JVC HR-S10EG Service Manual page 52

2.3 MAIN ASSEMBLY REPLACEMENT
Remove the external covers, circuit boards and cassette
housing, as necessary, to allow replacement.
2.3.1 Upper Drum (See Figure 2-5.)
1. Unsolder four wires connecting the lower drum from
the relay pins of the upper drum (perform quickly to
avoid damaging the wires).
Relay Pin Color | Channel Inner/Outer |
Brown CH-1 Brown/Gray
Red CH-2 | Red/White
Table 2-4 Upper drum wiring
Upper drum
Lower drum
Fig. 2-5 Upper drum replacement
2. Take out two screws and remove the upper drum by
lifting it upwards.
3, Use alcohol to clean the lower face of new upper drum
and the upper face of the lower drum.
When handling and installing the new upper drum, avoid
directly touching the head tips and use care not to
scratch the drum,
4, Reassemble by reversing the above steps. When resolder-
ing, observe the correct channels (refer to Table 2-4) and
avoid overheating the wires.
5. Perform the upper drum eccentricity adjustment.
1) Connect an oscilloscope to TP-PB. FM (FM OUT) of
the SERVO board. Trigger the oscilloscope externally
with the signal from TP-11 (DRUM F.F.) of the
SERVO board.
2) Supply a video signal, then playback.
Fig. 2-6 Incorrect example
6. Perform the FM waveform checks and adjustments (refer
to section 2.4.6).
. Perform the P.B./REC switching point adjustments.
Refer to sections 3.5.5, 3.5.6 and 3.5.9.
N
2.3.2 Full Erase Head (See Figure 2-7.)
1. Take out the nut and remove the flanges, washers, im-
pedance roller, collar and spring.
. Disconnect connector CN2 from the OSC board.
3. Unhook the torsion spring from the F.E. head and
remove the F.E. head upwards.
4. Install a new F.E. head and reassemble the other parts
into their original positions.
5. Perform the impedance roller height/FM waveform
checks and adjustments (refer to sections 2.4.5 and
2.4.6).
N
sant
t 'Upper flange
Cx fuser
eC Impedance roller
FE head
Collar > eg
Washer i
—]
Main-deck
| Be is
Fig. 2-7 F.E. head replacement
2.3.3 Audio/Control Head (See Figure 2-8.)
1. Take out the screw and remove the shield cover.
2. Disconnect two connectors CN4 and CN5 from the
AUDIO board, disconnect connector CN3 from the
SERVO board,
3. Take out two screws and remove the A/C head.
4. Replace the A/C head and reassemble by reversing
the above steps.