2)
IC53
oscillates
abnormally.___.The capacity
of
Cl19
{0.33µ)
may
be
deficient or
IC53
may
be
defective.
3)
IC54
oscillates
abnormally.~The
capacity
of
Cll8 {0.33p)
may
be
deficient or
IC54
may
be
defective.
4.
Increase/decrease of current
1)
When
the
+SVDC
output
is
greatly
changed,-~~
Check
if
Rl57
{39
ohms)
the thermal protector of
IC53
is
working.
is
broken
down.
2)
When
the
+12VDC
output
is
greatly changed,-----.
Check
if
Rl55
{33
ohms)
the thermal protector of
IC54
is
working.
is
broken
down.
3)
Both
the
+SVDC
and
+12VDC
outputs are -----~Check the
AC
power
supply
greatly
changed.
voltage.
It
should not
exceed
125V
or
250V.
NOTE:
Even
though
a great voltage
;s
measured
at
the
+SVDC
and
+12VDC
outputs
when
the
power
supply
board
is
in no-load
state
with
CN8
removed,
the unit
is
considered to
be
in
normal
state
in case the
rated voltage
is
obtained with the rated load.
1.2
AC
Attach the
AC
cord to the unit.
Connect
the unit to the
AC
power
supply through
an
ampare
meter {lA).
Turn
on
the
power
switch of the Theta-5000£.
See
if
the input/output voltaoe of
IC53
{7805)
and
IC54
(7812)
are
as
shown
below.
Also
see
if
there is
no
abnormal
oscillation
at
the
+SVDC
and
+12VDC
outputs.
Ci]
AC
power~
supply f
AC
Voltage
AC
Current
IC53,
IC54
IC53
Output
IC54
Output
Input Voltage
115V
approx.
O.SA
approx.
22V
4.8V
-
5.2V
11.SV
-
12.SV
{ripple
under
2Vp-p)
220V
approx.
0.25A
approx.
21
V
4.8V
-
5.2V
11.SV
-
12.SV
(ripple
under
2Vp-p)
[PROBLEMS]
Refer to the
[PROBLEMS]
in
the
11
1.l
DC"
section.
- 2 -
