Construction; Crt; Power Supply Circuit; Deflection Circuit - NEC MultiSync 3D JC-1404HME Service Manual

1. CONSTRUCTION
Multisync 3D consists of six major modules:
(1-1) CRT
(1-2) Power supply module
(1-3) Deflection module
(1-4) Interface module
(1-5) Video module
(1-6) Digital control module
(1-1) CRT
The CRT is a Vacuum Tube which generates focus beams of electrons that are deflected by the
deflection yoke. These beams contact with the phosphor surface of the CRT produce light.
The fluorescent surface of the CRT has three different colors of phosphors. An electron gun which
consist of the metal coil heater, a cathode, and five grids all mounted in line (on the same horizontal
axis) on the same shaft. The three beams (Red, Green, and Blue) of the electron gun pass thru the
shadow mask before stricking the phosphorus surface of the CRT. The shadow mask ensures that
the beams will stricke only their corresponding phosphor colors on the screen.
A combination of Red, Green, and Blue phosphor dots stricked with the correct amplitude can
produce any color.
(1-2) Power Supply Circuit
Many different D.C. power supply voltages are produced in the MS-3D.
The following is listing of them:
a) +170V
b) +85V
c) +24V
d) Variable main DC/DC converter output (+Bline for H.OUT module)
e) +18V
f) +12V
g)
+6V
h) +5V
i)
-12V
j) -30V
Voltages a) thru c) are supplied by the Switching Regulator Unit (PWE-253A) and Voltages d) thru
j) are generated on the MAIN PWB (PWE-248A) by using Voltages a) and c) line power as the
source.
(1-3)
Deflection Circuit
Consists of the following three circuits:
a) Horizontal deflection
b) Vertical deflection
c) High voltage circuit for the CRT (Flyback Trans)
-44-