PINCH ROLLER
First do procedure in section 4-1.
1.
REC/PLAY
ERASE
2.
T-463
Fig. 4-4 Head Wiring Diagram
A
4-6. CASSETTE HOLDER
First do procedures in section 4-1 and 4-2.
2-PSA M2.6x6
2-BSA M3x6
5.
6.
2-BSA M3x6
Fig. 4-5 Cassette Ho der Remova
8
Unsolder each lead wire from the terminal pins of tire
head to facilitate replacement. To re-solder each head
wire to the newly replaced head, refer to Fig. 44.
2. ift up the heads after taking off tire hardware mount 
ing them.
1.
2.
Remove the E-ring retaining the Pinch Roller Ass ’ y (A)
and remove the Spring (B) from the hook (C) of the
Head Base Plate and the tab of the Pinch Roller Ass ’ y.
Remove the Pinch Roller Ass ’ y from the pivot stud pin
of the Plate.
Take off the 2 screws (H) from the transport chassis.
oosen the 2 screw (G) to separate the Cassette Holder
Door (F) and the Cassette Holder (E).
Detach the Door (F) from the chassis.
Remove the Micro Switch Ass ’ y (B) to simplify the
next steps.
Take off the E-ring (A) to separate the Cassette Holder
(E) from the chassis.
Remove the Holder (E).
RED
WHT
GRN
BLU
3.
4.
NOTE
After replacement, always clean the driving surfaces
of the Pinch Roller with the TEAC TZ-261B Rubber
Cleaner or with pure alcohol, then proceed directly
to the PINCH RO ER PRESSURE adjustment
section. See page 13.
NOTE
1. After replacing the head, always adjust the head
alignment, especially the Record/Playback Head ’ s
azimuth (see 6-2-1), and then secure the screws
and/or the nut with a drop of locking paint.
Connect the wires to the head terminal pins
quickly to prevent breaking of internal wires of
the head due to overheating.
W-20
N - M *£vr'L
J©
O SW-20
B M2x4
2-B M2x4
O ’
REC/PLAY HEAD
.^W-20 '

4-7. CAPSTAN MOTOR
3.
B.
1.
3-BSA M3x6"
2.
Viewed from Rear
3.
Fig. 4-6 Capstan Motor Replacement
4.
4-8. CAPSTAN DRIVE ASS'Y/DRIVE BELT
First do procedures in section 4-1 and 4-3.
1.
2.
3-B M2.6x6x-
3.
Viewed from Rear
4.
5.
Fig. 4-7 Capstan Drive Ass ’ y/Drive Belt Replacements
6.
1.
1.
2.
2.
I. „
3.
4.
3.
9
Release the Drive Belt from the Motor Pulley.
oosen the two screws holding the P.C. Board insula 
tor, remove the insulator and then unsolder the wires
marked with asterisks (*) from tire PC Board (part of
tire Motor Ass ’ y). Note the color code and the position
of each wire prior to unsoldering the leads.
Remove the Motor Ass ’ y together with the PC Board
from the chassis by taking off the screws.
Remove the Control PC Board Ass ’ y (1) bj' taking off
tire 4 screws (J).
Detach the Flywheel Bearing Plate Ass ’ y (C) from the
mounting studs by unscrewing the 4 screws (H).
Take out the Drive Belt (E) from the Motor Pulley (B)
and the Flywheel (F).
Pull apart the Oil Retaining Washer (A) from the shaft
of the Flywheel.
Carefully lift out the Flywheel from the Capstan Hous 
ing Ass ’ y (C).
Remove the Capstan Housing Ass ’ y from the chassis
by unscrewing the 3 screws (D).
1.
2.
NOTE
Since the Capstan Drive Ass ’ y is a precision part,
TEAC specially distributes the Flywheel and the
Capstan Housing Ass ’ y as a whole assembly.
Hence, always replace the Flywheel together
with the Capstan Housing Ass ’ y.
Clean all driving surfaces of the Flywheel and the
Drive Belt with TEAC TZ-261 Cleaner kit ( “ A ”
for Flywheel. “ B ” for Belt) or with pure alcohol.
Do not bend the Capstan Shaft as this will in 
crease wow/flutter or speed deviation.
