Low volts power supply <7, Line rectifier and filter, Clamp – Tektronix 1705A User Manual
Page 210: Output filters, Output uv shutdown, Pulse width modulator, Switcher mosfet, Snubber, Error, Feedback transformer driver
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J5
CAUTION:
ALL CIRCUITRY TO THE
MOUNTING
LINE RECTIFIER
AND FILTER
L4
1MH
LEFT OF THE ISOLATION
BOUNDARY IS AT POWER LINE
POTENTIAL AND REQUIRES
AN ISOLATION TRANSFORMER
TO SERVICE
BOUNDARY
ISOLATION
CLAMP
C63
NOT INSTALLED
C62
NOT INSTALLED
OUTPUT FILTERS
L3
4.7UH
CR10
1700F10
(DC OPER.)
UPGRADE
ONLY
USED WITH
C36
560UF
C38
560UF
W3
0 OHM
W4
0 OHM
+15A
+15V
+40V
--- 15A
--- 15V
C30
560UF
C29
560UF
L2
4.7UH
R67
10.0
CR12
CR11
RV1
NOT INSTALLED
CR18
NOT INSTALLED
10
8
14
13
12
11
9
2
1
5
6
7
T3
CR14
C44
.47UF
R93
150K
R94
150K
R91
100K
R92
100K
R102
8
DS4
C54
330UF
CR23
CR22
CR21
CR24
90--- 250V
C56
.022UF
F1
2A
C57
.068UF
R89
5
J10
REAR
PANEL
J6
OUTPUT UV
SHUTDOWN
5
6
7
U3B
LM393
R97
2.00K
+5VC
C47
.47UF
CR19
CR25
PULSE
WIDTH
MODULATOR
COMP
1
VFB
2
ISEN
3
RT/CT
4
REF
8
VCC
7
OUT
6
GND
5
U5
UC3842
+5VC
SWITCHER
MOSFET
C49
.1UF
C42
560UF
C50
.47UF
CR27
SNUBBER
C53
100PF
C55
NOT INSTALLED
CR17
C32
560UF
L1
4.7UH
C31
560UF
C35
560UF
+5V
CR13
W1
0 OHM
W2
0 OHM
+40VA
+5D
+5V
C33
10UF
C37
560UF
NC
J4
CONNECTS
TO J4
A3
MAIN
BOARD
+100V
+5V
+15V
+40V
<4>
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10
J4
ZAXIS
FOCUS
J4--- 1
A4
A4
D5
<8>
<8>
<8>
+5V
Q11
ERROR
R13
100
R14
10.0
5.1V
VR3
H
BOUNDARY
ISOLATION
Q9
R86
.51
R90
2.4K
CR20
Q9
R87
22.1
R82
4.99K
R81
178
R101
49.9
NC
NC
R88
2.00K
+5VC
R79
49.9K
C58
200PF
C51
.01UF
C
L
1
1
CX
6
RX
7
B
10
A
9
Q
12
Q
5
U4B
74HC221A
C59
.1UF
R96
49.9K
R75
4.99K
+5VC
R78
3.74K
R95
4.53K
3
2
1
8
4
U3A
LM393
R74
4.99K
C43
.47UF
C52
.01UF
+5VC
+5VC
FEEDBACK
TRANSFORMER
DRIVER
NC
NC
NC
C45
.47UF
C48
200PF
R80
2.00K
+5VC
+5VC
+5VC
C
L
3
VCC
16
GND
8
CX
14
RX
15
B
2
A
1
Q
4
Q
13
U4A
74HC221A
R77
100
G D S
AMPLIFIER
C41
.47UF
C39
.1UF
+5VC
C61
470PF
CR15
1
2
4
3
T2
Q8
CR29
R62
100
C40
4700PF
R98
10.00K
+40V
10V
CR26
VR1
VR4
R68
178
R71
221K
+5V
R69
10.00K
R70
10.00K
R99
100K
+5V
+5V ADJUST
R85
100K
POWER
FRONT
PANEL
(OPEN = ON)
--- 15V
S1
1
2
1
2
J2
TP1
LINE SIDE COMMON
SECONDARY GROUND
(CHASSIS GROUND)
R72
10.0
R73
10.0
TP2
+5VC
+5VC
CR16
Q7
C46
.01UF
PEAK
DETECTOR
R83
10.00K
+5VC
R76
3.74K
R84
18.7K
C60
.1UF
1705A SPECTRUM MONITOR
LOW VOLTS POWER SUPPLY <7>
AND SERIAL NUMBER RANGES.
SEE PARTS LIST FOR EARLIER VALUES
NOTE:
PART OF A1 POWER SUPPLY