Marantz PM140 - Introduction and Servicing Information; Printed Wiring Boards (P.W. Boards); Test Equipment for Servicing

INTRODUCTION
This service manual was prepared for use by Authorized
Warranty Staions and contains service information for the
Marantz Model PM140 Stereo Console Amplifier.
Servicing information and voltage data included in this
manual are intended for use by knowledgeable and ex-
perienced personnel only. All instructions should be read
carefully. No attempt should be made to proceed without
a good understanding of circuitry operation.
The parts fist furnishes complete ordering information.
Most replacement parts should be ordered from the
Marantz Company. However, a simple description is in-
cluded for parts which can be obtained locally.
1. P.W. BOARDS
As can be seen from the circuit diagram the chassis of
Mode! PM140 consists of the following units. Each unit
mounted on a printed circuit board is described within
the square enclosed by a bold dotted line on the circuit
diagram.
1. MainAmp. ........ mounted on P.W. Board P700
2. Volume/Tone/Lamp. .. mounted on P.W. Board PEOO
3. Power switch ....... mounted on P.W. Board PGOO
4. Head Phone Jack .... mounted on P.W. Board PW00
2. TEST EQUIPMENT REQUIRED FOR SERVICING
i =
Item
Use
Distortion Analyzer
Audio Oscillator
ACVTVM
Oscilloscope
Circuit Tester
Distortion measurements
Sinewave and squarewave signal source
Voltage measurements (AC)
Waveform analysis and trouble shooting and ASO alignment
Trouble shooting
I DC VTVM
Voltage measurements (DC)
AC Wattmeter
Monitors primary power to amplifier
Line Voltmeter
Variable Autotransformer (0 ~ 140V AC, 10A)
Adjust level of primery power to amplifier
Shorting Plug
1. The secondary winding of the power transformer has
special AC power outputs for the power supply units
of the tuner and tape deck.
2. The ON/OFF switching of the speakers uses the head-
phones jack rather than a manual switch.
3. Since this unit uses an idling non-adjustment circuit,
when replacing the parts, be sure to use the correct
idling resistors and the proper rank power transistor
and variable resistors.
Monitors potential of primary power to amplifier
Shorts amplifier input to eliminate noise pickup |