During re-assembly re-attach the Drive Belt with 
out twisting or stretching it.
z
4-B M3x6
First remove tire Top Cabinet Ass ’ y (see 4-1), then do
section 4-3.
UBRICATION:
For lubrication of the newly replaced Capstan Drive Ass ’ y,
the following should be observed.
Apply a drop of a light machine oil of good quality
(e.g.: TEAC TZ-255) with an oil applicator to the shaft
of the Flywheel and spread oil evenly over the shaft
with a flannel cloth. After installing the Flywheel, be
sure to clean the tape moving portion of shaft with
TEAC TZ-261 A Head Cleaner or with pure alcohol.
Apply a drop of the proper oil in the same way as
above to the innermost area of capstan shaft (next to
the Flywheel).
Apply a film of light grease to the well of the Flywheel
Bearing Plate (K).
NOTE
When re-assembling, clean the pulley and the Belt
with TEAC TZ-261 Cleaner kit ( “ A ” for the
Pulley. “ B ” for the Belt) or with pure alcohol.
Take off or remount the Motor Ass ’ y taking care
not to scratch or otherwise damage the Motor
Pulley.
When re-attaching the Drive Belt to the Pulley do
not twist or stretch the belt.
When remounting the PC Board be sure to install
the mica insulator between the transistor and the
PC Board mounting bracket.

4-9. REEL MOTOR
First do procedures in section 4-1,4-3 and 4-8.
1.
2.
-E
D
3.
4.
5.
H
6.
Viewed from Rear
Ree Motor Rep acement
Fig. 4-8
4-10. BRAKE PLATE ASS ’ Y
First do procedures in section 4-1,4-3,4-8 and 4-9.
1.
4.
Viewed from Rear
Fig. 4-9 Brake P ate Ass'y Remova
10
Remove the Spring (G) by unhooking each end from
the spring fastener on the chassis and the spring hook
on the Plate (F) respectively.
Detach the Plate (F) by unscrewing the 2 screws.
Remove parts (E) (D) (B) (A: Brake Plate Ass ’ y) illus 
trated all the way in that sequence.
Remove each Brake Shoe (C) from the Brake Plate
Ass ’ y .
2.
3.
NOTE
When remounting the Fast Wind Idler Ass ’ y (B), clean
the driving surface of the Idler with the TEAC TZ-
261 B Rubber Cleaner or with pure alcohol.
3-PSA
M2.6x6
O ’
| F
n
gf) E-2.5
sb
Remove whole Reel Motor Ass ’ y (J) from the mount 
ing studs by taking off the 3 screws.
Detach only the Motor body (1) by unscrewing the 3
screws from the Motor Base Plate Ass ’ y (H).
To further disassemble other parts illustrated in the
box area, do the following steps.
Take off the screw (A), then separate tire Fast Wind
Idler Ass ’ y (B) from the Plate Ass ’ y (H). Pay special
attention not to lose the Steel Ball (C).
Remove the Fast Wind Arm Plate (D) from the Plate
Ass ’ y .
Disconnect the Spring (G) from the spring hook of the
Tension Arm Ass ’ y (E), remove tire ‘ E ’ ring (F), then
lift off the Tension Arm Ass ’ y.
1 G ».
J
2-BSA
M3x6
A X JX... J
psa n /WY)
M2.6x8 U
S ’ I
jJ B2-PSA M
- t ^g'*M2.6x4 V'
I T 3-PSA
2.6x4 <^-
? j ©b

4-11. REEL TABLES
4-12. IDLER ASS'Y
First do procedures in section 4-1,4-2, 4-6 and 4-8.
First do procedures in section 4-1,4-3 and 4-8.
SUPPLY
Viewed from Rear
TAKE-UP
&
Viewed from Front
Fig. 4-10 Ree Tab es Rep acement
Fig. 4-11 Id er Ass'y Rep acement
LUBRICATION
b. CAPSTAN ASS'Y
1.
2.
Capstan Assy.
3.
a. FLYWHEEL ASS'Y
Cops ton Assy
T-40B
Fig. 4-12
Lubrication of Capstan Ass'y
11
r
i
Take off the screws mounting the Reel Table which requires
replacement.
1.
2.
3.
Remove Spring (C) from the mounting pin (A).
