Fisher MT-750 - Arm Movement and Trace Adjustments; Track Sensor Calibration

ADJUSTMENT PROCEDURES Ccontinuea)
Arm Trace Confirmation
. Turnon the power switch of the unit.
Place a disc on the turntable and set the number of rotations
to 45r.p.m.
. Confirm that the tonearm correctly traces from the beginning
to the final silent groove.
If not, cut off R93 (3.3kQ) on the Contro! P.C.Board and
perform the re-confirmation. (Fig. 8)
Arm Feed Photointerrupter Position Adjustment
. Turnon the power switch of the unit.
Place a disc with little eccentricity on the turntable and play
it back.
. After the disc has been rotated 3 or 4 times, push the
CUEING button to elevate the tonearm.
. At this time, adjust the arm feed screw through the right hole
on the cabinet with a screwdriver, so that the tonearm is
elevated straight up. (Fig. 5)
Arm Feed Screw
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Fig. 5
Track Sensor Sensitivity Adjustment
. Short-circuit between TP1 (GND) and TP4. (When the
tonearm is placed on the turntable, the turntable does not
rotate.)
. Connect the DC VTVM’s between TP2 and GND and
between TP3 and GND. (Fig. 7)
Place the standard reflective plate on the center between the
turntable shaft and turntable edges.
4. Turnon the power switch of the unit.
Move the tonearm to the place above the standard reflective
plate. Lower the tonearm on the plate with the CUEING
button.
6. Adjust VR11, so that the voltage of TP3 becomes 3.5V.
. Elevate the tonearm with the CUEING button. At this time,
adjust VR12, so that the voltage of TP2 becomes 3.8V.
Note:
If the proper sensitivity is not obtained, cut off R105 and
perform the re-adjustment.
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Fig. 6
Leadin Adjustment
Turn on the power switch of the unit.
Place a disc on the turntable and push the START button.
Adjust VRO1 through the hole on the cabinet bottom, so that
the tonearm is correctly led into the disc. (Fig. 7)
Approach Adjustment
Turn on the power switch of the unit.
Keep the approach knob in the center click position.
Selecxt the 2nd ~ 6th programs and adjust VRO2, so that
the last portion of the previous program is not reproduced or
music is not reproduced on its way. (Fig. 7)
VRO1 for Leadin Adjustment
VRO2 for ApproachAdjustment
Fig. 7