Primary Circuit - Tatung OMNISCAN SERIES Service Manual

(The power of the LED is fed from. P5050f the micro
board PW8-1697-2. Please Refer to circuit diagram'
Fig-38)
Analog circuit supply lines of 175V, 74V, 24V are
supplied by the secondary winding of T801 (pins 4, 3,
2 of P802 respectively).
(Refer to circuit diagram Fig-1)
175V/O.3A
74V/O.2A
24V/1A
(approximately)
(approximately)
(approximately)
3.2 PRIMARY CIRCUIT
(Refer to circuit diagram Fig-2)
Mains electricity is filtered by line choke L801 and
rectified by bridge 0801. The rectified high tension
(HT.) line is smoothed by storage capacitor C805-
C806.
Suppressors R850, R851 , R860 and R861 are
designed to protect the circuit from the effects of
SMPS PRIMARY CIRCUIT
G828~5
0.6BU
7
250V
r--,
RBO".!I
!4QN. !
270'
¥(
_ _ _ _ .J
SMPS $EQONDARY CIRPUIT
RB35 CBI9
2.SK 100PF
7W
TBOI
10
LB04
RB30
220K
CB24
47U
100V
WK'190
RB32
56K
~--~--~'~r---r--+~
13
CS26
1000U
35V
RB34
12K
Fig-1
P802
10
PWB·1640
P406
destructive voltage transients. When subjected to
high energy transient currents their impedance rapidly
changes from a high standby value . to a low
conducting value to keep voltages within safe limits.
Switch S802 is used to select 11 OV or 220V line input.
(110V-SHORT; 220V-OPEN).
S801 is the power switch of the line input.
R80S GSOl
0.5 0.0056U
2W
630V
R811
47K
0805
RGPIOM
1801
Fig-2
n~·4r---+------~-;--r+~nuL-4~---<·~
LBOI FBOI
r - -
1 T2.5A
R804
250V
180M! I RB03
290 L _
~
J
220
DEGAUSSING
SW .
..
P.03~
5901
ESB- ....
ESB99877V:-
POWER SW.
L811
TNF-OOI
L901
DEGAUSSING
GOIL
=
3-2
=