Remove E-ring (E) from the pivot pin (B).
ift out the Idler Ass ’ y (D).
App y I or 2 drops
(approx. O.2cc ) of Oi here
NOTE
Always replace tire complete Reel Table Ass ’ y as an
entire assembly, “ Take-up ” or “ Supply ” .
NOTE
ubrication should be generally done at about
every 1,000 hours of operating time of the tape
deck. Use high quality oil for this purpose.
For efficient oiling, it is recommended that
lubrication be done after nearly 1 hour of idling
of the deck, and while it is still warm.
Normally, it is necessary to lubricate only the
following two areas:
NOTE
When remounting tire Idler Ass ’ y, clean the driving
surface of the Idler with the TEAC TZ-261B Rubber
Cleaner or with pure alcohol.
6-B M2x5
S ’
6-SW 20
See Section 4-8 for lubrication of the newly replaced
Flywheel Assy.
Apply 1 or 2 drops (approx. 0.2 cc) of a light machine oil
with an oil applicator to the shaft bearing portion of the
I

5. MECHANICAL CHECKS AND ADJUSTMENTS
5-1. TAKE-UP TORQUE
Specification 40 ~ 70 g-cm (0.6 ~ 1.0 oz-inch)
Take-up Reel Table
Supply Reel Table
T-4O6
Take-up/Fast Forward Torque Measurement
Fig. 5-1
6.
Cossette Reel Adopter
7.
F
Spring Scole
&
8.
T-409
5-2. FAST FORWARD & REWIND TORQUE
Specification 100 ~ 150 g em (1.4
2.1 oz-inch)
Fig. 5-2 Torque Ca cu ation Method
6.
5.
12
4.
5.
3.
4.
T = F x r
T = torque (g-cm)
F = force (g)
r = radius (cm)
For example
If F = 36 g
T = F x r
= 36 x 1.1
= 40 (g-cm)
Consequently the torque is 40 g-cm
NOTE
Note that the Fast Forward and Rewind torque
should be measured before the Auto-End Stop Facil 
ity functions.
NOTE
All the mechanical checks and adjustments should be done
with the external Cases removed. (See Section 4-1).
1.
3.
SOX'
Remove the Cassette Holder. See 4-6 section on page 8.
Switch on POWER.
Set the Cassette Reel Adapter (22 mm Dia.), connected
to tire spring scale (0 — 70 g. or 0 ~ 2.5 oz.) by the
string as shown in Fig. 5-1 on the Take-up Reel Table.
Place die deck in the P AY mode.
Allow the rotation of the Reel Table to pull the scale
pointer toward the Adapter widi the spring scale
moving in the same direction at nearly the same speed
as die tape would be moved, and obtain the scale
reading. Make reading only when the pointer becomes
stable.
The scale should indicate Force of 36 ~ 64 g (1.3 ~
2.2 oz.).
This corresponds to a torque of 40 ~ 70 g-cm (0.6 ~
1.0 oz-inch). For the torque calculation, refer to Fig.
5-2.
If the reading is out of specified range, clean the
driving surfaces of the Reel Table Ass ’ y. and all other
driving parts relative to the take up torque function
with the TEAC TZ-261B Rubber Cleaner or with pure
alcohol.
If die above cleaning is ineffective for torque correc 
tion. replace the Reel Table Ass ’ y. (See Section 4-11).
If die indication is out of specified range, clean the
driving surfaces of the Reel Table Ass ’ y and all other
driving parts relative to the fast forward torque func 
tion with the TEAC TZ-261B Rubber Cleaner or with
pure alcohol.
Repeat die FAST FORWARD TORQUE procedure,
but use the Supply Reel Table and Rewind mode for
measuring the rewind torque.
2. The specified value is the same as that of the fast for 
ward torque.
5-2-2. REWIND TORQUE
1.
5-2-1. FAST FORWARD TORQUE
1.
2.
Cassette Reel Adopter (22mmDio)
Repeat step 1 and 2 in 5-1 section.
Set the Cassette Reel Adapter (22 mm Dia.), connected
to the spring scale (0 ~ 200 g. or 0 ~ 7.0 oz.) by die
string as shown in Fig. 5-1, on the Take-up Reel Table.
