Mitsubishi Electric 1786FD2 Service Manual page 61

MEA 1786FD2 CRT Monitor Service Guide
3.5 Control circuit
1N4004
R613
36K
C615
2200P
50V
(PE)
R612
47
The current mode control IC UC3842 is used in the switching power supply which function of each
pin
described as follows.
pin 1 : Error amplifier output
pin 2 : Error amplifier reverse input
pin 3 : Current sense
pin 4 : OSC sawtooth
R614
D611
100K
1N4148
D612
1N4148
C617
+
4.7U
50V
(EL)
C616
0.01U
100V M603
(PE)
ZD603
5.1V
M604
C625
(OPEN)
7
8
VREF VCC
IC601
UC3842
4
R/C
COMP FB
1 2
C619
MCR100-3
0.022U
A
50V
C618
(D)
0.01U
50V
R615
K
(D)
51K
R616
10K
pin 5 : Ground
pin 6 : Output
pin 7 : VCC
pin 8 : Reference Voltage:5V
Circuit Operation Theory
6
OUT
3
ISSEN
GND
5
ZD602
IC603
24V
R622
510
G
C627
+
R620
10U
10K 50V
(EL)
+6.5VA
R738
82
1/2W
4 1
R607
0.15
2W
R611
1K
*
*
C620
820P
50V
(D)
1 5