Adjustment Procedure - NEC MultiSync 2A Service Manual

A DJUSTMENT PROCE DURE
Standard Adjustment Conditions
1) Power source voltage: AC120V 60 Hz
2) Aging; Adjust after leaving power on for 20 minutes or more.
3) Signals:
Video: VGA, 800X600 mode, 0.7Vp-p 750 terminal, positive polarity
II
MAC mode Video:
Synchronizing: VGA, 800X600 mode TTL level positive polarity/negative polarity
Deflection frequency: H. 31.5kHz/35kHz
Unless otherwise specified, use signal 1 (VGA 350 line mode).
NOTE: Adjust the signal level to the threshold with the display input section of a signal cable from
the signal generator terminated with standard resistance 750.
1.
SW. REG. UNIT
1) +B,, (VR651) +110V LINE
Insert the connector terminals CN-D6 and CN-D7 as shown in Figure 1, and adjust the power supply
alone. After adjustment, insert the short connector as shown in Figure 2 to connect the power supply
to the monitor set.
Adjust VR651 to be 110 DC
This control is permanently sealed at factory.
Do not attempt to readjust.
NOTE: Do not operate the SW. REG. unit itself without any load.
Figure 1
+110V +24V
w� � : � :
GND
GND
2.
Pre-adjustment of SUB PWB
1) F/V converter adjustment
Input fH=31.5kHz horizontal sync. positive polarity 12Vp-p between CN-S2 pin 3 and GND.
Adjust VR551 so that 7.90 ±0.05V DC is obtained between TP502 and GND.
High voltage protector setting
2)
With 38.9 ±0.1V DC applied between TP2001A and GND, adjust VR2001 to obtain 0.2 ±0.05V DC
between TP2001C and GND.
Due to DHHS, after adjusting VR2001 seal with an adhesive (TE-385RTV) and cap (74004891 )
0.7Vp-p
sync.: 0.3Vp-p (750 terminal)
Separate
V. 56Hz/60Hz/66Hz/70Hz
- 12-
Figure 2
.