Sharp DV-NC150U Service Manual page 95

1-A. Preliminary/Final Checking and
Alignment of Tape Path
Purpose:
To make sure that the tape path is well stabilized.
Symptom of Misalignment:
If the tape path is unstable, the tape will be damaged.
Note: Do not use an Test Tape for this procedure. If the
unit is not correctly aligned, the tape may be damaged.
1. Playback a blank cassette tape and check to see that
the tape runs without creasing at Guide Rollers [2]
and [3], and at points A and B on the lead surface.
(Refer to Fig. M3 and M4.)
2. If creasing is apparent, align the height of the guide
rollers by turning the top of Guide Rollers [2] and [3]
with a Guide Roller Adj. Screwdriver. (Refer to Fig.
M3 and M5.)
Guide Roller [2]
A
Take-up Guide Post [4]
Lead Surface of Cylinder
Correct
Guide Roller
Tape
Take-up Guide
Post
Tape
Guide Roller [3]
ACE Head
B
Fig. M3
Tape
Fig. M4
Incorrect
Fig. M5
2-3-3
3. Check to see that the tape runs without creasing at
Take-up Guide Post [4] or without snaking between
Guide Roller [3] and ACE Head. (Fig. M3 and M5)
4. If creasing or snaking is apparent, adjust the Tilt Adj.
Screw of the ACE Head. (Fig. M6)
Azimuth Adj. Screw
ACE Head
Tilt Adj. Screw
1-B. X Value Alignment
Purpose:
To obtain maximum PB FM envelope signal at the preset
position of the Tracking Control Circuit, align the Horizontal
Position of the ACE Head.
Symptom of Misalignment:
If the Horizontal Position of the ACE Head is not properly
aligned, maximum PB FM envelope cannot be obtained
at the preset position of the Tracking Control Circuit.
1. Connect the oscilloscope to TP301 (C-PB) and TP503
(CTL) on the Main CBA. Use TP504 (RF-SW) as a
trigger.
2. Playback the Gray Scale of the Test Tape
(9HSFL8NW) and confirm that the PB FM signal is
present.
3. Set the Tracking Control Circuit to the preset position
by pressing CH UP button on the remote control unit
then "PLAY" button on the unit. (Refer to note on
bottom of page 2-3-4.)
4. Use the Flat Screwdriver so that the PB FM signal at
TP301 (C-PB) is maximum. (Fig. M6)
5. To shift the CTL waveform, press CH UP or CH
DOWN button on the remote control unit. Then make
sure that the maximum output position of PB FM
envelope signal become within ±2ms from preset
position.
Flat
Screwdriver
Fig. M6
H9745MA