Grundig GDR 6460 VCR, Руководство по обслуживанию

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GRUNDIG Service GDR 6460 VCR
Fig. 4 Fig. 5
6. Adjusting the Tape Tension
– Play the torque cassette and note the value.
– The torque of the left reel should be in area 3,5…5,2mNm
(35…52g-cm).
– For adjustment eject torque cassette, change the hook-on position
of the tension spring
#
(Fig. 5) and check again.
7. Adjusting the Tape Path
– Connect the 10:1 test probes of the dual-channel oscilloscope
(triggering channel A) as follows:
• Channel A: head switching pulse – connector contact P502-3
• Channel B: FM envelope – connector contact P502-4
7.1 Coarse adjustment
– Play the test cassette.
– Adjust the reverse rollers
1
/
2
(Fig. 1) so that the FM packages
at the tape lead-in and lead-out side do not exceed the limit value
b / a
≥
0.75 (Fig. 6).
Fig. 6
a b
b/a
≥
0.75
7.2 Fine adjustment
– Set the X-value (point 4).
– Play the test cassette.
– Set the tracking position manually so that noise just starts to appear
in the picture.
– Set the reverse rollers
1
/
2
(Fig. 1) so that the amplitude of the FM
packages is as flat as possible.
– Tape riding over the upper edge:
turn the left reverse roller
1
(Fig. 1) clockwise
turn the right reverse roller
2
(Fig. 1) clock-
wise
– Tape riding over the lower edge:
turn the left reverse roller
1
(Fig. 1) counter-
clockwise
turn the right reverse roller
2
(Fig. 1) coun-
terclockwise
7.3 Check
– Play the test cassette
– Press the "picture search reverse" button followed by the "play"
button after 15 seconds. After another 3 seconds the FM packages
must recover their maximum amplitude and flat envelope. If neces-
sary, re-adjust the reverse rollers
1
/
2
(Fig. 1).
– Check the tilt of the A/C head (point 2).
– Check the height and azimuth of the A/C head (point 3).
– Check the X-value (point 4).
8. Head Position Indicator
– Play the test cassette.
– Feed in a DC voltage 2V (external supply) at P502-5.
– Press button "REC" at the remote control. The picture jitters for a
short time during the automatical adjustment.
VCR Drive Mechnism Adjustments
1. Reverse Rollers of the Threading Roller Units
– Play a E120 cassette.
– Re-adjust the reverse rollers
1
/
2
(Fig. 1) if necessary so that the
tape does not touch the top or bottom edge of the rollers.
1
2
3
Fig. 1
2. Tilt of the A/C Head
– Play a E120 cassette.
– Adjust the tilt of the A/C head with screw
4
(Fig. 3) so that the tape
passes the tape guide pin
3
(Fig. 1 / 2) in the middle between the
top and bottom edge.
TAPE
4
5
6
7
8
Fig. 2 Fig. 3
3. Height and Azimuth of the A/C Head
– Connect the oscilloscope to chinch output "AUDIO OUT L/R".
– Play the test cassette with the 6kHz Standard Sound audio signal
recording.
– Set the height adjustment screw (
5
, Fig. 3) for maximum output
voltage.
– Set the azimuth adjustment screw (
6
, Fig. 3) for maximum output
voltage.
4. X-Value
– Connect oscilloscope with 10:1 test probe to connector contact
P502-4.
– Play the test cassette.
– Press tracking button "–" (1) min. 15 seconds. Afterwards press
button "+" (3) for tracking step by step 24 times (middle position of
tracking).
– Coarse adjustment:
Put a crosstip screwdriver (Ø 4.5mm) in hole
7
(Fig. 3). Loosen
screw
8
. Adjust A/C head with the crosstip screwdriver in mechani-
cal mid-position (screw driver as vertical as possible) for maximum
FM packages. Tighten screw
8
.
– Fine adjustment:
Press tracking button "–" (1) min. 15 seconds (tracking minimum).
Note the value of FM packages.
Press tracking button "+" (3) min. 15 seconds (tracking maximum).
Select the tracking position with the higher FM packages with
tracking buttons "–" (1) / "+" (3).
Put a crosstip screwdriver (Ø 4.5mm) in hole
7
(Fig. 3). Loosen
screw
8
. Adjust A/C head with the crosstip screwdriver for equal
FM package level. Tighten screw
8
.
Check level of FM packages at tracking minimum and maximum
position and if necessary adjust again (fine adjustment) .
5. Adjusting the Brake Band
– Slide 2 levers
9
(Fig. 4) and cassette compartment to inside.
– Disconnect the unit from mains at the moment when the tape tension
lever reaches the outside position (right reel is turning).
– Adjust brake band
@
(Fig. 5) so that the hole
0
of tape tension lever
is congruent to the hole
!
of the drive chassis.