Fisher MT-250 - Page 8

CABINET & CHASSIS PARTS LIST (continued)
pet Part No. Description Q'ty
71 141-0-1939-17560 Sensor P.C.B. Assy 1
72 141-0-1939-17450 LED P.C.B. Assy 1
73 141-0-1939-17550 Primary P.C:B. Assy 1
74 141-0-1939-17430 Control P.C.B. Assy 1
75 141-0-1939-17440 Power Switch P.C.B. Assy 1
81 106-3-1304-00011 Hex. Nut-3, M4.0 1
82 110-3-2104-00011 Spring Washer-2, M4.0 1
83 143-3-1703-00811 Screw, Bind Hd. Tapping-B, +M3.0x8 2
NOTES:
1. Parts order must contain Model Number, Part Number and
Description.
2. Ordering quantity of screws and resistors must be multiple of
10 pes.
-7-
PRODUCT SAFETY NOTICE
Each precaution in this manual should be followed
during servicing. Components identified with the IEC
symbol A\ in the parts list and the schematic diagram
designate components in which safety can be of special
significance. When replacing a component identified
with A\, use only the replacement parts designated, or
parts with the same ratings of resistance, wattage or
voltage that are designated in the parts list in this manual.
Leakage-current or resistance measurements must be
made to determine that exposed parts are acceptably
insulated from the supply circuit before returning the
product to the customer.
TURNTABLE ADJUSTMENT
BEFORE ATTEMPTING ADJUSTMENT 3.
1. Adjustments through the rear of the cabinet should be
carried out from the bottom with the cabinet placed firmly on
a level base.
2. Carry out adjustment procedures in the order given here.
MEASURING INSTRUMENTS REQUIRED
e@ Stroboscope Sheet
@ DCVTVM (DC voltmeter with high impedance) 1.
e Screw driver
STYLUS
HEIGHT
ADJUSTMENT
2.
1. Remove the turntable mat and belt and turn the power on.
2. Press the <j button and move the tone arm so that the stylus
' height adjustment screw can be seen in the turntable
aperture (see Fig.1).
3. Turn the adjustment screw so that the stylus height is
7.5mm from the turntable (it is best to use some instrument
like that depicted in Fig.2). 5.
Set the SPEED switch to 33 rpm and carry out the same
procedure with VR3.
NOTE:
Always carry out this adjustment by adjusting the 45 rpm
speed first.
ARM FEED PHOTOINTERRUPTER SENSITIVITY
ADJUSTMENT
Pless the <] button and move the tone arm so that the VR1
on the Sensor PCB can be seen in the turntable aperture.
Then fully turn the VR1 counter-clockwise.
Place a minimally de-centered record disk on the turntable
and playback.
When the turntable has completed at least 5 revolutions
after the needle has dropped on to the recoad, pless the
CUEING button and lift the tone arm.
At this point, adjust VR1 on the Control PCB so that the arm
rises straight up (see Fig.4).
If the adjusting range of VR1 is limited and it is hard to
adjust, turn the VR1 on the Sensor PCB clockwise a little
and adjust again.
FRONT
(Bottom View)
Stylus Height
Adjustment Screw ®
Arm Feed
Adjustment Volume (VR1 =e
Fig.1 °
=)
Cartridge Prepare a piece of Fig.4
7.5mm section paper or a film
Turntable LEAD-IN ADJUSTMENT
1. Place a record on the turntable and press the PLAY/STOP
button to begin lead-in.
Fig.2 2. Turn the adjustment cam so that lead-in attains the proper
position (see Fig.5). (Rotating the cam clockwise moves the
ROTATION ADJUSTMENT lead-in in toward the center, while rotating it counter-
1. Replace the belt and turntable mat and set the SPEED
switch to 45 rpm.
2. Using a stroboscope sheet, adjust VR2 on the Control PCB
so that the rotation matches up (see Fig.3).
FRONT
(Bottom View)
;
Rotation Adjustment
Volume, 33rpm (VR8)
Rotation Adjustment
Volume,
45rpm
(VR2)
‘NY
e
Fig.3
clockwise moves it out towards the edge.)
Lead-in Position
Adjustment Cam
(Bottom View)
REAR
Fig.5