Akai 1730-SS

VI. MECHANISM ADJUSTMENT
1. PINCH WHEEL ADJUSTMENT
It is important that the pinch wheel shaft be kept in
perfect alignment with the capstan shaft. 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 will result in wow and flutter. Check pinch
wheel pressure with a spring scale, and if necessary,
adjust the pinch wheel load spring.
2. TAKE-UP IDLER WHEEL ADJUSTMENT
The take-up idler wheel must be kept in perfect
alignment with the take-up reel shaft. In fast forward
operation, the idler wheel contacts the upper knurled
wheel of the take-up reel shaft assembly, and conversely
contacts the lower knurled wheel during record or play
operation. 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.
Slippage occurs if the pressure is less than specified.
Sit ings cece
reel shaft ring -——— ~~
reel spring ~—
reel retainer
i
3R O ring
mibber plate, reel table - -~
reel shaft B
reel table B, w/shaft A~-@
rubber ring
ss take-up roller A
rewind drive putley-———
spring G-2—~
})—~-—- take-up roller D
Reel
table
spring
plate
A
———aS
72
washer ——————~<25>
thrust washer
washer —
reel
table
thrust
retaining
pin
———~ES>
washer ————--—-->
washer
aD
i
Cz ae
XR
reel
bearing
plate
———
So
washer —— |
“ES ring -——_——--.—
spring
F-4
—-—--
-.
F
ft -—_—— washer
washer
BAY
a
reel
table
spring
plate
C
€————___washer
= —- retaining pin
set sleeve B — == - i
ae)
Set
Serewen-—
+
ge
;
reel
table
pultey
i
|
{
Be
wh
screw
Fig. 1
3. REWIND IDLER WHEEL ADJUSTMENT
The rewind idler wheel must be kept in perfect alignment
with the rewind reel shaft. The amount of pressure on
the knurled motor bushing should be about 50 grams
during rewind operation. Adjust both the idler load
spring and rewind roller.
4. INTERMEDIATE WHEEL ADJUSTMENT
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. In rewind
mode, it contacts these parts while simultaneously
transmitting motor torque. An adequate pressure is 50
grams. Adjust the load spring of the intermediate wheel
if the pressure is not sufficient.
5. TAKE-UP REEL SHAFT ASSEMBLY
ADJUSTMENT
A felt clutch is attached to the bottom side of the reel
table base plate so that recording tape will not stretch
due to excessive tension during fast forward operation.
To check the amount of friction on this part, install a
5-inch ree] with a 60 mm diameter tape and gently pull
the end of the tape upward with a spring scale. Adjust
the conical spring so that the amount of tension on this
part is between 350 to 450 grams. Another felt clutch is
attached to the take-up drive wheel to provide proper
slippage during record or play mode. The procedure for
checking friction of this part is the same as the foregoing,
and between 150 and 200 grams of friction provides the
best results. Adjust the star-shaped spring just under the
take-up drive wheel. During rewind operation, the
amount of friction of this part will decrease to 10 to 15
grams. Check to see whether this is satisfactory. If not,
readjust the star-shaped brake spring and the pressure of
the spring retainer washer accordingly.
6. SUPPLY REEL SHAFT ASSEMBLY
ADJUSTMENT
A felt clutch is used between the lower side of the reel
table base plate and the rewind rubber ring to protect
the recording tape from excessive tension during record-
ing. To check the amount of friction on this part, install
a 5-inch reel with a 60 mm diameter tape, and gently
pull the end of tape upward with a spring scale. Adjust
the conical spring so the tension is between 350 and 450
grams. Another felt clutch is attached to the rewind
drive wheel to provide proper slipping operation during
record or play mode. The procedure for checking
friction on this part is the same as the foregoing, and
between 110 and 130 grams of friction gives best results.
In fast forward operation, the amount of friction will
decrease to 10 to 15 grams.
Check to see whether this is correct. If not, readjust coil
spring and spring retainer washer. (See figure 1 (a) at
left).
re py
12