Philips VR109/55 Service Manual page 55

www.freeservicemanuals.info
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. Play back a blank cassette tape and check to see
that the tape runs without creasing at Guide Roll-
ers [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.)
Note: Beneath each Guide Roller, there is a
small screw. (Refer to Fig. M5.) This screw works
Guide Roller [2]
A
Take-up Guide Post [4]
Lead Surface of Cylinder
Correct
Guide Roller
Tape
Small Screw
Take-up Guide
Post
Tape
06/28/2012
Guide Roller [3]
AC Head
B
Fig. M3
Tape
Fig. M4
Incorrect
Fig. M5
to apply adequate torque to the shaft of each
Guide Roller so that the Guide Roller turns prop-
erly. Even when adjusting the height of the Guide
Roller(s), do not touch these two small screws.
3. Check to see that the tape runs without creasing at
Take-up Guide Post [4] or without snaking be-
tween Guide Roller [3] and AC Head.
(Fig. M3 and M5)
4. If creasing or snaking is apparent, adjust the Tilt
Adj. Screw of the AC Head. (Fig. M6)
Azimuth Adj.
Screw
X-Value Adj.
Screwdriver
1-B. X Value Alignment
Purpose:
To align the Horizontal Position of the Audio/Con-
trol/Erase Head.
Symptom of Misalignment:
If the Horizontal Position of the Audio/Control/Erase
Head is not properly aligned, maximum envelope can-
not be obtained at the Neutral position of the Tracking
Control Circuit.
1. Connect the oscilloscope to TP301 (C-PB) and
TP303 (CTL) on the Main CBA. Use TP302 (RF-
SW) as a trigger.
2. Play back the Gray Scale of the Alignment Tape
(4822 397 10057) and confirm that the PB FM sig-
nal is present.
3. Set the Tracking Control Circuit to the center posi-
tion by pressing the CH UP button then the PLAY
button on the VCR. (Refer to note on bottom of
page 2-3-4.)
4. Use the X-Value Adj. Screwdriver so that the PB FM
signal at TP301 (C-PB) is maximum. (Fig. M6)
5. Press CH UP button on the VCR until the CTL wave-
form has shifted by approx. +2msec. Make sure
that the envelope is simply attenuated (shrinks in
height) during this process so that you will know
the envelope has been at its peak.
2-3-3
World of Free Manuals
AC Head
Tilt Adj.
Screw
Fig. M6
H67T0MA