Technics SUX 997 Service Manual

Page 2

SU-X977

I CONTENTS

BEFORE REPAIR
PROTECTION CIRCUITRY .
ACCESSORY
LOCATION OF CONTROLS . . . . .
CONNECTIONS ............... .. 4,
DISASSEMBLY INSTRUCTIONS .
BLOCK DIAGRAM
SCHEMATIC DIAGRAM .........................

DESCRIPTION OF FL PANEL
TERMINAL GUIDE OF ICS,
TRANSISTORS AND DIODES .....
PRINTED CIRCUIT BOARDS
WIRING CONNECTION DIAGRAM .
FUNCTIONS OF IC TERMINALS ...
RESISTORS AND CAPACITORS .
REPLACEMENT PARTS LIST ...

EXPLODED VIEW

I BEFORE REPAIR

(1)Turn off the power supply. Using a 100, SW resistor
capacitors(C701,C702,6800pF) in order to discharge the voltage.

(2)Before turning the power supply on , after completion of repair , slowly apply the primary voltage by using
a power supply voltage controller to make sure that the consumed current at 50Hz/60Hz in N0 SIGNAL mode
should be shown below with respect to supply voltage 110V/127V/220V/240V.

connect both ends of power supply

Power supply voltage AC110V AC127V ACZZOV A0240V
Consumed current 50Hz 241 ~ 733mA 223 ~ 669mA 122 ~ 365mA 112 ~ 336mA
Consumed current 60Hz 233 ~ 698mA 217 ~ 650mA 119 ~ 356mA 110 ~ 330mA

I PROTECTION CIRCUITRY

The protection circuitry may have operated if either of the following conditions is noticed:

* No sound is heard when the power is switched ON.

* Sound stops during a performance.

The function of this circuitry is to prevent circuitry damage it, 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 this unit are used.

If this occurs, follow the procedure outlined below:

1.Switch OFF the power.
2.Determine the cause of the problem and correct it.
3.Switch ON the power once again.

Note:

When the protection circuitry functions, the unit will not operate unless the power is first switched OFF and then
ON again.

I ACCESSORY

0AC power supply cord ............................ 1
Configuration of Ac power supply cord differs according to
area.

SJA173 .......... For (GN) area only.
SJA188 . . . . . .For(EB) area only.
SFDACOSE03 . . . .Forothers.