Technics SX-PR270 M - Servicing Precautions and Safety; Waveform Measurement Guidelines; Component Identification Marks

PRECAUTIONS BEFORE SERVICING
@ Precautions for measuring of the output waveforms.
1.
The
waveform
was
measured
with
a
“National
Digital
Storage
Oscilloscope
VP-5730A’.
Therefore
the
waveforms
of
musical
tone
signals
shown
may
differ
somewhat
due
to
the
difference
in
the
timing
of
triggering.
2.
Since
the
1/10
test
probe
is
used,
the
indicated
voltage
value
on
the
bottom
part
of
each
waveform
photo
is
1/10
of the
actual
value
(e.g.
0.2V/cm should
be
2.0V/cm).
3.
To
measure
the
waveforms,
first
set
this unit
to
the
self-diagnostic
mode
(refer
to
page
I-15,
No.
4).
The
WAVE
ROM
output
will
then
be
output
as
a
sine
wave
to
facilitate
the
servicing
check.
i Important safety notice:
Components identified by a /\ mark have special characteristics important for safety.
When replacing any of these components, use only manufacturer's specified parts.
i Symbolic Marks
The symbolic marks for resistors and capacitors which used in this circuits are classified as following TABLE-1
and TABLE-2.
1, RESISTORS
¢ Resistors without symbolic mark are FIXED CARBON FILM RESISTORS (ERD-type).
*All resistors are 1/4WATT, +5% TOLERANCE unless otherwise designated in the schematic diagrams.
| ©” Fixed Metal Film Resistors
““FLAME-PROOF” (ERX—type)
Fuse Type Fixed Metal Oxide Film
““FLAME-PROOF” (ERF—type)
3) Resistors “FLAME-PROOF”
® Fixed Metal Oxide Film Resistors Fuse Type Fixed Carbon Film Resistors |
‘“‘FLAME-PROOF” (ERG—type) ‘“‘“FLAME-PROOF” (ERD2FC—type)
(ERQ—type)
Fixed Metal Film Resistors (Precision and High Stability) (ERO—type)
(TABLE-1)
SYMBOL SPECIFICATION
® Fixed Carbon Film Resistors
““FLAME-PROOF” (ERD—F—type)
@
Fixed Wire Wound Resistors
2. CAPACITORS
* Capacitors without symbolic mark are POLYESTER CAPACITORS. (ECQM-type, ECQG-type, +10% Tolerance)
* Polarized capacitors without symbolic mark are Aluminum Electrolytic Capacitors.
(ECEA—type, +20% Tolernace)
(TABLE-2)
SYMBOL SPECIFICATION TYPE
ECEA_.KN__type
AN) Non-Polarized Electrolytic Capacitors
Non-Polarized Electrolytic (for Network System)
ECEA__Y__type
Aluminum Electrolytic Capacitors (Low leakage current type)
|
ECEA__M__type
Aluminum Electrolytic Capacitors (Low impedance type)
ECEA__Z__type
Tantalum Solid Electrolytic Capacitors
ECS__type
Metalized Plastic Film Capacitors (TF Series)
ECQV__type
Y
WS)
oa)
®
CTE)
Polyester Film Capacitors
ECQB__type
Temperature Compensating Ceramic Capacitors
ECC__type
High-Dielectric Constant Ceramic Capacitors
ECK__type
ECR__type
Ceramic Capacitors (Cylinder type)
+4
ECBA__type
Metalized Polyester Film Capacitors for Across the Line
ECQ__EW__type
4.
Aluminum Electrolytic Capacitors for Smoothing Circuit
Multilayer Ceramic Chip Capacitors
ECES__type
ECUV__type