Mechanical Adjusim' Efi - Sharp GF-500 Service Manual

P I N C H R O L L E R P R E S S U R E C H E C K
1. Place the unit in PLAY mode.
2. Push the pinch roller, at the point shown in Fig. 9-1, by
using a tension gauge (500 gr.) so that it will come off the
capstan. Then, release the tension slowly until the pinch
roller hits the capstan again (i.e., the pinch roller is about to
rotate again). Then check the tension gauge is reading
350 gr. to 420 gr.
3. If the reading is outside the range of 350 gr. to 420 gr.
replace the pressure spring of the pinch roller.
T O R Q U E C H E C K A T P L A Y , F A S T F O R W A R D A N D
REWIND MODES
Put a torque meter cassette in the cassette compartment of the
set, and see that the measured torque in each mode is normal
as follows:
TAPE SPEED ADJUSTMENT (See Figs. 9-2 and 9-3)
Note:
The high speed operation has priority over the normal speed
operation, and so try to do the adjustment for the former first
and then for the latter.
For High Speed Operation
1. Connect a wow/flutter meter to the Line Output socket
across a 100K ohm resistor, and shortcircuit the deck 1
control terminal (TP503).
2. Play a test tape (TEAC, MTT-118, 1 kHz prerecorded) - at
its middle part but not at its start or end point.
3. Adjust the semi-variable resistors (VR501 for the deck 1
and VR502 for the deak 2) located on the deck 1 and deck
2 mechanism P.W. Boards, so that the output frequency is
1 9 9 0 t o 2010Hz for the deck 1 and 1980 to 2000Hz for
the deck 2.
For Normal Speed Operation:
1. Play a test tape (TEAC, Ml-T-1 11,3kHz prerecorded).
2. Adjust the semi-variable resistors (VR503 for the deck 1
and VR504 for the deck 2) located on the deck 1 and deck
2 mechanism P.W. Boards, so that the output frequency is
2985 to 3015Hz on the wow/flutter meter for both decks 1
and 2.
R E C O R D / P L A Y B A C K H E A D A Z I M U T H A D J U S T M E N T
1. Make Connection of instruments as shown in Fig. 9-4.
2. Set the Dubbing switch SW201 to the off position and Tape
Selector switch SW105 to Normal position.
3. Adjust the head azimuth adjusting screw so that sine
waveform attains the maximum and the same phase in right
and left.
4. Even without using the oscilloscope, also adjust the head
azimuth adjusting screw so that outputs of both the right
and left channels attain the maximum and the same phase
in right and left.
Note:
For some heads, there may be a phase difference between
right and left channels when the output is made maximum.
In this case, adjust the head azimuth so that such phase
difference will be as small as possible while keeping the
output still maximum.
Pinch Roller
Figure 9-l
Torque meter
Mode
cassette
Playback
Fast-forward
Rewind TW-223 1
Figure 9-2
Figure 9-3
Test Tape
Figure 9-4
Pressure Spring
Measured torque
35 - 6 0 gram-cm
9 0 - 135 gram-cm
90 - 135 gram-cm
Oscilloscope
E . V .
as small as possible