Mitsubishi Electric HS-U449 Service Manual page 43

3-2. Check and Adjustment
of the FM Envelope
3-2-1. GUIDE ROLLER Adjustment Check
1. Play back an alignment tape (NM6KE2 : 859C339O90).
2. Preset the tracking.
3. Make sure that the FM waveform is flat as shown by
Waveform (A).
4. Perform "3-2-2. Height Adjustment of GUIDE ROLLER
(SP)" if the leading edge (the DRUM entry side) of the
FM waveform is not flat as shown by Waveform (B)
and (C). Perform "3-2-3. Height Adjustment of GUIDE
ROLLER (TU)" if the trailing edge (the DRUM exit
side) is not flat as shown by Waveform (D) and (E)
3-2-2. Height Adjustment of GUIDE ROLLER (SP)
1. Loosen the height adjustment screw at the top of the
GUIDE ROLLER (SP) so that the GUIDE ROLLER
(SP) rotates smoothly.
2. Check the leading edge (DRUM entry side) of the FM
waveform. If it looks like Waveform (B), the GUIDE
ROLLER may be positioned too low. If it looks like
Waveform (C), the GUIDE ROLLER may be
positioned too high. To make the FM waveform flat as
shown by Waveform (A), turn the height adjustment
screw at the top of the GUIDE ROLLER (SP).
• Turn the screw counter-clockwise if the position of
the GUIDE ROLLER is lower than specified.
• Turn the screw clockwise if the position of the
GUIDE ROLLER is higher than specified.
3. Perform "3-2-4. Coarse Adjustment of Phase."
3-2-3. Height Adjustment of GUIDE ROLLER (TU)
1. Loosen the height adjustment screw at the top of the
GUIDE ROLLER (TU) so that the GUIDE ROLLER
(TU) rotates smoothly.
2. Check the trailing edge (DRUM exit side) of the FM
waveform. If it looks like Waveform (D), the GUIDE
ROLLER may be positioned too low. If it looks like
Waveform (E), the GUIDE ROLLER may be
positioned too high. To make the FM waveform flat as
shown by Waveform (A), turn the height adjustment
screw at the top of the GUIDE ROLLER (TU)
• Turn the screw counter-clockwise if the position of
the GUIDE ROLLER is too low.
• Turn the screw clockwise if the position of the
GUIDE ROLLER is too high.
3. Perform "3-2-4. Coarse Adjustment of Phase."
(A)
(B)
(C)
(D)
(E)
Height Adjustment Driver
GUIDE
ROLLER
(SP)
- 30 -
Fig. 3-2-1
GUIDE ROLLER
(859C259O80)
GUIDE
ROLLER
(TU)
Fig. 3-2-2