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Caution:
Before removing the case, be sure to turn off the
power. Note that a high voltage ( 1 5 0 0 V max) is
present on the C R T socket and the printed circuit
board.
Keep your hand, screwdriver, etc. away
from any part carrying a high voltage after removal
of the case.
Removal of C R T Bezel
P R E S S T H E P R O J E C T I O N S O N T H E
B E Z E L
D O W N A N D T H E B E Z E L
B E
R E M O V E D .
Fig. 42 Removal of C R T bezel
A D J U S T M E N T
The oscilloscope is factory adjusted prior to ship-
ment.
If readjustment becomes necessary, the
following points should be observed.
1. Check the power supply is the correct voltage.
2. For adjustments, use a well insulated screw-
driver.
3. Before making adjustments, be sure to turn on
the power and wait until the unit is stabilized.
4. For adjustment, follow the procedures describ-
ed below.
5. If special test instruments are required for ad-
justments, contact your Trio local service sta-
tion.
Power Voltage Adjustment:
Remove the bottom shielding plate before power
voltage adjustment.
1. Adjustment of Charging Voltage
Connect a digital voltmeter to the " + " and
" — " sides of the battery connecting leads,
then adjust V R 5 0 1 on the power supply circuit
board for + 13.7V.
2. Adjustment of -f- 10V Output Voltage
Connect a digital voltmeter to the No. 3 pin of
the connector P 3 0 2 on the horizontal circuit
board and to the earth point. Adjust V R 5 0 4
on the power supply circuit board for + 10.0V.
3. Adjustment of Cut-off Voltage
4. Adjustment of indication illumination voltage
Adjustment of Trace O F F Voltage
1. Display a trace by pulling the P U L L A U T O
2. Adjust V R 4 0 5 on the trigger circuit board so
Variable D C B A L A d j u s t m e n t
Adjust V R 1 0 2 on the left side of the case (for C H 2 ,
use V R 1 0 7 on the right side) so that the trace stays
C A N
still even when the vertical attenuator V A R I A B L E
control is turned.
S T E P A T T D C B A L A d j u s t m e n t
Adjust V R 1 0 1 on the left side of the case (for C H 2 ,
use VR 106 on the right side) so that the trace stays
still even when the vertical attenuator V O L T S / D I V
control is turned.
Horizontal Positon A d j u s t m e n t
With the
center position, adjust V R 3 0 4 on the horizontal cir-
cuit board so that the trace starts at the left end of
the screen.
X Position A d j u s t m e n t
With the S W E E P T I M E / D I V switch set to X - Y posi-
tion, adjust V R 3 0 5 on the horizontal circuit board
so that the bright spot comes to the center of the
screen when the input of X axis (CH2) is grounded.
Connect an external DC power (12V) to the
battery connecting leads. Adjust V R 5 0 2 on
the power supply circuit board so that the
power lamp goes off when the voltage is
dropped from 12V to 10.0V.
Adjust V R 5 0 3 so that the POWER lamp is il-
luminated when the voltage drops from 12V to
10.8V by connecting as indicated in Item (3).
Knob.
that the trace disappears at 11 o'clock position
of the P O W E R / I N T E N knob.
POSITION knob set to its mechanical
Fig. 4 3
29
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