Check And Adjustment Of Fm Envelope; Guide Roller Adjustment Check; Height Adjustment Of; Guide Roller (Sp) - Mitsubishi hs-u778 Service Manual

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. Confirm that the FM Waveform is flat such as in (A).
4. Perform the Item 3-2-2. "Height Adjustment of GUIDE
ROLLER (SP) " if the leading edge (the DRUM entry
side) of the FM Waveform is not flat (Waveform (B) or
(C)). Perform the Item 3-2-3. "Height Adjustment of
GUIDE ROLLER (TU)" if the trailing edge (the DRUM
exit side) is not flat (Waveform (D) or (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) will rotate smoothly.
2. Observe the leading edge (DRUM entry side) of the
FM Waveform. If it looks like (B), the GUIDE ROLLER
may be set too low. If it looks like (C), the GUIDE
ROLLER may be set too high. To adjust it, turn the
height adjustment screw at the top of the GUIDE
ROLLER (SP) so that the FM Waveform becomes flat
such as in (A).
• 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 the Item 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) will rotate smoothly.
2. Observe the trailing edge (DRUM exit side) of the FM
Waveform. If it looks like (D), the GUIDE ROLLER
may be set too low. If it looks like (E), the GUIDE
ROLLER may be set too high. To adjust it, turn the
height adjustment screw at the top of the GUIDE
ROLLER (TU) so that the FM Waveform becomes flat
as in (A).
• 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 the Item 3-2-4. "Coarse Adjustment of
Phase".
(A)
(B)
(C)
(D)
(E)
GUIDE ROLLER
Height Adjustment Driver
GUIDE
ROLLER
(SP)
- 31 -
Fig. 3-2-1
(859C259O80)
GUIDE
ROLLER
(TU)
Fig. 3-2-2