Place the deck in the Fast Forward mode.
Allow the rotation of die Reel Table to pull the scale
pointer toward die Adapter, and obtain the scale
reading. Do not read until the pointer becomes stable.
The scale should indicate 91 ~ 136 g (3.2 ~ 4.8 oz.).
Til is corresponds to a torque of 100 ~ 150 g em (1.4 ~
2.1 oz-inch).

The torque measurements
0
I*
Fig. 5-3 Cassette Torque Meter
5-3. PINCH ROLLER PRESSURE
Specification 400 g ± 20 g (1 3.5 ~ 1 5.0 oz.)
5.
T-S6O
6.
7.
S l
nr
Z3
Fig. 5-5 Switch Arm Location
5-4. BRAKE TENSION
t
Ji
(
4.
13
For fast forward and rewind
torque measurements:
3.
4.
1.
2.
3.
Switch on POWER.
Press the Switch Arm (A) shown in Fig 5-5 so that the
CASSETTE IN Switch (S509) (see Fig 5-11) will
activate.
Place the deck in the P AY mode with no tape loaded.
Attach the spring scale to the hole in the Pinch Roller
Ass ’ y as shown.
Gently draw the Pinch Roller away from the Capstan
shaft (in a direction parallel to a line that intersects the
centers of the capstan shaft and the Pinch Roller) until
die Capstan shaft and the Pinch Roller are completely
separated.
Gradually return the scale back until the Pinch Roller
just begins to rotate. The scale should then be reading
approximately 400 ± 20 g (1 3.5 ~ 15.0 oz.).
If die reading is out of specified range, adjust the
tension of die Pressure Spring by bending the tab of
the Pinch Roller Ass ’ y slightly.
1.
2.
C? / 33 .
T-620
Fig. 5-6 Brake Tension Adjustment
5
TORQUE MEASUREMENT USING
THE CASSETTE TORQUE METER
0 ~ 160 g em
(0 ~ 2.2 oz-inch)
By use of a Cassette Torque Meter, it is possible to direcdy
obtain die torque value without calculation, and to do the
measurement simply with no removal of any parts. If
repairs are necessary, the external Cases must be removed.
oad the Meter on the deck and read the pointer indication
on the dial scale for each tape movement operation.
•^■Bend here to adjust
can be easily done with the
Cassette Torque Meter indicated below.
For take-up torque measurement:
Switch on POWER.
oad a TEAC MTT-501 test tape.
Check for excess slack or tightness of the tape when
operation is changed from play, fast forward and re 
wind mode to stop mode, respectively.
If brake action is too “ tight ” or “ loose ” , adjust by
bending the amis of the -Brake Bracket in or out as
shown by the arrows in Fig. 5-6.
©
BE
0 ~ 100 g-cm
(0 ~ 1.4 oz-inch)
-V •7 ’ AV
Fig. 5-4 Pinch Roller Pressure Measurement
3a®
■ v . ..z.

5-5. TAPE SPEED/WOW AND FLUTTER
PLAYBACK METHOD
4.
5.
1.
2.
OSCILLATOR
WOW a FLUTTER METER
OVTPu ’
Il I
3.
Fig. 5-7 Tape Speed/Wow & Flutter Measurement Setup
5-5-1. TAPE SPEED
1.
2.
3.
4.
5.
6.
MOTOR-
5-5-2. WOW AND FLUTTER
Fig. 5-8 Tape Speed Adjustment Location
14
Specification:
Tape Speed Deviation:
Tape Speed Drift:
Wow and Flutter
After making the tape speed measurement, perform the
wow and flutter test using the Playback Method and the
Record/Playback Method successively.
Connect test equipment to the deck, except the AF
oscillator, as shown in Fig. 5-7.
Set the OUTPUT control on the deck to obtain conve 
nient output.
Set the EQ switch to the “ 3 ” position, and then load
and play a TEAC MTT-l 11 test tape (3,000 Hz signal is
recorded).
Adjust the semi-fixed resistor as shown in Fig. 5-8 for
reading of 3.000 Hz ± 5 Hz on the frequency counter.
(NOTE: This tape speed setting should be done after
approx. 30 seconds of operating time of the deck.)
