Replacement Of Major Parts; Before Starting Disassembling (Phase Matching Between Mechanical Parts) - JVC HR-S3800U Service Manual

2. Cleaning
Regular cleaning of the transport system parts is desirable
but practically impossible. So make it a rule to carry out clean-
ing of the tape transport system whenever the machine is
serviced.
When the video head, tape guide and/or brush get soiled,
the playback picture may appear inferior or at worst disap-
pear, resulting in possible tape damage.
(1) When cleaning the upper drum (especially the video
head), soak a piece of closely woven cloth or Kimu-wipe
with alcohol and while holding the cloth onto the upper
drum by the fingers, turn the upper drum
counterclockwise.
Note: Absolutely avoid sweeping the upper drum
vertically as this will cause damage to the
video head.
(2) To clean the parts of the tape transport system other than
the upper drum, use a piece of closely woven cloth or a
cotton swab soaked with alcohol.
(3) After cleaning, make sure that the cleaned parts are com-
pletely dry before using the video tape.
3. Lubrication
With no need for periodical lubrication, you have only to lu-
bricate new parts after replacement. If any oil or grease on
contact parts is soiled, wipe it off and newly lubricate the
parts.
(1) See the mechanism assembly and disassembly diagrams
for the lubricating or greasing spots. See Table 2-1-2 for
the types of oil or grease to be used.
Type Name
Grease Maltemp SH-P
Oil Cosmohydro HV56
Table 2-1-2 Grease and oil used for the unit
4. Suggested servicing schedule for main components
The following table indicates the suggested period for such
service measures as cleaning,lubrication and replacement.
In practice, the indicated periods will vary widely according
to environmental and usage conditions.However, the indi-
cated components should be inspected when a set is
brought for service and the maintenance work performed if
necessary. Also note that rubber parts may deform in
time,even if the set is not used.
Symbols on the dis-
Serial No.
assembly diagrams
KYODO-SH-P AA
COSMO-HV56 BB
System Parts Name
Upper drum assembly
A/C head
Lower drum assembly
Pinch roller arm assembly
Full erase head
Tension arm assembly
Capstan motor (Shaft)
Guide arm assembly
Capstan motor
Capstan brake assembly
Main brake assembly
Belt (Capstan)
Belt (Loading motor)
Loading motor
Clutch unit
Worm gear
Control plate
Brush
Tension brake assembly
Rotary encoder
¤
: Cleaning
R
: Inspection or Replacement if necessary
Table 2-1-3

2.2 REPLACEMENT OF MAJOR PARTS

2.2.1 Before Starting Disassembling (Phase matching
between mechanical parts)
The mechanism of this unit is closely linked with the rotary
encoder and system controller circuits.
Since the system controller detects the status of mechani-
cal operation in response to phases of the rotary encoder
(internal switch positions), the mechanism may not operate
properly unless such parts as the rotary encoder, control
plate, loading arm gear, control cam, cassette gear, limit gear,
relay gear and drive gear are installed in their correct posi-
tions.
Especially, this model is not provided with any cassette hous-
ing assembly, so that cassette loading and unloading must
be accomplished by operation of the cassette holder assem-
bly. The latter is in turn driven by such parts as the drive
gear, relay gear and limit gear. Exercise enough care, there-
fore, to have the phases of all this gear matching one an-
other.
(For information on phase matching of the mechanism, see
the instructions on how to install individual parts.)
Operation Hours
~1000H ~2000H
¤R R
¤R ¤R
¤ ¤R
¤ ¤
¤ ¤
¤ ¤
¤ ¤
¤ ¤
R
R
R
R R
R
R
R
R
R
¤R ¤R
R R
R
2-6