Philips 20MC4304, Руководство по обслуживанию

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2-3-3 MK14NMA_PC
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 Alignment 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.)
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)
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 TP (C-PB and CTL)
on the Main CBA. Use TP (RF-SW) as a trigger.
2. Playback the Gray Scale of the Alignment Tape
(VFMS0001H6) and confirm that the PB FM
signal is present.
3. Set the Tracking Control Circuit to the preset
position by pressing [CHANNEL
K
] button 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 TP (C-PB) is maximum. (Fig. M6)
Guide Roller [2]
Guide Roller [3]
A
B
Take-up Guide Post [4]
ACE Head
Fig. M3
Lead Surface of Cylinder Tape
Fig. M4
Take-up Guide
Post
Tape
Guide Roller
Tape
Correct
Incorrect
Fig. M5
Azimuth Adj. Screw
Flat
Screwdriver
Tilt Adj. Screw
ACE Head
Fig. M6