Then, verify the reading on the frequency counter as
within the specified range of 3,000 Hz ± 30 Hz, and
the Tape Speed Drift is within 15 Hz at any portion
of the tape run.
If the tape speed is extremely out of the specification,
check the Pinch Roller pressure and the tape driving
function for correction, and make sure the tape path is
clean.
1.
2.
3.
Play the MTT-l 11 test tape.
Read the indication on the wow and flutter meter.
The wow and flutter value should be 0.07% WRMS,
max. or 0.15% RMS, max.
If the wow and flutter is out of specification, check
the Pinch Roller pressure and the take-up torque, see
that tire tape path is clean, and that the Capstan Belt
is not stretched or oily.
If tire above checks are ineffective for excessive wow
and flutter correction, repair or replace the Pinch
Roller, the Capstan Belt and/or any other defective
parts.
DECK
under TEST
3,000 Hz ± 30 Hz
15 Hz
Playback: 0.07% (WRMS)
0.15% (RMS)
Record/Playback:
0.18% (RMS)
FRE QUENCY COUN TER
■ ■ ■ ■ ■ I
o o I
NOTE
Before performing this adjustment, clean all parts
in the tape path, particularly the Capstan, the
Pinch Roller and the Heads with the appropriate
liquid from the TEAC TZ-261 Cleaner Kit or
with pure alcohol.
Wow and flutter should be checked in two ways;
Playback only and Record/Playback methods.
First correct tape speed and wow and flutter
using the playback only method. Then measure
wow and flutter using record and playback
method.
As the measured results may vary with respect to
location on tape at which it was taken, three
points — at beginning, middle and near the end
of the tape — should be measured. Tire worst
case reading must satisfy the specification.
1.3
Q O 0

RECORD/PLAYBACK METHOD
3.
1.
2.
5-6. FLYWHEEL BEARING ADJUSTMENT
1.
2.
3.
See also Fig. 5-9
Fig. 5-10
Flywheel Bearing Adjustment
15
4.
5.
6.
7.
8.
oad a TEAC MTT-502 test tape (blank) and set the
B1AS/EQ switches in the “ 3 ” positions.
Apply and record a 3,000 Hz signal.
Rewind and play this recorded section.
Read the indication on the wow and flutter meter.
The wow and flutter value should be 0.18%' RMS max.
If the measured value is out of specification, repair
using the same methods as stated in steps 4 - 5 in the
Playback Method procedure.
5-6. FLYWHEEL BEARING
/ADJUSTMENT (Fig. 5-10)
NOTE
When using this method, adopt the maximum wow
and flutter value obtained by repeated play and stop
modes of operation. This operation is necessary to
make sure wow and flutter content between record
and playback will not be in phase to create a false
reading.
Connect test equipment to the deck as shown in Fig.
Set INE and OUTPUT controls on the deck to obtain
convenient input and output levels.
Flyw heel
\ Thrust Adjusting Screw
Close the Cassette Holder with the Holder empty so
that the Switch Arm located on the top of the Cassette
Holder is not depressed and the Capstan Motor is not
turning.
Depress the PAUSE Button to engage the Play Sole 
noid.
By using a slot screwdriver with small blade, adjust the
Thrust Screw so that there is a gap of 0.1 to 0.3 mm
between the lower end of the Capstan Shaft and the
well of the Flywheel Bearing. This adjustment can be
made by pushing the Flywheel toward or away from
the front of the deck.
VISUAL INDEX (for 5-6, 7, 8, 11 Sections)
To readily locate the specified checkout areas described in
5-6, 7,8,11 Sections, refer to Fig. 5-9.
5-11. EJECT LOCK LEVER
ADJUSTMENT (Fig. 5-16)
I 5-7. CASSETTE IN SWITCH
POSITION ADJUSTMENT
(Fig. 5-11)
5-11. EJECT LOCK LEVER
ADJUSTMENT
(Fig. 5-15) r
Fig. 5-9 Visual index

1.
2.
3.
■Cassette Holding Arm
o
1.
RECORD SAFETY Switch
2.
3.
Record Safety Switch Positioning
Fig. 5-12
5-9. CASSETTE HOLDER MOTION CHECKS
Capstan Shaft
3.
4.
Safety Shaft
5.
