Grundig GV 900 SV/1 Manuel De Service page 90

Drive Mechanism
3. Disassembly Instructions
3.1 Cassette Compartment
Disassembly:
– Undo 2 screws Pos. 605 (Fig. 3).
– Push the cassette compartment in the direction of the arrow (Fig. 3)
and remove it.
Fig. 3
Assembly:
– When the drive mechanism can be operated via the chassis board:
– Disconnect the video recorder from the mains.
– Short-circuit the test points P801 on the chassis board (or cover
the sensor diodes for start-of-tape and end-of-tape identification).
– Connect the video recorder to the mains.
– Press button N. The cassette mechanism is automatically set to
the cassette mounting position.
– Disconnect the video recorder from the mains.
– When the drive mechanism can´t be operated via the chassis board:
Turn the loading motor driver (Pos. 47) with a screwdriver and
position the cassette compartment gear (Pos. 38) as shown in Fig. 4.
– Insert the cassette compartment so that the teeth of the toothed rack
(Pos. 316) engage with the cassette compartment gear (Pos. 38) as
shown in Fig. 5.
38
thread
unthread
47
Fig. 4
3.1.1 Operating the drive mechanism w/o cassette compartment
– Disconnect the video recorder from the mains.
– Short-circuit the test points P801 on the chassis board.
– Reconnect the video recorder to the mains and press button A (the
threading roller units are moved to the position where it is possible
to insert a cassette).
Note: When the test points P801 are short-circuited, the drive
mechanism can be operated without a cassette being loaded.
– Open the cassette lid and fix it with an adhesive tape.
– Insert the cassette into the drive mechanism and put a weight of
about 500g on it.
– The drive mechanism can be tested in this way.
Note: Do not take out the cassette unless the video recorder is in
Standby mode.
3.2 A/C Head
– Undo 2 screws (Pos. 221 / 222, Fig. 6) and remove the A/C head
assembly.
– Unsolder the A/C head from the connecting board.
Note on re-assembling the head
– When replacing the A/C head, adjust the head horizontally at
10.8mm using the height adjustment screw (Pos. 201), azimuth
adjustment screw (Pos. 221) and the tilt adjustment screw (Pos.
220) (Fig. 6/7).
– Adjust the A/C head precisely to 0.3mm with the height adjustment
screw (Pos. 201) in Playback mode as shown in Fig. 8.
On replacement of the A/C head, carry out all adjustments described
under point 5.8 and 5.9.
5 - 10
605
38
316
Fig. 5
222
220
221
59
202
201
202
Fig. 6
3.3 Capstan Motor
– Remove the reel belt (Pos. 34) (Fig. 9).
– Undo 3 screws (Pos. 203) (Fig. 9).
– Take the capstan motor (Pos. 61, Fig. 9) out of the drive mechanism.
In doing so, the capstan shaft must not come into contact with the
drive mechanism.
Reassemble the motor in reverse order.
Make sure that the capstan shaft is free of grease.
203
61
34
Fig. 9
3.4 Headwheel Motor
– Unplug the connector of the headwheel motor to the chassis board.
– Undo 2 screws (Pos. 66a, Fig. 10) and remove the stator.
– Undo 2 screws (Pos. 66b, Fig. 10) and remove the rotor.
Notes on reassembling:
When refitting the rotor the recess in the headwheel must be visible
through hole A of the rotor (Fig. 11).
Reassemble in reverse order.
Fig. 11
3.5 Tape Drum Assembly
– Remove the headwheel motor (point 3.4).
– Remove the earth spring (Pos. 65) of the headwheel (Fig. 11).
– Unhook the spring of the head cleaning roller (Pos. 26).
– Remove the locking washer (Pos. 216) and remove the tape
transport stabilizing roller (Pos. A, option).
Note on reassembling: Put on the spring of the tape transport
stabilizing roller (Fig. 12) and position the roller so that the spring
(Pos. 13) can be tensioned. In level position with the upper edge of
the shaft, turn the tape transport stabilizing roller towards the
headwheel and press it down. Attach the locking washer.
GV 900..., GV 940...
59
Fig. 7 Fig. 8
66a
62 (Stator)
66b
66b
62
(Rotor)
65
207
207
218
218
Fig. 10
65
A
GRUNDIG Service