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5-37
5-38
t o Fig
a l i s t
semic
l i s t s
condu
listed
part n
Step
1
2
Refer
Desig
:PAIR AND REPLACEMENT
Table
5-4.
Action
Adjust
the
power
supply
output
t o
300
Vdc
and
disconnect
the
load
from
the
output
terminals
Remove
CR7
lead
?fore servicing a printed wiring board, refer
e 5-6.
Section
VI
of this manual contains
E
replaceable parts.
Before replacing a
lductor device, refer to Table 5-5 which
3
special characteristics of selected semi-
ors.
If t h e device t o b e replaced i s not
nTable 5-5, the standard manufacturers
nber listed i n Section
VI
is applicable.
After replacing a semiconductor device, refer to
Table 5-6 for checks and adjustments that may be
necessary.
High
Output
Voltage
Troubleshooting
Response
a.
Output
decreases
Short
Q4
emitter
t o
collector
5-39 ADJUSTMENT AND CALIBRATION
Probable
Cause
a.
R35,
R24,
or
R23
defective
b.
Output
remains
high
a.
Output
remains high
b.
Output decreases
a.
Output
remains
high
b.
Output
decreases
a .
Output
remains
high
b.
Output
decreases
4
5
5-40 Adjustment and calibration may be required
after performance testing, troubleshooting, or
repair and replacement.
Perform only those ad-
justments that affect the operation of the faulty
circuit and no others.
b.
Reconnect
CR7
and
proceed
t o
Step 3
a .
CR10,
R26,
R27,
or
CR8
shorted
b.
Remove
short
from
Q4
and
proceed
t o
Step
4
a.
Q4
open
b.
Remove
short
from
Q2
and
proceed
to
Step
5
a.
Q2
shorted
b.
Q1
shorted
or
associated
components
defective
Switch
S2
open
Resistors
R1-R15,
or
R21
.
open.
Short
Q2
emitter
t o
collector
Short
Q1
emitter
t o
collector
Table 5-5.
Selected Semiconductor Characteristics
~ c e
I
2,CR4-CR6
19,CR20
7 , CR21-
R2
9
R34
@
Stock No.
tor
Suggested
Replacement
Characteristics
Si. Stabistor 200 mA 10 prv
Diode, Si.
Rect. Si. 500 mA 200 prv
Diode, zener 6.2 V &5%
I
1901-0461
1901-0033
1901-0026
1902-0049
l N 4828 G. E.
l N 279 Transitron
1N 3253 R.
C.A.
1 N 7 5 3 Motorola
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