Marantz PM243 - 3, Test Equipment Required for Servicing; 4 Upc1270 H (0701, 0792) POWER AMPLIFIER DRIVE; Acutaieg

3. TEST EQUIPMENT REQUIRED FOR SERVICING
This
table
lists
the
test
equipment
required
for
servicing
the
Model
PM243/
143
Stereo
Pre
Main
Amplifier.
a)
Voltage
measurements
(AC)
_
|
|
ACVTVM
—
Oscilloscone
—
Waveform
analysis
and
trouble
shooting
and
ASO
alignment
=
Trouble
shooting
| |
.
| |
DC
VTVM
a
|
4
Voltage
measurements
(DC)
Circuit Tester
Variable
Autotransformer
(0
~
140V
AC,
10A)
Adjust
level
of
primery
power
to
amplifier
|
Shorting
Plug
Shorts
amplifier
input
to
eliminate
noise
pickup
4.
yPC1270H
(0701,
0792)
POWER
AMPLIFIER
DRIVE
| | | te
uPC1270H is a semiconductor integrated circuit developed Pin Connections
for driving stereo Hi-Fi power amplifier.
The
internal
circuits
consist
of
a
voltage
amplifying
circuit,
T
pinno.
|
Connection
pre-drive
circuit,
drive
circuit,
and
protection
circuit.
It
has
wai
+Vcep
(Pre
Driver
Regulator)
.
an external shape of a 12-pin smiall-size single in-line
package.
eel
+Vccp
(Pre
Driver
Regulator)
| 3s MUTING
| INPUT ~
Fg
—Veccp
(Pre
Driver
Regulator)
[|
10
—Vccd
(Drive
Regulator)
LOWER OUTPUT
UPPER OUTPUT
:
+
cop
.
+V
cep
MUTING
(FORWARD)
(ORIVER}
12
NO INVERTING
{POWER DRIVER)
INPUT Differentiat Protection
INVERTING Amplifier Circuit
INPUT
OUTPUT
2
(POWER DRIVER)
—Vecp FREQUENCY COMPESATION (BIAS }. ~V cep
Wecnecros (DRIVER }
Mae
_—