Akai M-7 - Page 10

VL
ADJUSTMENT
OF
TAPE
TRANSPORT
UNIT
1. ADJUSTMENT OF PINCH WHEEL
It is important that the pinch wheel shaft be kept in
complete alignment with the capstan shaft. A proper
pinch wheel pressure is between 1,000 and 1,150 grams
when the unit is operated at the tape speed of 7-1/2
ips. Any deviation from this specification will result
in wow and flutter. Check pinch wheel pressure using
a spring scale and, if necessary, adjust the pinch wheel
load spring to suit.
2. ADJUSTMENT OF TAKE-UP IDLER WHEEL
The take-up idler wheel must be kept in complete
alignment with the take-up reel shaft. When the unit is
set in fast forward condition, the idler wheel will contact
to the upper knurled wheel of the take-up reel shaft
assembly, and it will contact to the lower knurled wheel
during record or play mode. Adjust idler wheel load
spring so that the idler wheel pressure is kept between
50 and 80 grams. The idler wheel wears rapidly if the
pressure is excessive, and slippage occurs in case the
pressure is smaller than the specification.
(8) Take—up reel shaft assy. (b) Rewind reel shaft assy.
reel shaft
reel stopper
reel aie
ree] table
base plate”
felt clutch
drive shaft --
fast iwd, wheel
conical spring rises
felt cluteh melee
retainer
GA
eer
—
CRETE
4
star—shaped
seasher
pes
retainer
:
nylon
washer
"=>
metal
washer
=
reece
Freesat
oilite
metal
—
ops
_-—
may
place
Spa
tne
metal
Ba
star~shaped
spring for
brake
rewind rubber ring
paper iene ae
retainer an ‘
Fig. 10
E E
iS 5
x
S
Recording
Tape
25mm
=
=
{{j,
0.3mm
Rec / Play Head
\_|
aogd
I
Rec/ Play Head
Ln
Erase Head
Fig. ll
Bias Head
3. ADJUSTMENT OF REWIND IDLER WHEEL
The rewind idler wheel must be kept in complete align-
ment with the rewind reel shaft. The amount of pressure
to the knurled motor bushing should be maintained
about 50 grams during rewind operation. Adjust both
the idler load spring and rewind roller.
4, ADJUSTMENT OF INTERMEDIATE WHEEL
The intermediate wheel is located between the rewind
idler wheel and the rubber ring which is used on the
upper part of the supply reel shaft assembly. When the
unit is set in rewind mode, it will contact to these parts
simultaneously delivering torque of motor. An adequate
pressure to be kept is 50 grams. Adjust the load spring
of the intermediate wheel in case the pressure is not
sufficient.
5. ADJUSTMENT OF TAKE-UP REEL SHAFT
ASSEMBLY
A felt clutch material is attached to the bottom side
of the reel table base plate so that recording tape will
not be stretched during fast forwarding operation due
to excessive tension. To check the amount of friction ¢
this part, place onto the take-up reel table a 5-inch ree.
with recording tape wound by 60 m/m in diameter, and
gently pull the end of tape upward using a spring scale.
Adjust the conical spring so that the amount of tension
at this part will be kept between 400 to 500 grams.
Another felt clutch material is attached to the take-up
drive wheel. It is used to provide proper slipping opera-
tion during record or play mode. The procedure for
checking friction of this part is same as the foregoing,
and between 120 and 200 grams of friction will provide
the best result. Adjust the star-shaped spring immediate
below the take-up drive wheel. When the unit is set in
rewind mode, the amount of friction of this part will
greatly be reduced and will become 10 to 20 grams.
Check to see if this is satisfactory and, if not, readjust
the star-shaped spring for Brake, and spring retainer
washes accordingly. (See figure 10 {a} at left)
6. ADJUSTMENT OF SUPPLY REEL SHAFT
ASSEMBLY ;
A felt clutch material is used between the lower side
of the reel table base plate and the rewind rubber rir
to protect recording tape from an excessive tension whi.
rewinding operation. To check the amount of friction
of this part, place onto the supply reel table a 5-inch
reel with recording tape wound by.60m,m in diameter
and gently pull the end of tape upward using a spring
scale. Adjust the conical spring so that the amount of
tension be kept between 400 an 500 grams. Another
felt clutch is attached to the rewind drive wheel and is
used to provide proper slipping operation during record
cr play mode. The procedure for checking friction of
this part is same as the foregoing, and between 80 and
120 grams of friction will give the best result. When the
unit is set in fast forward mode, the amount of friction
will greatly be reduced and will become 10 to 20 grams.
Check to see if this is proper and, if not, readjust coil
spring and spring retainer washer to suit.
7. ADJUSTMENT OF TAPE HEAD
(See figure 10 (b) at left)
A vertical azimuth alignment of tape head is the only
adjustment that can be made at the field of service. To
align tape head, play 8,000 cycles recorded on ar
Ampex standard alignment tape. Rotate the azimu.
alignment screw until a maximum playback level through
the small hole which is positioned on the shield cover of
the tape head assembly.
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