Zenith ZDX-313, Service Manual

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PROTECTION, MAINTENANCE AND CHECK OF VIDEO FUNCTION
4-20
2. Essential Check and Repair
Recording density of the video is far higher than the audio.
Therefore video parts are very precise so as to allow only
error of 1/1000mm or so in order to maintain compatibility
with other videos.
If one of these parts is polluted or old, same phenomena will
appear as they are damaged.
To maintain clear screen, regular check, replacement of old
and damaged parts and oil supply, etc are essential.
3. Regular Check and Repair
Check and repair schedule is not constant since they vary
depending on method that the consumer uses video and
environment where the video is installed at.
However, for the video used by common household, good
screen will be maintained if regular check and repair per
1,000 hour is performed. The following chart shows relation-
ship between using time and checking time:
4. Tools for Check and Repair
(1) Grease: Floil G-3114 (KANTO) or equivalent grease
(Green)
(2) Grease: Kanto G-754, PL-433 (Yellow)
(3) Alcohol (Isopropyl Alcohol)
(4) Cleaning Patch (cloth)
5. Maintenance Process
5-1) Removal of Foreign Material
(1) Removal of foreign material from video head (Fig. C-9-4)
Firstly try to use a cleaning tape.
(1) Use a cleaning patch if foreign materials are not removed
with the cleaning tape due to severe dirty of the head.
Soak the cleaning patch in alcohol and put it to the head
tip. Smoothly turn the drum (turning cylinder) to the right
or left (In this case, the cleaning patch must not be
moved vertically).
(1) After completely drying the head, test the traveling status
of the tape.
(1) If alcohol (Isopropyl Alcohol) remains at the video head,
the tape may be damaged when this solution touches
with the head surface.
Never use a cloth bar (commercial sale)
(2) Wipe the tape transport system and the drive system
with the cleaning patch soaked in alcohol (Isopropyl
Alcohol) when removing foreign materials from them.
1) The part touched with the traveling tape is called as
tape transport system. The drive system consists of
parts to travel the tape.
(2) 2) Care must be exercised so that unreasonable force
to change the pattern will be applied to the tape trans-
port system during removal of foreign materials.
About
1 year
One hour
Table 1
Two hours
Three hours
Time
Requiring
Checking
Average
hours used
per day
About
18 months
About
3 years
Fig. C-9-4
Drum
(Turning Cylinder)
Head Tip
Soak alcohol
(Isopropyl Alcohol).
Cleaning Patch
(Cloth)
Smoothly turn the drum (turning
cylinder) touching the soft surface
to the head tip surface.