Sanyo MR-1020 - Troubleshooting Chart: Electric Circuit Issues; Troubleshooting: No Playback; Troubleshooting: Recording Issues; Troubleshooting: Hum Issues

TROUBLE
SHOOTING
CHART
(Electric
circuit)
———_———————
lie
ete
Causes
Corrections
No
play
back
1.
Faulty
amplifier
power
source
circuitry.
1.
Examine,
using
wiring
diagram.
(using
recorded
tape).
:
2.
Disconnected
or
short
in
RP
head.
:
2.
Replace.
Weak
playback
:
3,
Misconnected
RP
change
slide
switch,
or
the
set
is
in
re-
:
3.
Replace
RP
change
slide
switch
or
adjust
Output
power
cording
condition.
spring
and
mechanism.
(using
recorded
tape).
4.
Faulty
speaker,
speaker
cord
or
connecting
jack.
!
4.
Examine.
Replace
if
necessary.
5.
Tape
oxide
deposit
and
dust
on
the
RP
head.
5.
Clean
head
(at
the
same
time
clean
the
i
pinch
roller).
'
6.
Faulty
connection
of
tape
and
head
surface,
and
faulty
|
6.
Examine
tape
position
and
pressures.
pad
pressure.
7.
Magnetized
head.
17.
Demagnetize.
8.
Faulty
head
position
or
worn
head.
18.
Confirm,
readjust
or
replace.
Impossible
to
record
or
insuf-°
{,
Oscillation
circuit
not
functioning.
4,
Examine,
using
wiring
diagram;
replace
ficient
recording
volume
(play-
faulty
part.
back
normal).
2.
Faulty
connection
or
movement
of
recording/playback
;
2.
Examine
the
switch
and
RP
change
lever,
slide
switch,
.
adjust
the
mechanism
and
replace
faulty
parts.
3. Faulty input jack and shield wire, or faulty connection. 3. Examine, repair.
| 4. Faulty Mic. or input recording cord, or faulty con- 4, Examine. repair.
nection.
5. Short in erase head. 5. Replace.
Faulty c or non- -existent erasing. . Disconnection or faulty connection | “of erase head. ' 1, Connect.
5 Tape oxide dust on erase head. 2. Clean head.
3.
Misconnected
circuit
before
erase
head,
especially
con-
3.
Examine,
repair
and
solder;
follow
the
necting
part.
:
wiring
diagram.
a
Oscillation
circuit
does
not
function,
:
4,
Examine,
using
diagram.
‘Loud
‘hum
(VR
a
at
“qaininninnys
‘L.
Faulty
transistors
after
VR.
he
Replace.
_
2.
Lowered
filter
capacity
or
misconnection.
|
2.
Replace.
|
3.
Faulty
lead
cord
connection.
3.
Replace
lead
cord.
Loud
hum
(VR
at
maximum).
.
Ground
lead
is
qouching
head
part:
The
hain
can
come
|
on
Examine
each
ground
dermninal”
and
lead
7
from
any
point
where
the
earth
lead
is
touching.
cord
connection
point,
other
points
in
con-
|
tact
with
ground
lead.
|
2.
Faulty
or
misconnected
lead
cord.
|
2.
Examine
and
change
lead
cord.
|
3.
Faulty
driver
transistors.
|
3.
Replace.
:
4,
Filter
capacity
leak
or
disconnection.
4.
Replace.
|
Hur
when
éannented
i
with
stereo.
a,
Earth
cord
touching
points
in
adaiion
to
amp.
and
|
ce
Examine
ground
cord
stereo
ground
terminals.
touching points.
Too
noise,
1.
Faulty
volume
contact,
lee
Replaces:
2.
Faulty
transistors
(especially
first
stage).
2:
Locate
faulty
transistors
and_
replace.
|
3.
Weak
circuit
element
faulty
soldered
contact
to
adjacent
|
3.
Examine,
using
wiring
diagram,
element.
4.
Head
magnetized.
a
a,
Demagnetize.
5.
Distortion
of
bias
oscillation
wave.
[>
Examine
and
adjust
circuit
element.
Panis
esting,
1.
Faulty
circuit
element
and
transistors.
ae
Examine,
using
wiring
dinerain:
'
2.
Poor
high
frequency
bias.
_
2.
Readjust
according
to
adjustment
chart.
3.
Faulty
tape-head
setting.
'
3.
Check
tape
setting
and
clean
it.
'
4.
Worn
out
head.
|
4.
Replace.
'
5.
Faulty
microphone
or
speaker.
|
5.
Replace.
-_
:
nee
.
6
Faulty
pad
Pressure.
.
6
Check
and
adjust.
Fault
treble
tone.
ao
Faulty
vertical
alignment
of
head.
ia.
Correct
by
adjdsting
macrhOd:
i
2.
Faulty
pad
pressure.
2.
_
Check
and
adjust.
Cross:
talk.
.
Faulty
top
and
bottom
position
of
head.
1,
ened
by
adjusting
eto
i
-
bs
pe
nee
iB
Faulty
tape
-
guide
position.
2.
Readjust
position
of
tape
guide.
Output
power
varies
“(channel-
'¥.
Amplification
too
small,
1
Adustwecordiwievel
==
°°
channel).
1
2.
Amplification
too
large.
es
Adjust
gain
balance.
No
jpovement
of
vu
meter.
|
3
Broken
VU
meter.
op
Replace.
we
Ted
:
.
2.
Faulty
VU
meter
adjustment.
|
2.
Readjust.
3.
mats
wiring
for
meter
or
recording
playback
change
3.
Examine
and
replace.
switch.