Cassette Ho der Motion Checks
Fig. 5-13
Cassette Shell
Keep Proper Space
Fig. 5-14
16
I
Fig. 5-11
1.
2.
1.
2.
oad a standard shape cassette on the deck.
Make certain that both surfaces of the Oil Retaining
Washer are properly spaced from one side of the
Cassette Shell and the top end of the Capstan Housing
by rotating the Flywheel manually. See Fig. 5-14.
Micro Switch
Bracket
T-53O
Oi Retaining Washer C earance Check
Insert any cassette tape with the record protection tab
removed in the Cassette Holder and close Cassette
Holder.
Then, ensure that the Record Preventing ever moves
downward, thus closing the Record Safety Switch
(S512).
If the Switch does not close, loosen the screw fixing
tire Micro Switch Bracket and adjust the Switch posi 
tion by moving the Bracket for proper activation of the
Switch.
Be sure that when inserting any cassette tape in the
Cassette Holder and closing it, the Cassette In Switch
(S509) is actuated to run the Capstan Motor.
If the Capstan Motor does not rotate, loosen the screw
on the right end of the Micro Switch Bracket, and then
rotate the Bracket so that the Switch is engaged to ON.
After adjusting, retighten the loosened screw.
Capstan Shaft
Oil Retaining Washer
o
See a so Fig. 5-9 I T ’ 526
CASSETTE IN Switch Positioning
Micro Switch Bracket
Z CASSETTE IN Switch
Record Preventing Lever
5-7. CASSETTE IN SWITCH POSITION
ADJUSTMENT
5-10. OIL RETAINING WASHER CLEARANCE
CHECK
5-8. RECORD SAFETY SWITCH
POSITION ADJUSTMENT
!
oad the TEAC MTT-501 test tape or equivalent.
Ensure that when depressing tire Eject ever, the
Cassette Holder Door is opened smoothly without
binding from the closed condition.
Close the Cassette Holder with no Cassette in the
Holder.
Check that the Cassette Holder will open fully when
the Eject lever is depressed as above.
oad a cassette tape in the opened Cassette Holder
Door and check that the cassette shell does not come
into contact with the capstan shaft or safety shaft
fixed on the chassis.

5-11. EJECT LOCK LEVER ADJUSTMENT
Bent-tip of Record Preventing Lever
1.
2.
3.
Tab Hole
Fig. 5-15
Eject Lever
4.
Fig. 5-16
VOLTAGE AND FREQUENCY SETTING
JOO
D
/
1
3.
INCREASE
DECREASE
4.
5.
6.
7.
b. AC POWER LINE FREQUENCY ADAPTATION
Vo tage Se ector Setting Fig. 5-17
17
See a so Fig. 5-9
Record Protection Tab Location
1.
2.
Insert any cassette tape with the record protection tabs
removed, then close Cassette Holder Door.
Ascertain that when depressing the Eject ever, the
Cassette Holder Door is released from the ock ever
after the bent-tip of the Record Preventing ever is
extracted perfectly out of the tab hole of the Cassette.
If the bent-tip of the Record Preventing ever does not
fully clear the hole or the ock ever does not free the
Cassette Holder, make adjustment by bending the tab
of the ock ever in either direction as shown by the
arrows in Fig. 5-16.
Note that the ock ever must be allowed to open the
Cassette Holder after the Record Preventing Arm is
completely pulled out of the record protection tab
hole.
The Cassette Holder always should remain locked even
when any place on the Cassette Holder Door is pushed
toward the inside of the deck.
Disconnect the power cord of the deck from the source.
Turn the deck over and locate the voltage selector on
the bottom of the deck.
oosen the screw on the cut-out end of the metal bar
covering the voltage selector and then rotate the bar
so the slotted center post of the voltage selector can
be adjusted.
To increase the selected voltage, turn the slotted center
post clockwise using a screwdriver or other suitable
tool.
To decrease die selected voltage, turn the slotted
center post counter-clockwise.
The numerals that appear in the cut-out window of the
voltage selector indicate the selected voltage.
Re-install the metal bar.
Since the A-650 employs a P Servo DC Motor, 50 Hz
or 60 Hz operation is possible without power line fre 
quency adaptation.
a. VOLTAGE SELECTOR SETTING PROCEDURE
(FOR GENERAL EXPORT MODELS)
Lock Lever .
