NEC MultiSync 4FGe Service Manual page 20

(2-l) MAIN PWB ADJUSTMENT
Horizontal Hold
(1)
Receive signal lO(all "H").
(a)
Adjust VR852(5.14V
(b)
GND on Adjustment jig (TP-A @I and 0) is OV ±O.O5V.
(c)
Short SW46 on Adjusting jig (TP-A @ and @> and adjust VR501
(H HOLD 1) so that there is one screen.
Open SW46 on Adjusting jig (TP-A @ and 0) and check for
(d)
synchronization.
Receive signal lO(all "H").
Short SW46 on Adjustment jig (TP-A @I and 0) and adjust VR502
(H HOLD 2) so that there one screen.
Open SW46 on Adjustment jig (TP-A @I and 0) and check for
(g)
synchronization.
Horizontal Raster Centering
(2)
(a) Receive an all-black signal.
(b) If necessary, adjust the brightness control so that the raster is
faintly illuminated.
(c) If necessary, press the user control switch(SW101) and compress
the amplitude until both edges of the horizontal raster can be
seen. (Adjust the HORIZONTAL RASTEP size about 27Omm)
(d) Adjust VR552 so that the raster is within the following limits
space between bezel and raster right and left space difference
± 2 m m .
Vertical Linearity
(3)
Perform this procedure only necessary.If needed:
(a) Receive a crosshatch pattern.
(b) Adjust VR401(V SUB HEIGHT) so that the vertical screen size is
approximately 195mm.
(c) Adjust VR402(V LIN) to obtain the best vertical linearity.
Vertical Sub Height
(4)
(a) Receive a crosshatch pattern.
(b) Adjust the user control V POS switches(SW107/108)
vertical screen position.
(c) Use the V SIZE switches(SW105/106)
screen size to the maximum size.
(d) Adjust VR401(V SUB HEIGHT) so that the top and bottom horizontal
lines of the crosshatch pattern just meet the front bezel.
Side Pin
(5)
(a) Turn the VR431 mechanical center.
(b) Receive a crosshatch pattern (with outside border).
(c) Adjust the user control switches (SW101,102,105,and
the following picture size.
Vertical:
Horizontal:
(d) Short SW43 on Adjustment j ig.(TP-A @ and @>
(e) Push MEMORY RECALL SWITCH(SW109)
(f) Release the short.
(g) Adjust VR403 so that the vertical lines at left and right edges
of the screen are straight.
Signal 1
Signal 10 (1024X768(76))
ADJ) so that the voltage across TP43 and
Signal 12 (1024X768(76))
Signal 6 (800x600(56))
Signal 1 (VGA350)
to increase the vertical
Signal 6 (800x600(56))
approx. 1 9 5 m m
approx. 2 6 0 m m
for at least 2 seconds.
19
(VGA350)
to center the
106) to obtain