Service manual
• Trouble Shooting Chart (DBOXD0004PAZZ)
Problem 1: No voltage appears
at
any
output
terminal.
Is there
AC
220V
present across
C101?
Problem 2:
-5V
is
not
developed.
Check
for
AC
cord,
AC
socket,
AC
switch
and C101.
Check
for
F 1
01
and T101
Check
for
T1 01.
Is
there
AC
9V
present across
the orange
lead?
No
Check
for
F201,
0201
and C201.
Is there DC
10V
present across C201?
Problem 3: +12V
is
not
developed.
Is
there
AC
20V
present across the
yellow
lead?
No
Is
there DC
23V
present across C301 ?
Problem 4: +5V
is
not
developed.
No
F-1
Check
for
T101.
Is there
DC-5V
present across C202?
Check
for
0301
and
0302
(short-circuit
after
rectification).
Is there DC
12V
present
across C404?
1
No
No
Check
for
IC1,
R201,
VR201
and C202.
Check
for
L201 and
Ok
F202.
No
Check
for
IC2
and its
peripheral parts.
Leave
R403
be open;
does there appear
0.3Vp;,p pulse at
pin
181
of
IC2?
Check
for
L402
and
F401.
N
n
Check
for
IC3 and
its
peripheral parts.
Is there
AC
20V
No
Check
for
0301
and
0302
.----
present across the
I--
r
(short-circuit
after
yellow
lead?
rectification).
H Check
for
output
H
Is
there DC
23V
r-
Ok
switching
circuit.
Ok
present across C301?
U
No
Leave
R503
be open:
-
does there appear
Is there DC
5V
across
~
@
Vp-p
pulse
at
pin
Ok
C507?
of
IC3?
Check
for
L503
Ok
and
F501.
-13-
MZ-80K
l
-