See also Fig. 5-9
Lock Lever Location

5-12. PUSHBUTTON CONTROL CHECKS
2.
2.
3.
3.
4.
4.
2.
3.
2.
3.
2.
3.
TEAC
A-650 Stereo Cossette Deck
m
rDOLBY NR t
LIMITER
BIAS EQ
oa ,. b
EJECT
STOP
Fig. 5-18
Front Panel View
18
□□□
The Fast Forward operation should be achieved by
pressing the Fast Forward Button only.
When the Fast Forward Button is depressed during any
other modes, the Fast Forward function should be
activated.
When either the PAUSE, Play, Rewind or STOP Button
is pushed, the Fast Forward mode should cease to
function.
Tire Rewind operation should be achieved by pressing
the Rewind Button only.
When the Rewind Button is depressed from any other
modes, the Rewind action should be achieved.
When either the PAUSE, Play, Fast Forward or STOP
Button is pushed, the Rewind mode should be released.
Play operation should be achieved by depressing the
Play button only.
When the Play Button is depressed during Fast For 
ward or Rewind operation, a delay time of 0.7 ± 0.3
second is required before Play mode is begun.
When the Play Button is depressed from any other
modes (with the exception of Record, Record Mut 
ing and Record Pause), the Play function should be
achieved.
When either Fast Forward, Rewind, PAUSE or STOP
Button is depressed, the Play mode should be dis 
engaged.
The PAUSE function should be engaged, only when
the PAUSE Button is depressed.
When the PAUSE Button is depressed from any other
modes, the deck should go into the Pause mode. (When
the PAUSE Button is depressed from the Record or
Record Mute mode, the machine should go into the
Record Pause mode.)
When either Play, Fast Forward Rewind or STOP
Button is depressed with the Pause facility engaged, the
Pause mode should be released.
STOP BUTTON
When the STOP Button is depressed from any other modes,
the selected operation mode should be released to stop tape
motion.
MIC
L/MONO
R
<s>
PHONES
The deck should go into the Record mode only when
a recordable tape is installed.
The Record mode should be achieved only when both
REC and Play Buttons are depressed at the same mo 
ment.
While the deck is running in the Play mode, when both
Play and Record Buttons are pushed together, the deck
should go into the Record mode. . . . Punch-in Record 
ing feature check.
When the Fast Forward, Rewind or STOP Buttons
are depressed during the Record mode, Record mode
should be released.
POWER
xx CH
n o»>
REC BUTTON
1.
PLAY BUTTON
1.
FAST FORWARD BUTTON
1.
REWIND BUTTON
1.
PAUSE BUTTON
1.
MEMORY
REC REC MUTE PAUSE
® ® ®
HOH

5-13. AUTO-END STOP FACILITY CHECK
i
2.
2.
1.
5-14. MEMORY DEVICE FUNCTION CHECKS
2.
3.
3.
3.
6. ELECTRICAL CHECKS AND ADJUSTMENTS
GENERAL NOTES
1.
5.
6.
2.
7.
3.
*
4.
*
19
The VTVM used in the procedures, including the
measurement at CA test points, must have load im 
pedance of 1MQ or more.
To correctly complete these performance checks, keep
the order as explained in this chapter.
All checks and adjustments should be made with Top
Cabinet removed. (See Section 4-1).
For each procedure, make the initial equipment test
set up, connections and switch/control settings as
shown in the associated illustrations.
Each of the switch settings marked with hyphen ( — ) in
the Switch Setting chart have no effect on the proce 
dures.
MEMORY P AY FUNCTION
Set the MEMORY Switch to P AY.
Depress the Index Counter reset button, depress
Play Button to run the tape forward until the Index
Counter indicates 003 or higher (but less than 900)
then depress Rewind Button.
Check that the tape stops for a short moment when the
Counter reaches 999, then the Play mode begins auto 
matically.
Before performing adjustments on the amplifier sec 
tion of this deck, thoroughly clean and demagnetize
the entire tape path, particularly erase head, record/
playback head, capstan shaft and pinch roller.
Make sure the deck is set for the proper voltage for
your locality.
