Panasonic su ch 80 service manual

Page 2

SU-CH80

I CONTENTS

0 BEFORE REPAIR ANDADJUSTMENT..
0 PROTECTION CIRCUITRY.
- ACCESSORIES...
- CAUTION FOR AC MAINS LEAD
- CONNECTIONS
- LOCATION OF CONTROLS

- SELF-DIAGNOSISMODE... ..... 38
- GENERALINSPECTION .....
0 WIRE CONNECTION DIAGRAM
0 BLOCK DIAGRAM ...................
- MECHANISM PARTS LOCATION.
- MECHANISM PARTS LIST ......
0 DISASSEMBLYINSTRUCTIONS 0 CABINETPARTS LOCATION.
0 TERMINAL GUIDE OF le, TRANSISTORS & DIODE 0 REPLACEMENT PARTS LIST
- SCHEMATICDIAGRAM ....................................................... 15 ~ 27 - RESISTORS&CAPACITORS....

0 PRINTEDCIRCUIT BOARD..., .26 ~ 34 - PACKING MATERIALS&ACCESSORIES.
0 TERMINAL FUNCTION OF |C'S.. ..... 35 . PACKAGINIG ..........................................

I MEASUREMENTSANDADJUSTMENTS .......................... 36 & 37

IBEFORE REPAIR AND ADJUSTMENT

Disconnect AC power, discharge both Power Supply Capacitors 0541 and 0542 through a 109, SW resistor
to ground.

DO NOT SHORT-CIRCUIT DIRECTLY (with a screwdriver blade, for instance), as this may destroy solid
state devices.

After repairs are completed, restore power gradually using a variac, to avoid overcurrent.

Current consumption at 230V, 50Hz (E, EG areas) in NO SIGNAL mode should be less than 310 mA or
Current consumption at 240V, SCI-l2 (EB, GN areas) in NO SIGNAL mode should be less than 300 mA.

I PROTECTION CIRCUITRY

The protection circuitry may have operated if either of the following conditions are noticed :
- No sound is heard when the power is turned on.
- Sound stops during a performance.

The function of this circuitry is to prevent circuitry damage if, for example, the positive and negative speaker
connection wires are "shorted", or if speaker systems with an impedance less than the indicated rated impedance of
the amplifier are used.

If this occurs, follow the procedure outlines below :

1. Turn off the power.

2. Determine the cause of the problem and correct it.

3. Turn on the power once again after one minute.

Note :
When the protection circuitry functions, the unit will not operate unless the power is first turned off and then on again.