NEC MultiSync 4FGe Service Manual page 18

ADJUSTSMENT PROCEDURE
Standard Adjustment Conditions
1) Power source voltage:JC-1531VMA-2
2) Aging :Ad_iust after leaving
3) Signal:
Video
Synchronizing
Deflection
P r e - A d j u s t m e n t
1.
NOTE: The following 5 steps are to be performed only when
replaced.
VR Settings
1)
VR501 H HOLD 1 :
VR502 H HOLD 2 :
VR503 H
VR431 PARALLEL0 ADJ: Mechanical center
Heater Voltage Adjustment
2)
a) Receive character "H".
b) Supply 24V to the MAIN PWB.
c) Adjust VR551 so that the voltage across HC @ and @ is 6.1V ±O.O5V.
H V Adjustment
3)
a)
Connect CNP-HV
Turn VR505(H V ADJ VR) fully counterclockwise.
b)
c)
Receive crosshatched pattern and adjust VR501(H HOLD 1) and VR502
(H HOLD 2) to sychronize
Brightness control:
d)
Contrast control :
e)
Receive an all-black signal.
f)
Confirm that the CRT is at cut-off.
Adjust VR505 so that high voltage is 24kV ±O.lkV.
g)
Seal VR505 by using a cap(74102801) and silicon glue.
h)
Reference Voltage Adjustmant
4)
a) Supply 24V to the MAIN PWB.
b) Adjust VR851(0.96V
Adjustment-PWB (TP-B @ and @I> 0.96V ±O.OlV.
OV Adjust
5)
a) Receive signal lO(all "H").
b) Adjust VR852(5.14
±0.05V.
B-2(EE) AC220V50
power on for a minimum twenty minutes.
Analog 0.7Vp-p 75Q terminal positive polarity
Analog sync
:
TTL level Negative/positive polarity
Separate/composite
H 27kHz~62kHz
frequency
:
V 55Hz~90Hz
o f
Fully clockwise
Fully clockwise
SIZE Fully counterclockwise
:
the screen.
Fully counterclockwise
Fully counterclockwise
ADJ) so that the voltage across TP42 and GND on
ADJ) so that the voltage across TP-A @I and @ is OV
See page
AC120V6OHz/JC-1531VMB-2,R-~,
on green
Video
Synchronizing
M A I N P W B
Signal 9 (1024X768(70))
Signal 11 (42.5kHz)
Signal 10
17
,
26 for j i g
: 0.7Vp-p
: 0. 3Vp-p
the MAIN PWB is