User's Manual

3 - Troubleshooting
28
Connect a DC cou
p
led
sco
p
e set to 1mS/20V/
div across the out
p
ut
and turn on the su
pp
l
y
while observin
g
the
sco
p
e for a momentar
y
p
ulse
g
reater than the
su
pp
l
y
ratin
g
Does the su
pp
l
y
overshoot?
Yes
Disable the OV circuit
as described in
p
ara
g
ra
g
h "Disablin
g
Protection Features"
No
Out
p
ut
@
zero
volts?
4V
@
A1R350-2?
A
2 or W7 Defective
No
Yes
No
+.3V
@
U306B-7?
Yes
Check C336, R356,
R351, R349
(
1-2
)
and
U306B
No
+4V
@
U306-8?
Yes
Check C335, R354,
R350
(
1-2
)
and U306B
Go to sheet 5
No
Yes
Go to “Troubleshootin
g
Hi
g
h Out
p
ut Volta
g
e”
(
sheet 7
)
Figure 3-1 Sheet 4. OV at Turn-On