Garrard A70 Service Manual

Page 1

Garrard Service Sheet - Number 450

Model: Laboratory Series Auto Turntable mp'ememaryb

Sheets No.
...... 451
Type A. 70 to
...... 464
Subject: Index """"""""""""
INDEX
Sheel No. Subject
45 1 . . . - - - - Operation
452 - - - - - - - Installation
453 - - - - - - - Maintenance
454 . . - - - - - Adjustments
455 . . - - - - - Auto Trip
456 _ . . - - - - Turntable Speed
457 - - - - - - - Auto Switch
458 - - - - - - - Record Selection
459 _ . - . - - - Record Dropping
460 . . - - - - - Noise
461 . . - - - - - Pickup Head
462 - - . - - - - Motor
463 . . . _ . - - - Pickup and Arm
464 _ . . . - - - - Exploded View and

Spare Parts List

Page 2

Garrard Service Sheet - Number 452

Model: Laboratory Series Auto Turntable gfigeflexcfmaryto

Type A.7O j """ 461"":

Subject: Installation

UNIT ALREADY INSTALLED IN CABINET

Carry out the instructions given by the manufacturers of the complete instrument which
may include those concerning the auto turntable; in any case, the following points should be
checked.

See that all string, cardboard etc. used for packing purposes are removed, then release
the transit screws by screwing them down clockwise until the unit is floating freely on its sus-
pension springs. _

Due to its weight the heavy outer turntable may be packed separately and this should be
placed in position on the plastic foam mat over the inner turntable with the triangular mark
on each turntable facing the other. The triangular marks indicate the position at which the
turntable assembly is in balance and the correct assembly is shown on Diagram 3.

For transit purposes the heavy outer turntable should be removed.

To ASSEMBLE TURNTABLE MAT

Lay the mat flat on the turntable taking great care not to buckle the trim ring. Next,
carefully stretch the centre hole over the retaining ring in centre of turntable as shown in
Diagram 4. If located correctly the mat will run true.

Diagram 3 Diagram 4

FITTING T0 CABINET

The Auto Turntable Type A.70 is 15 long by 12% back to front and 2} below and 512-
above top of motor board. An additional l on the height and all round the edges is required
to permit the unit to float freely on its suspension springs. Also an extra 19; is required at
rm: and right hand side of pickup arm to allow clearance for counterbalance weight, see tem-
plate or refer to Diagram 7.

Page 5

PICKUP ARM AND BIAS COMPENSATOR

Unpack the pickup arm counterbalance weight and slide the weight on the rear of. the
pickup arm as in Diagram 2. Fit the counterbalance weight locking screw under the weight
with the rubber damping washer next to the screw head, then the metal washer. Temporarily
tighten this screw.

If the unit is received without a pickup cartridge, the cartridge of your choice should be
fitted using the hardware supplied with the pickup shell. See Sheet Number 461.

When the pickup head is in position see that the pointer on the side of the pickup arm,
indicating stylus pressure is set to the mark 0, i.e. no stylus pressure. It is set to this mark
by turning the adjusting screw under the arm in a counterclockwise direction, as seen from
above.

Next, with the pickup arm perfectly free to pivot up and down, adjust the position of the
counterbalance weight, by loosening its locking screw and sliding the weight along the arm
until the arm balances horizontally. Then tighten the locking screw.

The stylus pressure required is then applied by turning the adjusting screw under the arm
clockwise, each click representing an increment of approximately l gram and the markings
representing a range of' O to 5 grams.

The pickup arm has an inward bias which is related to stylus pressure. The longer arm of
the bias compensator, carrying a setting weight, is notched to correspond to the stylus pressure.
The notches represent 1 to 5 gams from inner to outer notch. The setting weight should be
set to the appropriate notch. Grip the side of the setting weight when adjusting its position and
do not slide it nearer to the arm pivot than' 15 necessary

654; 'F 7 fl . 7'6 H I} \r
216 *6 EXIREME Posmmor PICKUP \
All mums: BALANCE WEIGHTI * I >33I/s/\
1. - - as! _ r _ /
/ 8R MINIMUM \\//
/ 51::- 6 '5'; I746 CLEARANCE son PIEKW :Ht.
. . .. ARM coquER BALAN-L
I I :16 IIBR. Il/BR. R- WEIGHT
| 7 I, -
I e _ 4 ~
' 3/ 5%
I j._ - 6 4
I L j,
5 2 ' I,
l 5 a ._ 6532- _. $5
I 1 "
' 1 3-
Ifl J6" , . 5+
_ OSITION or ,
13. 'KJ TURNTABLE 1 I
I45 I SPINDLE |
_ I _ _ \ ,_ 7 , _ |
I, . k I
i I / SIIG DILHOLE TRANSIT
_ i ( SCREW POSITION j
I - ' , . '
| OUTLINE OF HOLE 3/2 s/Isnu.uota I
y I To BE CUT IN / TRANSlT I I
SCREW /
538 I MOTOR BOARD sum" IJ a»
a
I . 5116 I
a
l 714 I
| . ' |
0
I 47s l
\ 4-REcessesl mm 11450529 2? I
\\ 7L8 /
L4 \\ _______________________ /
l OUTLINE OF UNITJ % n-ZLq- -.
RECOMMENDED SIZE MOTOR BOARD-i FRONT
16 3/4

Diagram 7

Page 21

\ -3 i,
\J, ADJUSTMENT FOR

RECORD PLATFORM
POSITION

Diagram 11 Diagram 12