In general, checks and adjustments for other than spec 
ified items, are done in the sequence of left channel
then right channel. Double designated REF. NO. in 
dicates left channel/right channel (example: VR 101/
201).
Value of “ dB ” in tire text refers to 0 dB = 0.775 V,
except where specified. If a VTVM calibrated to 0 dB =
1 V is to be used, appropriate compensation should be
made.
MEMORY STOP FUNCTION
Place the Switch in the STOP position.
Set deck in the Rewind mode with the Counter indicat 
ing 003 or a larger numeral (but less than 900).
Check that the tape halts when the Counter winds back
down to 999.
a.
1.
2.
b.
1.
2
EJECT LEVER
During the Play, Record Pause or Record Mute mode,
ensure that the EJECT ever cannot be depressed to
open the Cassette Holder.
The EJECT ever can be depressed to open the Cas 
sette Holder from the STOP. Fast Forward or Rewind
mode.
When the EJECT ever is depressed, be sure that the
Cassette Holder opens far enough, the lamp located at
the rear of the Cassette Holder is extinguished, the
Drive Motors stop and all control operations are
disabled.
Check that when the cassette reaches the end of tape
from each mode with the MEMORY Switch OFF.
the Take-up Reel stops rotating and the deck releases
the drive mechanism automatically.
The End-stop Activate Time (the time between the
stopping of the take-up reel table and stop mode of the
deck) should be 1.5 ± 0.5 seconds.
REC MUTE BUTTON
1. The Record Mute mode should be activated from only
the Record mode.
If the PAUSE, Play, Fast Forward, Rewind or STOP
Button is depressed, the Record Mute mode should be
disengaged.

6-1. ADJUSTMENT LOCATION
INPUT/OUTPUT PC BOARD
VR2O1
VR202
MUTE PC BOARD
CONTROL PC BOARD
r
— REC. EO
I II I. II III I 11 III I,
o
u
T-5B7
Fig. 6-1
Adjustment Location
20
VR101/201
VR1 02/202
VR 103/203
VR104/204
VR 105/205
VR 106/206
VR 1 07/207
VR1O8/2O8
VR601
VR602
Playback EQ
Playback level
VU meter calibration (Playback)
VU meter calibration (Record)
Record level (3)
Record level (2)
Record level (1)
Peak level indicator adjustment
DC 13 V adjustment
DC 24 V adjustment
VR760/860
VC60 2/601
VC604/603
VC606/605
L101/201
L703/803
L750/850
L75 1/851
L752/852
DOLBY FM/COPY calibration
Record bias (1)
Record bias (2)
Record bias (3)
Bias trap
Bias trap
Record EQ (1)
Record EQ (2)
Record EQ (3)
VR602
o
I
DC24VADJ
O
<
CD
£
0.
Ct
VR60)
g
I
DC 13V ADJ
Q
8
tn
o
z
m
8
O r — i
BIAS
TRAP
LIO!
I -------------------- 1
I DOLBY '
I FM/COPY CAL,
| l Ovnr6o|
I
I
L8O3 L7O3
|Q] [o]L
o o
R Q vrbbo !
I
PLAYBACK
EQ
■ PLAYBACK
LEVEL
I I
VR6O4
o
R
L meter J
ADJ
L750 L75I L752 LB52 L85l L85O
o. 'J, o, O. o,
1 ---- "-"E -
I i RECORD/PLAYBACK PC BOARD
L L
G O
VRKDI VRI02
I 2 3 3 2 1
G G G G O G
H- 1 R ~~
1 ------------ BIAS ADJ ------------ 1
_____ I
MOTOR SERVO
PC BOARD
G
TAPE SPEED ADJ
r
REC METER
CAL
POWER SUPPLY PC BOARD
VR6O3
G
3201 VR2
G G
R R
I
VC604 VC605 VC601
VC 602 VC 606 VC 603
VR2O5 © VR208 |
©3 — -i
VR203 VR2O4 VR2O6 | J
— r -> r I
R O O VR207 | L20I
I O' — ’ I fiR-,
? PLAYBACK REC
METER CAL CAL
1 O'-i
g VRI07
------- Q2 L
VRI03 VRiO4 VR !? 6
VR105 O VRI08