ADJUSTMENT OF QUARTZ CONTROLLED FREQUENCY
A Method
The free running frequency of the oscillator is adjusted by means of
a capacitive trimmer
connected in series with the quartz.
The oscillator is free running when pin
1
of SAA 5030 circuit is
directly connected to
V (jumper between
and
and pin 7 is
connected to
V via a 5.6 M Ohm resistance (jumper between TP3 and
TP4).
Video signal
on oscillator is compared against sand-castle
pulse present on Pin 5 of SAA 5030 (TP 7).
Capacitive trimmer is adjusted so as to maintain ratio between the
two signals unchanged (i.e. find the position in which relative shift
between the two waves is less emphasized).
Remove again shortcircuiting jumper and 5.6 M Ohm resistance.
Oscillator free running frequency is encreased by means of this
resistance from approx. 0.5
to over 6 MHz, this assuring that
signal quality detector provided in circuit SAA 5030 operates in the
best manner.
B Method
For capacitive trimmer adjustment it is also possible to use the same
teletext reproduction.
Once again it is necessary to connect the short circuiting jumper and
the 5.6 MHz resistance as described above.
By means of remote control the teletext decoder is switched to mixer
operation.
Page memory does not necessarily have to be occupied with a teletext
page, but it is possible to use randomly selected characters
contained in memory which are sufficient for adjustment by means of
reproduction on the
screen.
Capacitive trimmer is adjusted so that characters occupy a fixed
position on the screen.
Remove once again the shortcircuiting jumper and the 5.6 MHz
resistance.
If, by means of capacitive trimmer adjustment, characters do not
reach a condition of rest, it is sufficient to adjust for minimum
character shift.
Содержание 22ZT907
Страница 1: ...TIP ZANUSSI ZANUSSI Model Chassis 22ZT907 BS 400 2 CHASSIS ZANUSSI SERVICE MANUAL ...
Страница 6: ...Rear sockets 27 Auxiliary speaker jack 28 Aerial socket 29 Clock battery recess 3 ...
Страница 38: ...j I I i i j I i j I i i j I i i j I i i i i r i 1 I j I i i i i i i i i i i i 1 6 ...
Страница 39: ...Teletext printboard ___ _ _ _____ _ _ _ _ _ __ _ I r I I I I I I I I I 1 I I _ ...
Страница 40: ...__ ___ _ _ I _ ...
Страница 41: ...BS 489 0 ...
Страница 42: ......
Страница 43: ... I _ r i I 1 I _ _L 12 _L 7 e_ L I illI 46 439 000 2 3 1 5 6 7 8 9 1 0 1 1 1 2 82 W ...
Страница 44: ......
Страница 45: ......
Страница 46: ......
Страница 47: ......
Страница 48: ......
Страница 49: ......
Страница 50: ......
Страница 51: ......
Страница 52: ......
Страница 53: ......
Страница 54: ......
Страница 55: ......
Страница 56: ......
Страница 57: ......
Страница 58: ......
Страница 59: ......
Страница 60: ......
Страница 61: ......
Страница 62: ......
Страница 63: ......
Страница 64: ......